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In footnotes or endnotes please cite AIP interviews like this:
Interview of Walter Brattain by Alan Holden and W. James King on 1964 June,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Early experiences in science at Whitman College, Washington, from 1920; friendships with fellow students and teachers. Graduate study at University of Oregon and Harvard University; difficulties funding education; study with Edward A. Milne at Oregon and John Van Vleck at Harvard. Work at National Bureau of Standards on piezoelectricity and oscillators; work at Bell Labs on thermionic emission and experimental basis of statistical mechanics; influence of Arnold Sommerfeld on his work on the copper oxide rectifier. World War II work with National Defense Research Council on the magnetic head of submarine detectors. Return to Bell Labs following World War II; research in solid state with group headed by William Shockley and Stanley O. Morgan; preliminary researches in semiconductor effects.
Well, Walter, I tell you, we might start this way: I think of you as a Chinaman. Am I right?
Yes, I was born in China, I usually say, because my parents were there.
But you weren’t there very long, were you?
No, I can back here when I was a year and a half old.
Did you get an early interest in science the way so many do? I did. I began messing around with chemistry at the age of eleven.
I was certainly interested in things scientific in high school. My first real interest, the first pleasure I got out of schooling, was in arithmetic. We would hardly call it mathematics at that stage. And I remember having tried to build an electrostatic machine while I was in high school.
But I think Whitman College was really where your interest was solidified.
And mostly at the hands of Professor Brown. Is that right?
Yes. I should say that my father had graduated from Whitman College, and my mother had gone to Whitman College until she transferred to Mills. So that in a sense I was going back to my parents’ school. And both Professor Brown and the man who supplemented him in mathematics, Professor Bratton, had taught my mother and father. This combination was very powerful in interesting people in science. Professor Brown and also Professor Bratton had had a long record of having from time to time, out of a small liberal arts college (at that time there were only 500), turned out people who went on. One of the earlier ones that everybody is acquainted with is Mrs. Quimby, who was a student of Brown and Bratton.
I remember that your own classmates included such people as Vladimir Rojansky. Was Walker Bleakney there, too?
Yes, it happened that Walker Bleakney and I showed up at Whitman College as freshmen in 1920 together, and during the course of our stay at Whitman two other men came in: Workman, I think, as a sophomore, in the second year, and Rojansky as a refugee from Kolchak’s Army in Siberia — this would be the fall of ‘22 — and solely on the basis of what he was able to tell them about his education in Russia (he had no records), they allowed him to matriculate as a junior. This turned out to be the biggest single class that Brown ever had.
Can you put your finger on the ingredients of Brown’s influence and success here? This is one of these mystical matters almost associated with teaching that fascinates me.
Well, this is not easy to do. He had, of course, taught by this time for some 35 years — maybe not quite 35, but at least 30. At the beginning, he taught all science at Whitman College, and then as the college grew in faculty, he restricted himself to physics and to a popular junior elective course in geology and astronomy. He took an interest in every student that came to the college, regardless of whether they majored in his department or not. He was willing to talk to almost anybody who would listen, to describe the physical environment as he had learned to know it, starting from the immediate surroundings, peering out into space as far as you could peer through telescopes. He distinctly had, in my estimation, a philosophy of life that came out of his knowledge of the physical universe. He wished to express it to almost anybody. In words that I remember he would suggest that when one looked at the expanse of the universe and considered this little insignificant planet around this less-than-average sun that the day-to-day affairs upon the surface of this planet were hardly things to get angry about; they were hardly that significant. I would like to quote one other thing here from Brown just to put it in the record. This is a direct quotation from some little pamphlet that he wrote once to explain things to laymen: “The Earth wobbles like a big spinning top about to fall. In twelve thousand years the North Pole of the Earth will point not towards the North Star as at present, but toward the Star of Vega, 47 degrees from the North Star. The movements of the Earth are complicated. On August 24th, at 9 o’clock p.m., 1927, all Walla Wallans were moving westward at 700 miles per hour due to the Earth’s rotation and it’ll go eastward 70 000 miles an hour due to the Earth s revolution about the sun, and 43,000 miles an hour directly upward due to the Sun’s motion among the stars. The activities with which men busy themselves about town are infinitely small as compared with the movements of the world machine on which they live.”
It’s not easy to combine that sense of one’s own smallness with the sense of the importance of what one is doing, and it seems to me that Brown was able to do both. He seems to have had an interest in physics and an interest in people which were very well balanced.
He loved physics and he loved people.
How about his lectures? Did he have very elaborate demonstrations in his lectures?
He did not have a great deal of money available. At that time what equipment he had and what demonstrations he had were built by himself. He had several very interesting ones. He designed these things for participation, even in his lecture course. For example, he had a bicycle wheel from which he removed the tire and replaced it with a lead tire, so that it had considerable weight, and it was on a nice ball bearing so that if it was set spinning it would spin for some time. And it had a handle on one end, and he’d let you take a hold of it, so that you could feel what gyroscopic action amounted to. In another case, he had a rotating table which you could stand on, and he’d give you a couple of weights — he’d have you hold your hands out straight with the weights in them — and he’d set you rotating on the table slowly and ask you to pull your hands in. In every respect he tried to do this, and he distinctly tried in all our laboratory work to get us to approach the laboratory from the standpoint that here was your opportunity to find out for yourself. In fact, he used to say that once anything is written down it has become a fossil.
I get the impression from the way you’ve preserved your laboratory notebooks from that day that it was perhaps the laboratory and his sense of the importance of making direct contact with nature that was a very important part of his teaching.
Yes. And he had been, though he never accepted it really, elected to Sigma Xi on the basis of research that he had done himself. He picked out a problem — that was the question of pulling of loads by teams — he was in farm country, and there were no automobiles in most of this period — and he forever tried to impress upon us that a horse could not pull more than its weight and its lever arm on its legs. He’d actually measured these things, convinced himself of this. And he also, for his own enjoyment, repeated a very famous experiment, the Cavendish experiment of weighing the Earth. He made his own apparatus, made his big Cavendish balance, and would come in late at night when things were quiet in the building with nobody walking around. He had it in the basement, and when there was nothing on the streets, it was sensitive enough so that he could detect teams or loads going along the street. We couldn’t take the raw data on this, but he made us start with the raw data that he’d taken, and from this analyze the data and calculate the weight of the Earth.
So that the students very definitely had a sense of participation in what he was doing in terms of the experiments and in the classroom demonstrations.
There was one very interesting lecture that I’ll never forget. Let’s see if I can find it quickly. I might just read from this experiment here, as I had written it up then; I wasn’t a very good writer at that time: “If it takes 140 dynes per square centimeter at 20 degrees to pull the edge off of a sheet of water — presumably from surface tension which we had measured in the laboratory — 140 plus 84 equals 224 dynes to pull it off without temperature change. 224 ergs work to pull one layer of molecules off a cubic centimeter of water.” Well, not to quote this whole thing, but to go on, he takes the cube and he pulls off layer by layer, and he sort of puts them back together, mentally, without touching, and then he pulls the sheets the other way, so that now he’s got rows. And then he finally pulls it the third way, so that now he’s got atoms. And he turns around and compares this energy with the heat of the vaporization of water, which we’ve also measured in the laboratory. And I think in comparing these two, he comes out with Avogadro’s number.
Had you decided then, when you graduated from Whitman, to go on in graduate work in physics? I know you went to Oregon for a year after that.
Yes. Two years. Somewhere between January and March, the four of us began to discuss a little bit and think about what we might be doing after we graduated from college. This did not concern us particularly, at least it had not concerned me. I majored in physics and math because I liked it, because if I worked there I could get good grades; I couldn’t do this if I worked in the other subjects. The first thing that occurred to focus our attention on this was the Harvard engineering scholarship that I think is still offered annually to one person in the United States qualified by exam. It was a thousand-dollar scholarship then. I presume it’s been increased some since then. We decided that we wanted to take this exam. For some reason or other we went to Bratton, not to Brown, and had Bratton arrange to send in and get the exam, and to give it to us. When it finally arrived, Workman said, “Oh, you fellows are wasting your time!” But the three of us, Bleakney, Rojansky and I, went over to the library and sat down where Bratton put us, and we took this exam. It had a time limit on it.
After we had taken it, we went over to a room that Brown had arranged for us — it was kind of our own room over in the Physics Department — and proceeded to go through all these questions — we remembered them — to figure out the mistakes we’d made and what the correct answers were. Working together we could easily solve all of them. We had decided that that was that, that we hadn’t done too well. I then, somewhat later, asked Brown about going on. I told him that I didn’t want to go on unless I could be at least better than average. In fact, I think I asked him whether he thought I had what it took to be a good physicist. I didn’t want to be a mediocre one. And he assured me that he thought I was capable of being a good physicist. In overall grades I was probably the lowest of this group of four — I mean overall in school — although in physics I was right up with them, at least in the last year. So, as a result of his assurance, Rojansky and I investigated the various schools. Cal Tech was one. It offered the most money but it requested the most work besides your work towards your degree. Oregon offered $500 the first year, for nine months, and $600 for the second year, and required — well, the program was set up on the basis that you could get a Master’s degree in two years. So, I think Rojansky and I both applied to Oregon, Rojansky in mathematics and I in physics. Rojansky was a math-physics major, too. And I think sometime — I don’t remember the exact timing — during the course of these things, we were very much surprised when one day word came through that Bleakney had won the thousand-dollar scholarship and that Rojansky was second in the whole darn country, and they had the courtesy to say that I was within the first ten.
Bleakney had been bellyaching at this time. Workman was going to stay and help Brown teach. And it was getting close to graduation and Bleakney said, “Well, I guess I’ll have to go back to farming.” Well, then the word came through that he had won this scholarship, Rojansky and I had these assistantships. It is of interest to me that these assistantships involved our doing laboratory instruction in undergraduate physics at Oregon, and I’ve always been impressed with the fact that having done this, both at Oregon and at Minnesota, that this was part of my education. That which you teach you learn at a different order of magnitude. And I’ve always felt that I understood my undergraduate physics in a way, except in very special areas, that I never understood the physics I learned in graduate school because I’d never taught it. I’ve never had to think it through in this manner. Actually, what Rojansky and I found at Oregon was an older physicist Boyton as the head of the Physics Department who liked to gossip about the earlier days of the Physical Society and if we worked his lectures right, could practically spend all of his lecture time gossiping with very little solid work done. And there was another man, Caswell, who was beginning in electronics.
The real solid material we got at Oregon came from the math professor W. E. Milne, who was also a graduate of Whitman College and had gone to Harvard to take his Ph.D. degree. He is even known now, even among the mathematics group over here, for his early work on the use of numerical integration of non-linear differential equations and the methods that are immediately applicable to computers, and so on. He gave us two courses in these two years: one, the Theory of Functions of the Complex Variable, in which he had no English text which he liked. We bought a Pierpont, but he recommended Osgood, which is only written in German. We mainly had to get it from his lectures. And the second year, Differential Equations of Mathematical Physics, and I still have this notebook. At least for part of the time we typed these out pretty thoroughly.
These were strictly lectures?
Yes, lectures, mathematics. There were no experiments. Rojansky’s job was to help Milne with a big nine-place Monroe calculator, to calculate some of his equations. That was his job; he wasn’t teaching actually. I was teaching in the physics lab, and I did a small Master’s thesis. I had one of the first Western Electric Cathode Ray tubes, not oscillographs. You were lucky to have the tube in those days. You found out that this tube was very sensitive to electrostatic fields wherever they were. Electronics was not even an art in those days. You knew nothing about shielding, about grounding, or anything. You overcame the situation by removing all the 60 cycles from your room. In fact, in the basement where I worked I arranged, when I was working with it, that the only 60 cycles was clear down the end of the building, down the hall, where I had a motor-generator. And I wanted DC in my room, and I had a switch to control this motor generator, to turn it on and off in my room. And I took oscillograph traces and photographs of resistance, inductance and capacity discharge through spark gaps, which is a little bit different than just the discharge of a capacity through an inductance and resistance and I tried to analyze the results by taking current voltage characteristics to determine as much as I could of what was going on.
Of course, the spark gap, after it has been started, has a negative resistance, and very peculiar characteristics. I still have one copy of that thesis around somewhere. So that was about it. And along about the middle of the second year, of course, both Rojansky and I began to think about going on further. I might tell one other incident here. One of my first assignments to help out in the Physics Department was to see if I could get a Millikan Oil Drop apparatus to work, which was just being made available by Central Scientific — they had purchased one. I followed the instructions very carefully and worked for some weeks, and was completely frustrated because, while I could get oil drops visible in the telescopes, I could not get any charges. The instructions were written in such a way as to suggest that the way you got charges on the oil drops was to turn on an X-ray machine nearby; it was one of the suggestions. And I was doing this religiously, until I inadvertently came in one day and started to observe things carefully before I turned on the X-ray machine, and was very surprised to find that I had an oil drop with a charge on it. And then, of course, after thinking about this, I realized that by turning on the X—ray machine, you were ionizing the air and successfully removing the charge from all the oil drops, that the oil drops in coming through the hole in the top plate, which had the potential on it, could hardly get through that hole without collecting some kind of a charge.
Did you write to the Central Scientific Company?
No, I didn’t bother, but I, having herded cattle as a boy, had some very profound words to say about it when I found this out, after having wasted about two weeks fighting it. We wrote to Bleakney, who had, of course, by this time had spent a year at Harvard and decided that he did not want to become an engineer but wanted to be a physicist, and he had spent a summer at the Bell Telephone Laboratories — this must have been the summer of ‘25 — working under W. A. Marrison. He accepted an assistantship at the University of Minnesota, and so we wrote him a letter asking him for advice. Milne kind of wanted Rojansky to go to Harvard, but Rojansky was completely self-supporting. I had been since I gradated; my parents had supported me through college, but I was self-supporting. Bleakney wrote us a very famous letter, (a copy is now in the AIP files) a copy of which I still have and I have threatened to publish sometime in The New Yorker, comparing Harvard and other things. He started out writing on the front side of sheets of paper, and finally he got tired, after about 10 or 11 pages, and turned them around and started writing on the back.
Well, as a result of this, Rojansky applied to Harvard and to the Math Department at Minnesota. Rojansky was pretty much aware that the Harvard Math department offered at that time no scholarship that would enable him to attend Harvard. I applied to Minnesota. Bleakney, having been informed of these actions independently, went over to the Math Department, found out that there were going to be no openings in the Math Department for the next year, and got Rojansky’s application to the Math Department transferred over to the Physics Department. And on the basis of the reputation that Bleakney had made at Minnesota in less than one year, Minnesota offered Rojansky and myself — and Workman, who had not even applied — assistantships for the next year. Workman refused to come; he said, “I’ve been helping Brown teach, and I’m way behind you boys. I’m not going to come and let you sneer at me.” But Rojansky and I went to Minnesota, where again we encountered — well, I never took a course with him, but I did my experimental thesis under him — Tate, and of course loved him.
What was the subject of that, by the way?
“Efficiency of Excitation by Electron Impact and Anomalous Scattering in Mercury Vapor.” Tate, of course, had gone, I forget which school, to Berlin, Germany, as many people used to. In fact, my age comes almost at the dividing line when it ceased to be necessary for an American physicist to go to Germany in order to finish up his degree.
Had you ever even toyed with the idea of going to Germany?
The Brodes, the two Brode boys, who were in Whitman when I was there went to Germany. And this was just about the dividing line when it was no longer necessary. Anyway, Tate studied under Franck, of Franck and Hertz, and took a degree there. And, of course, he came back to the United States aware of the excitation potentials by electron impact in gases of low pressure of less than the ionization potential. And, of course, he was aware of the fact that Millikan’s result of 4.9, plus or minus a tenth of a volt, for ionization potential of mercury vapor was a result done at very high pressures, where the process depended upon the square of the pressures. And since in such a gas each atom of which was excited to 4.9 volts plus some kinetic energy (this was close enough to 10.4) so that there would be some ionization in the gas. He did a little experiment, I think possibly at the Bureau of Standards, where I think he first went to work when he came back, and measured the first ionization potential again and presented an abstract to the Physical Society explaining that this 4.9 volts was actually the excitation of the 2537 radiation. And, as Tate himself told me the story, Millikan rose up out of the meeting and said, “Young man, I measured the ionization potential of mercury vapor myself, and it’s 4.9, plus or minus a tenth of a volt,” and then he sat down. Tate never forgave him! The other teachers there that we were very fortunate in having were Van Vleck, who was then teaching quantum mechanics every year, and electrodynamics, I guess maybe not every year. At that time the situation was such that we chose the year (we were at Minnesota) we wished to take his course for credit; we had to if we wished to be a Ph.D. But we had to listen to his course every year we were there, because quantum mechanics changed while I was at Minnesota, in essence from the Bohr orbit theory with the correspondence principle to matrix and Schrodinger wave mechanics.
Let me go back just a little bit. Did you have any contact with quantum mechanics before you had the course with Van Vleck?
The Planck’s quanta, I think, was brought into our courses at Whitman somewhat in the radiation law. I think Brown somewhere in his course — he, of course, got the key to the Fourth Law, the total radiation of a black body — got in at least some discussion of the distribution of the radiation. At least at Oregon — I can’t quite sure say, but beyond the fact that there was a quantum — Planck’s ideas from heat — this is about it. Oh, we must have had some concept of excitation potentials, I don’t know. Of course, Tate’s school at that time was completely devoted to what could be found out by excitation or ionization of atoms. Everybody working under him had some problem in this area of excitation of gas by electron impact or ionization of gas or efficiency of ionization. In fact, he wanted to know not just at what potentials these occurred but how efficient were these processes and how did they depend on the energy of the electron, provided that the energy was above the energy necessary to excite these radiations.
Was there much overlap between the course of Van Vleck and the experimental work of Tate?
No, Van Vleck’s course was completely theoretical.
It was more or less left to the students then to integrate these various areas.
Oh, yes, yes. Besides the two courses in electrodynamics and quantum mechanics, Valasek had an optics course that I took — this was during my stay at Minnesota — and Valasek is a wonderful teacher, always has been and still is at Minnesota.
Did he have a text for his course?
No. There were no texts for any one of these courses. These courses were taught by lectures, and you had to take notes. You had some references, yes, but there was no book, and in general the lectures were beyond anything that was in any available text, at least that we knew about. I later became acquainted with Jeans’ Electricity and Magnetism, and re-did a lot of things when I had to learn it for my own purposes. It was a big job; you had to get the notes down; you didn’t have time to relax and listen to the philosophy behind these things. You were too busy being sure that you had the steps down. I’ve learned later that there was much more to them than we got out of the courses at that time. Somewhere in the area either one of these people had put a pretty powerful course in thermodynamics. I had been excused from Tate’s theoretical physics course because it was thought that the differential equations in mathematical physics was a substitute for that. I probably should have been forced to take Tate’s course; it wouldn’t have hurt me at all.
That would have been mostly a course in classical theoretical physics.
In mechanics, yes. It was our good fortune — if I haven’t said it before — to take Van’s course in quantum mechanics for credit the year he taught matrix and Schrodinger mechanics. As it happened, Schrodinger came to Minnesota that winter, in the middle of this course, and Van of course prepared us for understanding what Schrodinger had to say. In those days there were great and profound questions about the meaning of the psi function, whether it was a statistical average over many atoms or what the psi-psi bar meant.
Didn’t Frenkel teach at Minnesota, perhaps after your time?
I think after my time. He was in this country, I know, and I think he was at Minnesota, but he was not there while I was there. Another man who was there though was Franck, and Tate had been doing some experimenting how to let students interact with such visitors. Of course, Franck was Tate’s thesis professor, and obviously Tate thought a lot of him. And he came to us, and this was an experimental physicist — often the traveling physicists were theoretical physicists. He came down and said to us, “Now, I want you boys to get acquainted with this man, and in order to do that, I want part of the program to be entirely up to you. I’m not even going to come around.” And at his suggestion we spent the afternoon with Franck and took Franck to dinner, entertained him at dinner out of our own pockets. Remember, we were getting $600 for nine months, $66.66 a month. And I still have a picture of Franck. I suppose you want that?
I’d like to copy it if I may.
You can certainly copy it. We snapped this in the middle of the deep Minnesota winter, in the deep snow, somewhat like it is out here now.
Did Franck remain at Minnesota very long? Or was it just a visit going through?
It was a visit of a few days.
Tate also seems to be a warm person with the graduate students.
They all felt very close to Tate.
Was he the kind of a man to drop into your lab, or would you have to go to see him?
He was then editor of the Physical Review, and he was a pretty busy man. He did not bother you on your research problem unless you asked him for help. In fact, there was no question about Tate, on any of these Ph.D.’s theses, being co-author, because while did help he wanted it to be your own work. I was fortunate in that I arrived at Minnesota when I did. People that arrived about two years earlier had to blow their own glass mercury diffusion pumps before they could start their experimental work. This was in the tradition of Swann, who was later at Bartol Research Foundation. And in those days one didn’t have pyrex either; there were soft glass diffusion pumps. But when I arrived there was a glass blower, and we did not have to make our diffusion pumps, and it was pyrex. We did have to learn to do minor repair jobs on our glass vacuum system.
That was also a tradition of Bridgman at Harvard. Every one of his graduate students had to become expert on a screw machine lathe. What took you to the Bureau of Standards?
Well, of course, in the spring of ‘28, those of us who had passed our prelims applied for jobs — I’d like to mention, of course, that Van Vleck was a very conscientious teacher here, in spite of the fact that he denies this, and he almost flunked me on my prelims, but I survived. The major portion of the group that was graduating were applying for a teaching job. I had made up my mind that I didn’t think I wanted to teach. I had become aware of the Bell Telephone Laboratories at Whitman College, because Brown had received the Bell Telephone’s Bell System Technical Journal, and among other things, there appeared from time to time articles by Darrow, trying to explain the newer things in physics in his gorgeous language. I had come in contact with M. B. Long of the Bell Telephone Laboratories. He used to make trips, not exactly recruiting trips but informational trips. I think he was actually at Whitman once, and I saw him again at Oregon. I became acquainted with Jack Cattell. He introduced me to Cattell once; he was there at Oregon for a little while and we played tennis together. And, of course, I knew of the Bureau of Standards, and somewhere in this process it looked like a dream at Oregon and at Whitman, but I had the dream at working in one of these two places. It never occurred to me then that I would ever reach that level. So, I only applied at the Bureau of Standards and at the Bell Telephone Laboratories, and I proceeded to go to work on my experimental work. I was free of my course work, had passed my prelims. All I needed now was data to write a thesis.
I, of course, spent both summers at Minnesota without pay, working at odd jobs and what have you, to get some money for the summer. If you needed a suit of clothes you found some little rich girl that couldn’t understand freshman physics and tutored her at a high price. But along about July all the other fellows had appointments and I had not heard from anybody, and I was just about at the place where I was going to go down and ask Professor Tate what I ought to do — I wanted to eat the next year — but I hadn’t done this; I was planning to the week, I think, that I received a wire from the Bureau of Standards suggesting that there was a position open in the radio section of the Bureau of Standards as assistant physicist, for I think somewhere around $50 or $55 a week. I was impressed of course by the telegram and by the idea that it needed immediate action, so I went over and talked to Tate about it. I asked Tate, “Can I qualify for this job? I know nothing about radio.” Tate said, “Well, you’ve read Pierce’s, Electric Oscillations and Electric Waves, haven’t you?” I said, “Yes. I haven’t taken a course in it but I’ve read it.” He said, “You know how to measure inductance and the capacity on a bridge, don’t you?” I said, “Yes.” He said, “I think you’ll qualify.” But he said, “I wouldn’t get excited. You may hear from Bell Telephone Laboratories yet.” “No,” I said, “I’ve faced no job long enough.” I answered this telegram and said I would accept. And a date was made for me to go down there. And I felt not too secure but I felt that maybe I had enough data so that I could get a thesis out of it if I worked on it. And so I borrowed some money, from Tate — I hadn’t had a check since June — and I was tired — it was one of those hot summers and I decided I needed a little relaxation. So, I went up to Duluth and got on a boat down through the Lakes and then went down to the Bureau and started to work.
Was Tate right? Did you ever hear from the Bell Telephone Labs?
Yes, I guess after I accepted this I had, oh, just a feeler, no offer of a job. Of course, it didn’t take me very long to find out that I, in this job, would very quickly become a radio engineer.
May I ask for whom you worked?
I worked under Dellinger, the head of the radio section. Jolliffe was the second in command, and I actually worked directly with or under a man by the name of Heaton. And the task that was given to me was to design a portable, temperature-controlled piezo-oscillator. The standards at the Bureau at that time were still tuning forks. There was a quartz crystal standard, a non-portable standard, at the Bell Labs made under the direction of W. A. Marrison. Actually, Heaton was a typical civil servant, full of all the information you could ask for. You didn’t need reference books. He was sitting at a desk across from me; the front of his desk was against the front of mine. I extracted from him the information and proceeded to use my hands to design and put this thing together. We published a paper on it. It weighed about 40 pounds. It was good to a few parts in a million. It was an engineering job; it was applying physical knowledge.
As I recall it, Valasek had been interested in piezo-electric materials.
Yes, but not as using them as an oscillator.
Were either Cady or Pierce visible at the Bureau of Standards in this work on oscillators?
I wondered whether they might have done consultation work.
There was a man, whose name I’ve forgotten, over in the corner of the laboratory, who was more interested in the why and wherefore of piezo-electric oscillations than in using them as standards. And a friend of mine, who was also a young man, Wright, was working with him. We used to fight back and forth about the thing. I was a little bit disgusted, although I probably knew this at the beginning, when after having successfully made this, Dellinger proceeds to take a trip around the world with it, comparing it with other standards.
Well, you made it portable!
I probably wouldn’t have worked quite as hard and quite as fast on it, if I had known that he was waiting for it just for that purpose.
And that it was going to disappear so rapidly.
Well, it came back there. We had it both before and after.
I think that was rather an important series of tests, wasn’t it?
Well, yes. This was the first time you had on one standard an inter-comparison of the frequency standards around the globe.
Wasn’t this the test where they compared with the National Physical Laboratories, the laboratory in Berlin, and one in Paris and one in Italy?
Oh, yes. Though that part Dellinger wrote up; we wrote up only the oscillator. It was written up as “Design of a Portable, Temperature-Controlled Piezo-Oscillator.” (Research Paper #153 Bureau of Standards Jour. March 1930 6 of these were made)
Well, was it your disgust with that that led you to the Bell System Laboratories?
No, M. B. Long visited the Bureau of Standards’ radio section one day, and it happened that I was the one man available, and I was delegated to show him around. And I showed him around, at least, our area, and I explained to him what we were doing. Our standards then were capacities and inductances which we kept and measured every once in a while. This was the routine work. He was sufficiently impressed at that time to tell me that anytime I wanted to work for Bell Laboratories to let him know. Well, I realized that he was interested in the type of work I was doing, that that was what was impressing him. So, I decided along about January that I wanted to be a physicist and not an engineer. And I had my mind all made up to the fact that when the April meeting of the Physical Society, which was to be held in Washington — it always was; in those days it was held in the Electrical Measurements Building, across the way from our shack — that Tate would be there and that I was going to proposition Tate as to how I was going to be able to get back into physics. I remember distinctly the morning I walked over to the Electrical Measurements Building and walked in, and the first man I met was Tate. I said hello to him and a couple of other physicists, whom I knew who were there. I was just about wondering when I’d get a word in edgewise to ask Tate for a few minutes to talk to him sometime during the meeting, when Tate introduced me to Becker, J. A. Becker of the Bell Telephone Laboratories. He said, “By the way, Becker is looking for a man. Are you interested?” and said, “I am interested.” Becker said, “How about having lunch together?” We had lunch together, and then we went for a walk in Rock Creek Park. Becker really only asked me one thing about my qualifications, and that was whether I would talk back. And it happened that Boyton from Oregon was also at the meeting and so was Tate, and I said, “Well, that’s one thing I’m quite sure of, that if you’ll just ask these two professors, you’ll find out that I am perfectly qualified in that respect.” So, I got my job at the Bell Telephone Laboratories.
That’s our boy Becker, all right!
Maybe this is a good place to stop the machine and do a little discussing. [Interval] Well, to go back a little bit, I labored long and hard of evenings and weekends on the data that I had taken at Minnesota to see if I could make any sense out of it. There were times when I thought it was not worthwhile going any further with it, but I was in no position to take any more data, and so I continued to labor. I finally came up with a write-up of material which I sent to Tate, and Tate accepted it. Arrangements were made for me to come back just after Christmas and take my final exam.
Who were the other members of your committee for the thesis?
I can name some of the people who were in at the final exam. Tate was there. F. H. MacDougall from chemistry, who is famous for a book on thermodynamics, was at the exam. I’m quite sure that Valasek was there. I’m not sure that Van Vleck was there; he may have already gone to Wisconsin. John Zeleny — I should look up to see whether it was John; one was also at Yale — was there, and he had worked out a way of teaching electricity and magnetism that was kind of his special idea. I was forewarned that he would ask me to define the EMF around a circuit. I very carefully boned up on the mathematical definition as the line integral around the circuit, so I knew it backwards and forwards. When he asked me this question, I stuck to that definition, and I would not be led out to less mathematical terms that he wanted to lead me out into. Sometimes, in those days, Zeleny was difficult. But of interest is that I arranged this trip to attend for the first time the meeting of the AAAS which was in New York the week after Christmas at that time. Tate was coming to it, and I was to meet him there and go back to Minnesota with him. Tate and I had New Year’s dinner in Chicago together, and then we went on to Minnesota, where I took my final exam. I’ve already discussed part of what went on during that final exam. I remember distinctly and with some chagrin that after the exam was over and after Tate had told me that I had passed, he bawled me out for not saying to some of MacDougall’s questions that I just didn’t know what he was talking about. I didn’t think I was trying to bluff, but Tate said that it appeared that I was trying to bluff. Actually, he (MacDougall) was trying to ask me some questions involving solids, what little solid-state theory we might have had in those days, like Debye’s specific heats and things of that kind, which for one reason or another I had not been exposed to.
This was about 1928, was it not?
Yes, this was the winter of ‘28-‘29. Then I should go back and mention that in the radio section at the time I was there, there was another group under Harry Diamond, who was doing very outstanding work in navigation aids to flying; in fact, he had the first radio range indicator for pilots. They had a practice range up between Philadelphia and Pittsburgh someplace, to see whether you could fly blind. And he continued on at the Bureau and became very famous. Outside of my particular section, being a physicist, I very quickly got into contact with a group of physicists who were in the Bureau and in the Carnegie Institute of Terrestrial Magnetism which was close by at that time. Among some of these people were Mohler, Meggers, Rudy Langer, who later went on to Minnesota for a while, Merle Tuve, Gregory Breit, Taylor, who is still at the Bureau of Standards, so far as I know, and a young South American physicist, Gaviola. This was a very interesting group of young men, some of them older, whose names I’ve forgotten now, whose primary interest was in physics. The particular jobs they were doing didn’t worry them; I mean, they got together for discussion and some of them presented papers on different things. We discussed new things that might have been written up in the Physical Review to see if we could understand them. This was still the day when any trained physicist-Ph.D., could hope to understand any paper written in the Physical Review.
Were there any questions as to the new quantum mechanics; that is, were they aware of the extent of the changes that this would bring?
Oh, yes. This was very much alive at that time. That, and the understanding of all spectroscopy, was a large portion of physics at this time. Well, finally, the bureaucratic red tape of becoming an employee of the Bell Laboratories was settled. I remember that after the walk in the park with Becker, I was invited to come down to the hotel during the meeting, the Mayflower Hotel, and to have dinner with Dr. Davisson and his wife, and Dr. Darrow. At my then salary the Mayflower Hotel was almost off-bounds; it was at that time the most fashionable hotel in Washington, D. C. This dinner was in the Mayflower’s main dining room, and I felt very much out of my depth. Of course, Davisson, since he was then Becker’s supervisor, wanted to have a look at me. This was the way it was done. I remember this now when we pull these tactics on young employees these days and wonder sometimes whether they’re embarrassed or not, although I think the present-day variety is a little bit more brash than I was.
Nowadays when we take them out to an expensive restaurant we pay their way. Davisson and Darrow, of course, always liked their food.
Well, they paid for my dinner!
Oh, they did.
What was your impression of Darrow and Davisson at that time? Can you recall?
Well, I had read Darrow’s little essays and of course was very interested to meet him. Davisson, of course, was already famous. I was very awed. I don’t know that I can remember very much about impressions; I was very much on my manners that evening. Anyway, it was arranged that I come to the Laboratories on August 1, 1929, and I suppose now you’d like a quick resume. At the time, Becker was very much interested in thermionic emission and the effect on thermionic emission of absorption of gases or other materials on thermionic surfaces. Oxide-coated cathode, thorium on tungsten, cesium on tungsten were things that he’d been working with. He had developed into a place where he was in a sense a challenger for Langmuir. And my two pieces of work during the early period, in cooperation with Becker, were a paper on “Thermionic Emission of Tungsten with Thorium Evaporated onto the Tungsten Filament,” and the other paper that we got out together was “Thermionic Work Function and Slope and Intercept of the Richardson Plots.” The theoretical explanation of thermionic emission was very much a question up in the air and was not completely resolved until the new quantum mechanics was applied to electrons in metals by Sommerfeld.
There must have been here a problem of tunnel effect, I suppose.
No, this was not a problem of tunnel effect at all. Actually, Sommerfeld was going to be at a summer school in Michigan in 1931, and I received permission to go out and listen to Sommerfeld’s lectures. This happened to be a very interesting summer at the University of Michigan. In those days, and I think still, any Ph.D. could attend provided he paid his room and board; he had to pay no fee, he was welcomed, in physics. This particular summer Kramers was there, Pauli was there; Goudsmit and Uhlenbeck and Pauli and Kramers were talking spinnors, which later became the spin. Oppenheimer was there. Sommerfeld gave us a very good introduction to the use of Fermi-Dirac statistics to explain the gross features of electrons in metals, and also to aid in a background for an understanding of statistical derivation of the thermionic emission question. The absence of a contribution on the equal-partition basis of the electrons to the specific heat of the metal was a fundamental point there. While some of this had been worked out pretty thoroughly by Schottky during the First World War in Germany, the thermionic emission people in the United States were really not cognizant of this article, and there was a great misunderstanding because of Fowler in his statistical mechanics having stated on one page that he proved that the thermionic work function of a metal could not be temperature dependent; the whole issue was clouded. And while our conclusions from our last paper were not essentially new, nevertheless, we published the paper for clarification purposes, that the work function could have a temperature coefficient.
And this was based upon Schottky’s derivations?
I remember at that time we fully understood Schottky’s paper, though I was aware of the fact — well, the issue of the temperature coefficient of the work function was not primarily raised in Schottky’s paper. It was a question of identifying a quantity that when called the work function from the statistical derivation with a thermodynamic quantity. Was it the heat of evaporation or was it a free energy of evaporation that was involved here. And the thermionic workers, experimental workers in this country, were very much confused on this subject, and this paper was the result of, oh, maybe two or three years thought and many mistakes on the part of Becker and myself and an interaction until we finally clarified it for ourselves and published it, to the further clarification of others.
How did Langmuir feel about this?
Dushman claimed the credit for the statistical derivation in the United States based upon the new statistics, but actually I think Schottky had anticipated Dushman, when you looked up the dates of the papers. But Dushman had no argument with our paper and we were giving credit where credit was due for the previous work, but we went further in the analysis. Langmuir was, oh, somewhat belligerent. We were belligerent on the question of interpretation of how you interpreted the thermionic phenomena when you had thorium on tungsten or cesium on tungsten. He had a concept of induced evaporation. By evaporating the thorium onto the tungsten we could prove that, in essence, there wasn’t any induced evaporation and that the change in work function was not proportional to the amount evaporated on but that there was a dipole effect that decreased as you covered the surface. The rate of increase of work function decreased. About this time, for reasons that I now cannot recall, Becker became interested in the solid rectifiers, such as copper oxide, and selenium. I think part of this interest probably grew out of the fact that there were circuit engineers in the laboratories trying to use copper-oxide rectifiers as circuit elements, modulators. Anyway, about 1933 or ‘34, practically all of my effort went into trying to understand the copper-oxide rectifier. Such questions as to where the rectification occurred, as to whether the rectification was in the oxide or at the oxide-copper interface, or possibly at the oxide-aguadag interface, were not clear. We satisfied ourselves that the cuprous oxide itself, as far as conductivity inside the body of the oxide, was ohmic, strictly ohmic; that the rectification was in the case of the copper-oxide rectifier at the interface between the oxide and the copper. Here, Holden’s mention of tunneling came in as a possible explanation. There was a theory developed for rectification on the basis of tunneling. At this interface it had the wrong sign of rectification.
Whose theory was that?
Oh, I think Nordheim entered into this at one time. Various things went on here. One interesting thing was that when Becker and I thought we had done something that was possibly worth publishing, Walter Schottky working for Schuckertwerke in Germany would just about have, in the next week or so after we thought about this, a paper out, covering some of the ideas. So, he was just about that much ahead of us all the way along during this period. The work suffered for a lack of an adequate theory for experimentalists to interact with, and it wasn’t until the neighborhood of ‘39 or ‘40 that Mott, on the one hand in England, and Schottky, on the other hand in Germany, essentially came out with the space-charge-Debye layer-theory of rectification. And Davidoff in Russia, who had previously tried to make a theory of rectification between two semi-conducting materials, switched horses and joined the Mott-Schottky idea and worked on it also. One other thing though did occur during this period that is of some interest in this context, and that was that even lacking a theory one could see that there was a definite analogy between a copper-oxide rectifier and a vacuum-tube diode.
What was this analogy based upon?
They were both conducted easily in one direction and not in the other. They were both rectifiers. There was even the intuitive idea that somehow work function differences were involved, or the ability of electron charges to flow out of one material and not out of the other. But even closer than that there was, on the one hand, the feeling that there must be some potential hump that made it easier for the electrons to flow one way than the other.
Were you aware at that time of the role that the space charge might play in the solid state?
No, not until the Mott-Schottky theory. We were not competent enough apparently to think of it ourselves, at least we didn’t. But to anybody worth his salt who was working in this area — there were lots of people who were working in this area — this analogy was very obvious, and having this analogy one said, “Ah, if one knew how to put the third electrode in the cold rectifier — like the grid in the vacuum tube-one would have an amplifier.” Becker and I had our period in which we thought seriously about this, even to the extent of calculating (when we later got the Mott-Schottky theory) the size of the grid, the space in which there was available to put the grid and what size the wires of the grid would have to have to fit into this space. And one could figure out that the resistance to the grid would be so large that you couldn’t apply the potential where you wanted to apply it, so that this idea would not work.
It is also of interest here that after Becker and I went through this line of thought and laid it aside, William Shockley, who had recently been hired from MIT at the Laboratories, and for a while was somewhat of a free-lance — he was of the next generation, a generation who had gone through college and graduate school saturated in the new quantum mechanics, not one who had to pick it up on his way along — was particularly adept at applying the quantum mechanics to particular problems. He used to discuss and explain to the older physicists who came before me, who had not even grown up in this period, for whom quantum mechanics was a completely foreign thing, something they could hardly understand. He came to me one day and said that he thought that if we made a copper-oxide rectifier in just the right way, that maybe we could make an amplifier. And I listened to him. I had a good esprit de corps with him, and so after he explained, I laughed at him and told him that Becker and I had been all through this and that this sounded exactly like the same thing, and that I was quite sure it wouldn’t work. But I said, “Bill, it’s so damned important that if you’ll tell me how you want it made, if it’s possible, we’ll make it that way. We’ll try it.” The unit was made, or two or three, to his specifications. I knowing what could be done and he knowing what he wanted, and it was tested and the result was nil. I mean, there was no evidence of anything.
About when was that?
That must have been somewhere between 1939 and ‘42.
By that time, I guess Hirsch and Pohl had made their sodium fluoride check on these ideas.
Yes, you can check that date in there, when they did that. We looked at that paper, yes, but this was obviously not a useful technical device.
Oh, no. That was in December, 1938.
This was in essence a grid. The Hirsch and Pohl experiment was in essence making the space-charge layer big enough in a very poor conductor so that you had room to put a grid in.
And therefore encountered a tremendous frequency limitation.
Yes, a tremendous frequency limitation.
What were the origins of the space-charge layer which Mott and Schottky were talking about — a purely classical electrostatic result of difference in work function?
Yes. Schottky wrote voluminously about it. It was hard to find out exactly what he was thinking about it.
He didn’t write clearly, that fellow.
No. Schottky is still alive, and I’ve met him since, and kind of love the fellow for the competition he gave me all through this period. But it can be said of Schottky’s German: you first have to literally translate it, and then you have to re-translate it to understand what the science is.
Yes, I found that in a paper that interested me.
Well, about this time — some of these things have been written down, but you still want me to talk about them here?
If they’ve been written down then you can discuss them briefly, and then we can perhaps go on.
Well, about this time or somewhere in this time, one C. G. Southworth — I think those were his initials — was working on...
Yes, G. C. …very short waves and wave guides out near Homedale, where he had radio quiet, away from the laboratories. It was still on West Street. And he found that vacuum tubes were not very good detectors at these frequencies, and being an old cat’s-whisker-detector man of early radio days, he decided to go over to the radio market that was still down in the lower part of Manhattan, where you could buy second-hand radio equipment, and look around to see if he couldn’t find somebody that had some of these old cat’s whisker detectors. He found some in a back shelf someplace, dusty, and made a bargain for them, and took them out to Homedale, and found that they would detect these waves. In fact, these waves, it might be of interest to say, were getting into the short-wave region that Hertz originally used to prove Maxwell’s equations. And Hertz may have used in certain cases in his experiments something like a cat’s whisker, in the later stages at least. As a result of this, a man in the group, down at Homedale by the name of R. S. Ohl, decided to investigate these active cat’s-whisker materials.
The most significant ones at the time were silicon and lead sulphide, galena and usually one got action from natural crystals that one picked up one way or another. I don’t know why, but he made the very important, fundamental guess to concentrate on silicon. It was not really the most active; it was less active than lead sulphide as we knew it then. And he encouraged Scaff and Theuerer at the Bell Labs, the same group that had cooperated with us on copper oxide, to see if they could not produce more uniform and pure silicon. On a chunk of silicon at that time, a poly-crystal sample such as you could purchase on the market, you could hunt and you could find occasionally active spots. These spots were of two natures: the rectification would be one way or the other way. But a large part of the surface would be completely inactive. Scaff and Theuerer started making melts of silicon in quartz tubes, and they got to the place where they sometimes would get a whole ingot that would rectify one way, where any part of the surface, would be active, and other ingots in which the whole surface would rectify the other way. And then one day they made an ingot one half of which rectified one way and the other half rectified the other way. And Ohl investigated this surface and found out there was a rather narrow boundary where it changed from one type to the other, and he proceeded to cut out a section, including this boundary, normal to the piece he’d cut out.
Was this a deliberate control?
No, this was accidental.
He merely had noticed that he could produce the one type...
Scaff and Theuerer were making ingots for him, and they were not testing the ingots; they were being sent to Ohl. Ohl had gotten himself some diamond saws and fixed up so that he could handle this material, and he would do the investigating. And one of the ingots they sent him was not either all of one type or all of the other, but of one type at the end of the ingot and the other type on the other end of the ingot. Having cut this section out and made contact to the two ends, he found it was rectified like a rectifier. And this was the first clearcut case of rectification in a semi-conductor, except possibly for some evidence of silicon carbide done by Sears back in the early days with Becker. When we were working on copper oxide, we also worked on silicon carbide. Ohl also, since he worked in a laboratory, might not have made the same discovery in these days with fluorescent lights up there, but in those days one had the ordinary tungsten lamps, and he noticed that this junction was apparently terrifically photosensitive.
This phenomenon, this piece of black material — it’s completely black to look at, looks like coal, more or less — was of course reported by supervisors up the line. It came to Kelly’s attention — he may have been Director of Research then — and Becker and I were invited to a conference in Kelly’s office to discuss the meaning of this phenomenon. We were presumably the physicists who were supposed to know something about semi-conductors. We knew that the copper-oxide rectifier was a photocell, that you could develop a photo EMF in light. We knew the order of magnitude of the photo EMF you could get in room light. We also knew what it was for selenium. These were then the two things we used for exposure meters. And we were completely flabbergasted at Ohl’s demonstration. The effect was apparently at least one or two orders of magnitude greater in room light than anything we’d ever seen. And moreover, it was obvious that he was illuminating this boundary on the edge whereas with all the other cells one took a great effort to get the light spread out over the boundaries through semi-transparent, thin films, and also the thing was obviously opaque in appearance, to the eye. I even thought my leg, maybe, was being pulled, but later on Ohl gave me that piece or another piece cut out of the same chunk, so I was able to investigate it in my own laboratory. I still have the curves around.
How big was the piece?
Oh, it was about a half a centimeter on the side and about a centimeter and a half long. The junction was very definitely in the center and you had contacts on the ends.
Was the junction visible?
Under the microscope and with proper etching, yes, that is in future studies; I don’t know whether that one was so etched then that you could see it. So, it was PN junction, as we now call it, the first one I ever observed that was clearcut.
About when did this happen?
I was looking up that date, and I think I wrote it down — around 1939 or ‘40. Of course, the Second World War was approaching very fast at this time. Radar, of course, was in concept in the offing to the English and people at home now. Some knowledge or some application of our knowledge to help them prove the silicon point contact detector for centimeter waves, 10 centimeters to one centimeter waves, was very urgent. And as a result of this, Becker and I undertook a program to study this phenomenon. It was obvious this was the same thing as a rectification of copper oxide — to study this phenomenon in silicon. And actually sometime in ‘41 I made some rectifiers which I tested at low frequencies, 60 cycles, in my laboratory, and then was warned that any tests I did at these frequencies would have nothing to do with what they would do at microwave frequencies and that I’d have to ultimately test them there. But this was before the war, and most physicists before the war were DC physicists, when they still had galvanometers. About as far as the physicists could go was 60 cycles, and maybe audio-frequencies, yes, with Hewlett-Packard oscillators in the laboratories. I took them down to Homedale. One of these became the low-noise standard throughout the war at Homedale. I, at least, convinced them that I knew enough about the physics of it so that I could have some concept of how they were going to work at microwave frequencies from what I could do at 60 cycles.
Now, these that you made were again PN junction rectifiers?
No, these were point-contact rectifiers, made in a form so that they could put them right in their wave guides.
I suppose your interpretation of Ohl’s PN-junction rectifier must have been that there was a difference in work function on the two sides of this boundary.
We knew it was P and N type. Oh, yes, we knew this, because the difference in sign of rectification; we knew there were holes on one side as in copper oxide and it was electrons on the other side as in zinc oxide and in some of the others. The two types: defect and excess conductivity were names in the technology at that time.
H. A. Wilson, I guess, had ironed that out.
Yes, I should have mentioned H. A. Wilson. What Wilson had offered, that came before Mott and Schottky, was the model of a solid which could be either an insulator or a semi-conductor. Mott and Schottky’s theory came after H. A. Wilson. The emphasis was, however, in this case on the chemical reaction between the impurity that gave up by ionization in the lattice, the extra electron, the energy necessary to ionize that, and there was a complete neglect of the more fundamental question: the ionization of holes and electrons in a pure lattice.
Now, this was one of the blind spots that was mentioned in that paper.
Yes. Not long after this we entered the War. The Japanese hit Pearl Harbor when I was sitting one Sunday working in my apartment; I’ll never forget the day. There were jobs of great urgency, and one of these was considered to be magnetic detection of submarines, and I was loaned to this group. Science, of course, ceased, and we proceeded to do engineering with our knowledge. The work, though, in this area went on during the war under secret classification. Scaff and Theuerer and the metallurgists at Bell Labs, and I guess Ohl, and outside people, a group from the University of Pennsylvania and from MIT — Bethe came in on it. And he rediscovered the explanation that Becker and I didn’t think pertinent enough to publish as to why a point contact on a semi-conductor would detect to higher frequencies than copper oxide would if we just reduced the size. In copper oxide we reduced everything uniformly; you did not change the frequency limit at which it would quit rectifying by reducing the size.
By reducing it uniformly, do you mean making the size of the rectifier smaller?
Yes, the whole part of it. The point was here that the limit of rectification at high frequencies was determined by the capacity across the rectifying layer and the forward resistance, and the lower you could get the forward resistance, as compared to the capacity, the higher the frequency the unit would operate at. And when you made a point contact to a large area of a semi-conductor, the forward resistance was determined by the spreading resistance. The smaller the radius, the higher the resistance, but it was proportional to the radius of the point. The capacity on the other hand was proportional to area or the square of the radius of the point. So that by going to very small radii, you could reduce the effective capacity faster than you increased the resistance in the forward direction and, therefore, you could rectify at higher frequencies. Let’s rest a minute. Well, I left to go on this other work during the Second World War. Scaff and Theuerer, the metallurgists, were then working on silicon and carried on. Just before I left, I was aware that they were of the opinion that the PN-junction was due to differential segregation of impurities as the melt cooled, giving more of one type of impurity at one end of the ingot and more of the other type on the other end. And I was also aware, I think before I left, that by using their noses to smell the ingots as they came out of the furnace they finally traced one of the impurities down to phosphorus, a fifth-column element, tracing it back to the smell that you used to have in the old carbide automobile headlights, and finding that that smell was due to an impurity in the carbide, namely, phosphorus. By their noses they were detecting concentrations of phosphorus way below the spectroscopic limit.
Did this mean that henceforth they were able to produce these N and P types at will after they had realized the role of phosphorus?
My part of the story has to come back after the war. I returned to the Bell Laboratories from this war job, which was under contract to Columbia University and actually under the direction of my old Professor Tate. This NDRC contract was originally set up at the instigation of Tate and Fletcher.
Is this Harvey Fletcher?
Yes. And he’d remembered some of the difficulties that we’d had with submarines in the First World War, and when they saw sometime in 1940 what trend things were taking, they went to the Navy and suggested we ought to set up some new work on the detection of submarines. The Navy scoffed at the idea; they said they knew all about submarines from the last World War, they didn’t need this work. Tate and Fletcher were actually influential enough and stubborn enough to set this work up. And as a result of this they set it up under what was then called the National Defense Research Council and not under the Navy. When I entered the program one of the interesting projects was using sensitive magnetometers to detect the magnetic anomaly of a submarine in deep water. But by the time we got something practical developed the submarine war was over due to other devices. This had a very distinct result, however, upon me and probably on most physicists. During World War II physicists became AC physicists as well as DC physicists and came out of this knowing some circuit theory.
I got my first introduction to Campbell and Foster during this period, the Fourier transforms. My chief job was the design of the magnetic head. A biophysicist, who was a genius at electronics, designed the electronics of our equipment, and a mechanical genius designed the mechanical side of the magnetic detector. But in ‘43 the submarine war was over and there was no longer high priority here, and I came back to the labs and worked in with Becker on the using of thermisters, another form of semi-conductors that had come through J. B. Johnson’s group in the Labs and was represented by G. L. Pearson, a friend of mine, to detect for infrared as a war device. Becker’s group had gotten rather large. During the war nobody was switched around in the Laboratories; you nominally reported to the same person that you reported to before the war, but different ones of the executives took interest in different fields. While you might be reporting to one, your work might lie under the direction of another; it was divided up and they didn’t take time to reorganize. And as a result of this, it was decided towards the end of the war to put all of Becker’s group and apparatus into Development, out of Research. When I was told about this I was first told that I could go back to Research after the war was over before they told me what they were doing to me, because they knew I would yell. And then somewhat later a list came around on my desk of a new group that was being organized to do research in the solid state. The heads of this group were to be joint: S. O. Morgan and William Shockley.
I read through this list and thought about it a minute and read through it quickly again, and I said, “By golly! There isn’t an s.o.b. in the group. Some group.” Then after a minute I had a second thought that maybe I was the s.o.b. in the group. Anyway, somewhere in late ‘45 the war was sufficiently along in all areas, and this group was pulled together, and one part of this group’s work was to try and see if we could make some progress at understanding the essential physics of semi-conductors. Pearson was a member of the group, and he and I were probably the two experimental men in this area. Pearson’s past had always been a concern with the body properties of the semi-conductors far from the surface, and mine of the surface properties where the active rectification or photo effects occurred. This group was called together, as we often did from then on, and the whole question of what had been the bottleneck to essential physical understanding of semi-conductors was raised. Why, with all the work that Schottky had done and that we’d done before the war and that others had done in Russia and in England, Germany and France, hadn’t one gotten to a better and true understanding of the processes. And the answer was that the semi-conductors that had been worked on were essentially very structure sensitive, extremely complicated and dirty phenomena, and that it was practically impossible to sort out the complications.
The next question was what are the simplest semi-conductors, and the answer to that question was silicon and germanium. Germanium had come out of this war work, in the secret group, as a similar semiconductor to silicon — simple covalently bonded solids, by the now well-understood hydrogen bond from quantum mechanics — probably the simplest solids that existed, and furthermore they were elements. What we may not have realized immediately that day, this covalent bond being the type it was, was that it is almost impossible for there to be vacancies in the lattice. Any impurity would have to be another element and therefore easier to detect, measure and specify. The decision was made then by the group, in a sense, or at least it was a unanimous decision, that the thing to do was to study and try to understand, first, silicon and germanium. From the metallurgical group we could get and obtain samples of either silicon or germanium, polycrystalline to be sure. But in the case of germanium we could specify the specific resistance and the type and get samples that came within 20 percent of these values. This was also the case for silicon, provided we didn’t ask for too high a resistance. And this is where we took off.
Shockley, meanwhile, during his war work when he was doing other things — had thought some more, and based upon the Mott-Schottky theory of rectification in which presumably the space-charge layer in the semi-conductor was being induced by the contact potential field between the semi-conductor and the metal contact, said, “If the contact potential field will produce a space charge layer, then an applied electric field should also produce a space charge layer, and therefore one should be able in principle to make an amplifier.” This was the so-called Field Effect Amplifier; because, by applying a field through a capacity to the surface with very little current flow, one could in a thin strip modulate the conductivity lengthwise of the strip by changing the depth of the space charge layer. The only trouble was that one could calculate how much modulation of conductivity which one should get on silicon and for a given field, and one did not get this modulation.
The other thing predicted on the basis of this theory was that the contact potential between an N and P type piece of silicon should be large and predictable. Experimental measurements of this contact potential gave practically zero. There were a series of several effects that are written down carefully in the report you have, that were recognized to be discrepancies with the then theoretical picture. The theories did not explain these experimental phenomena. In the group one gradually recognized that these various unexplained things were related, and that if we found the explanation to one, we’d find the explanation for all of them. The absence of Shockley’s predicted field effect was one of these things, and contact potential was another. I’m trying to recall for a minute where we were. Oh, yes, the next step was the suggestion by John Bardeen that the concept of a free surface of a semi-conductor being electrically neutral from the first row of atoms in with the work function dipole completely concentrated in the first layer, or near the first layer of atoms, was after all very naive. And in the sense that a semi-conductor was like an insulator, at least to the extent that charges had to be thermally excited, there was no reason why you couldn’t charge the surface of a semi-conductor, that there could be states in which charges could reside on the surface.
What was it that brought Bardeen to this new idea?
Surface states had been considered before as a theoretical possibility of extra states, as well as the concept of a solid in which the atomic states around each atom or nucleus, would lose their character and become properties of the crystal. And in the interior of a crystal, presumably there’s a state in the band structure of the crystal for every atomic state of every atom. But when you come to the boundary, it may well turn out that some of these states are left over, and for the boundary conditions that you may postulate, if they are not taken care of in the band structure of the solid, they will have to be extra states on the surface. Now, these states, of course, would be filled as a result of temperature, temperature excitation, and there would be thermodynamic equilibrium at any particular temperature. If it turned out that the condition of filling of these states on the surface did not correspond to electrical neutrality on the surface then of course for there to be complete equilibrium there would have to be an adjustment of the potential of the surface with respect to the potential of the interior, and an equal and opposite induced charge in the space-charge layer. And therefore one could expect on a free surface of a semi-conductor before metal contact was made to a space-charge layer that it was an inherent property of the semi-conductor and its surface; it had nothing to do with the metal contact that was made.
And if these states were of sufficient density, surface density, regardless of whether the interior was of N or P type, you could predict that there would be no contact potential difference between an N and P type sample, which was an experimental fact. If these states were of sufficient density and the equilibrium between the interior and the states could occur fast enough, you could predict no field, electric field, would penetrate that side, that the electric field would end on charges in the surface states, and the space-charge layer inside would be screened from the field. In other words, in one fell swoop most of these difficulties were explained away, and we had a model on which to work. And in one of the first sessions of the group that was called together, in which Bardeen presented these ideas to the group, two experiments were suggested: one was Shockley’s suggestion that if the surface states were not too dense, that then as you dope a crystal N or a P type, the potential should pull away from its value on high purity crystals, and that maybe with doping you should begin to get a contact potential difference between highly-doped P types and highly-doped N types. And then if one could measure such an effect, one could estimate the density of surface states.
The other suggestion was mine, which involved suggesting that if there was a space-charge layer on the free surface of a semi-conductor and if you produced extra hole electron pairs in this region in which there was a field, the holes would tend to go in the field one way and the electrons would tend to go in the field the other way, and as a result, you would induce a charge on the surface due to the illumination of the surface which would amount to a change in contact potential. At that time I had a system whereby I was measuring contact potential. It was agreed in the group, as often when we discussed these things, there was one obvious person to do the experiments and I was the one to do these, and I did both experiments and both experiments were successful and published.
One of these was of the pure material and the other one was…
Well, I just took an N or P type sample, illuminated it, measured its contact potential, and saw, as quickly as I illuminated it, the contact potential changed. Contact potential is a very simple experiment, a Lord Kelvin experiment, where you move two conductors with respect to each other, changing the capacity; if there’s a field in there, you’ll change the charge. So, if there’s a contact potential, there’s a field in there, and you change the capacity and you can detect the charge flow. And then you substitute another potential and you find the potential at which no charge flows when you change the capacity, and that’s the opposite of a contact potential. And, of course, we were doing this on an AC basis; by now we were AC physicists. We make the capacity change sinusoidally all the time and amplified the AC signal that came out.
So, your instrumentation, too, had changed considerably.
I never did a contact potential experiment without doing it this way. In the old days you had a quadrant electrometer, you had plates a certain distance apart, and you suddenly moved them to a different place and measured the accumulated charge on the quadrant electrometer. It was a difficult and time-consuming experiment. In this case, I had a continuous on-the-scope observation of the contact potential which was in a sense a phase-reference detector. R. H. Moore, who was an electronics design man, joined the group and made equipment that I still have. He gave me a factor of about 10 more sensitivity using a phase-reference amplifier, because one was only interested in the signal that was in phase with the change of the capacity. And proceeded to get various samples of silicon that were of all degrees of doping, from very extreme N type to very extreme P type. I found very little difference in contact potential in air, but found that on sand-blasted samples in a vacuum I could find a change of contact potential in doping. I also tried various surface treatments — some of the treatments were very random — the results were not sufficiently consistent to warrant any conclusions.
But, at least, there was evidence that on a certain type of surface in a vacuum there was an effect to which we could put an approximate number for the density of surface states per volt, on the order of about 10 to the 12th, I think it was. A further experiment that we wanted to do in order to get at some idea of what the magnitude of this potential across this space-charge of Debye-layer was could we possibly measure a temperature effect. And so, I started to set up this vibrating electrode on a long stem so that I could stick it in a thermos bottle — I don’t know whether I was working with silicon or germanium at that time, though, I think, I was largely working with silicon. I made such an experiment, cooled it down by — I’m essentially a lazy physicist: if you’re going to change the temperature, let’s change it a lot — and I got changes in contact potential as it cooled down and changes as it came up.
But it was obvious that I had a great big hysteresis loop, and in examining this loop a little bit, it was obvious that I was cooling it down, the walls of the vessel surrounding the sample were the coldest and I was condensing the moisture in the air on those walls, drying out the sample in essence, and when I was warming it up, the sample was the coldest and the moisture was going the other way. I don’t know, but I think quite definitely future results indicated that this is what was happening. And so I toyed around in my mind: How can I do this experiment — I was still being lazy; of course, I could have evacuated the thing, but that was the sample that had been fixed up to put down in this thermos and it wasn’t exactly conducive to evacuation; and it would have taken some time to make this. Still being lazy, I got the idea that maybe if immersed the system in a dielectric liquid I could still vibrate the electrode in the liquid and I could measure the contact potential. There was no reason in fundamental physics why I couldn’t, and if I got the surface in equilibrium with the liquid, maybe I could get rid of this hysteresis effect (maybe the surface would stay in equilibrium with the liquid and I could eliminate the moisture effect). And then I realized, of course, that the higher the dielectric constant, the more sensitive things would be, since I’d started to do a little theoretical thinking.
So, I started looking up dielectric constants, and of course electrolytes have dielectric constants, it was not too clear in some handbooks as to whether liquids were dielectric or an electrolytic. Water had a very high dielectric constant. I knew water had some conductivity, but anyway I tried a lot of liquids after doing a little looking up. As far as my apparatus was concerned, I had two classes of liquids: one in which I could still measure contact potential, and others in which I could no longer measure contact potential. I could vibrate the electrode all I wanted to and there was no evidence that there was a change. So, of course, I had all this in my contact potential apparatus, and whenever I could measure a contact potential — I’d always have a balancing voltage in there: I’d always keep it set automatically at the voltage that would balance the contact potential out. I, of course, was aware of the change in contact potential in light at this time, having discovered it myself, and the experimental apparatus was arranged so I could observe this effect. So I noticed with these liquids that I had enhanced photo EMFs. In fact, I spent some time running through a few liquids. Then I was completely flabbergasted.
Which liquids, Walter?
Well, I had dielectrics and I had electrolytes. There are the two kinds. I was willing to show these phenomenal effects — I had photo effects that even at the time looked to me bigger than the PN junction — we’ve talked about this before. Finally, I was demonstrating these things to anybody in my group that would listen, and one fellow who joined us when this group was organized was Gibney; he was a physical chemist who was brought into the group purposely. I was showing these effects to him and, of course, he was a physical chemist and knew something about electrolytes and he said, “Wait a minute. You’ve got a potential on there, haven’t you?” I said, “Yes.” He said, “Let’s vary this potential just a bit.” So, he varied it, and in the case of water or an electrolyte, we found that we could vary the photo EMF from anywhere to a very large value to zero and change its sign. With the dielectric liquids we found that we couldn’t do this. And I have written up in the notebook as specified in the story that you’ve got there that Gibney and I had by the use of the electrolyte modulated the space-charge layer. The field effect had finally been accomplished. We had another session in which this was discussed among the whole group, and they accepted this interpretation of it and that we were told to write it up. We had it witnessed and we even discussed its use as a possible field effect amplifier.
May I ask one question? In Gordon’s report, which says, “In the experiments involving electrolytes, Gibney suggested changes in the DC bias which have been incorporated in the study to counteract that contact potential. The results indicated that the electrolyte was transmitting a strong electric field to the surface layer of the silicon.” What do they mean by transmitting a strong electric field?
Well, you see, “to the space-charge layer,” in the more technical language, before the field only occurred between the surface of the silicon and the plate. The surface states were shielding the surface. In this particular case, as we now know — after much work we know even better right now than we knew then — the electrolyte was in its anodic action, on the surface, removing the surface states. In fact, a colleague of mine, Boddy and I — have a germanium surface in an electrolyte in which it’s impossible to find any surface states. But as we thought at that time, with the fact that all the potential drop between the electrolyte and the inner face occurs if the electrolyte’s reasonably concentrated in a very short distance, you can create very high fields with a very small potential difference. We thought then maybe we were getting the field high enough to overcome the surface states and induce a charge in the space-charge layer. Well, it was some time after this — what was the date of that?
That was November 17, l947.
It was shortly after this that Bardeen walked into my office one morning, suggesting a geometry in which it might be easy to modulate the space-charge conductivity, and thereby make an amplifier. And the geometry was essentially one of taking a point contact, somehow insulating its surface, and putting the point down on the semi-conductor surface, and then surrounding it with a drop of an electrolyte to which we made contact with another metal, thus hoping to modulate the flow of current from the point to the semi-conductor by an electric field through the electrolyte. I can draw it but it won’t go on here.
I think I’ve got it clear in my mind. Here you have an insulated contact, and then you have a drop…
The contact is not insulated from the semi-conductor but insulated from the electrolyte.
And then you had a probe in here?
In the electrolyte, making contact with the electrolyte.
Is this a wire probe of some kind?
Yes, I think I suggested — I wouldn’t know now –- “Why, John, we’ll wax the point.” One of the problems was how do we do this, so we’d just coat the point with paraffin all over, and when we’d push it down on the crystal, the metal will penetrate the paraffin and make contact with the semi-conductor, but still we’d have it perfectly insulated from the liquid, and we’ll put a drop of tap water around it. That day, we in principle, created an amplifier. This is the field effect. This is just a geometry to make use of the electrolyte and to actually create the field effect. The water drop — which we played with the whole first day — got to be a nuisance. Just as we would get things operating right, the drop would evaporate, and Gibney came with a suggestion that we use the glycolborate that they use in electrolytic capacitors. And thereby hangs a tale, in a sense. We used the glycolborate and it was very satisfactory. It wouldn’t evaporate, and we could use it for long periods of time.
I’d have to check on that, but we started out with one type of silicon. John, of course, was very intimately involved right in the lab. We switched from silicon to high-backed voltage germanium. We had the effect, we knew the sign, we knew what the signs should be if it was similar to the silicon but high-backed voltage germanium, we got the opposite sign. I turned to John and said, “How do we explain this?” Well, this presumably was an inversion layer. While the interior of the sample was N type, the space-charge layer was so large that the surface of the germanium was P type, and the flow was by holes in the neighborhood of point. And therefore it took a different sign of the field to give us the effect. And in the process of working with this, we found that if we put on some steady bias on the electrolyte, in addition to our A.C. signal we got a bigger effect. This bias was in the anodic direction, and we could see through the glycolborate that we were anodizing the surface growing visible interference films, green film. I can remember the green color under the glycolborate. We were unable to make the thing amplify much above 10 cycles. We reasoned that this was the slowness of the response of the electrolyte, and in those days, we figured the only thing to do was to get rid of the electrolyte. I know now that we could probably go to very high frequencies with the proper electrolyte. It was glycolborate that was slow. So, seeing this film, we thought, “Ah. This oxide film must be insulating. If it is, we can form the film and put metal electrodes right on top of the film, get this field effect without the electrolyte and get the higher frequencies.” My vacuum apparatus which could have been used for an evaporator was tied up with the contact potential equipment in it. Gibney had another apparatus in working order: he had been evaporating some metals for other purposes.
So, we took one of these samples and anodized it, designed the mask so that we could put on a circular piece of gold with a hole in the center, washed the glycolborate off, and set it up so this apparatus was ready to go and immediately put it in the apparatus, and it evaporated the gold or, the surface. Gibney took it and did this and brought it back to me, and I started to investigate it. I inadvertently shorted the point to the gold film in the nice center hole so I got practically no data there. I was disgusted with myself of course, but decided there was no reason why I shouldn’t go around with the point on the edge of the gold to see if there was any effect, even if the gold was covering only part of the surface. I got an effect of the opposite sign. I got some modulation, yes. The germanium oxide formed by an anodic process is soluble in water, and when we washed the glycolborate off, we washed the oxide film off. We had a very specially chemically etched germanium surface on which the gold was evaporated, just right to make a very good emitter. When we put a certain potential on the gold, we were emitting holes into the germanium in such a way as to modulate the conductivity through the point when it was biased in the reverse direction.
A completely unexpected result.
Oh, yes. Nobody had any concept of this. And after discussion with John Bardeen, we decided that the thing to do was to get two point contacts on the surface sufficiently close together, and after some little calculation on his part, this had to be closer than two mils. Most of the wires that we were using for point contact straight down on the germanium surface were pointed, but the wires in general were at least five mils in diameter for strength, and how you get two points five mils in diameter sharpened symmetrically, closer together than two mils without touching the points was a mental block. I accomplished it by getting my technical aid to cut me a polystyrene triangle which had a small narrow, flat edge and I cemented on a piece of gold foil, some of the prewar gold that I still had around. And after I got the gold on the triangle, very firmly, and dried, and we made contact up to it at the points of the triangle, I took a razor at the apex of the triangle and very carefully cut a thin slit, I could tell when I had separated the gold. That’s all I did. I slit carefully with the razor until the circuit opened, and put it on a spring and put it down on the same piece of germanium that had been anodized but standing around the room now for pretty near a week probably. I found if I wiggled it just right so that I had contact with both points that I could make one point an emitter and the other point a collector, and that I had an amplifier with the order of magnitude of 100 amplification, clear up to the audio range.
You say John Bardeen calculated that you had to have a separation as small as this and I was a little surprised that he had the means for making this calculation, because as we would now do it, I suppose that this depended on the lifetime of minority carriers.
And I would have thought that this whole idea of injection of minority carriers in their lifetime wasn’t clearly in hand at that time. Is this true?
John Bardeen knew what the Debye length was for example. He probably knew or could estimate the photo response, maybe that it might be of this order of magnitude or another order of magnitude. John Bardeen was great at coming up with approximate guesses of this kind and making the right guess.
Was it clear then at once that what was happening was the injection of minority carriers?
There was a period in which one was not sure whether these holes were flowing in the space-charge layer or whether this was radial injection into the crystal. That was later essentially demonstrated by putting one point on one side of the thin wedge and the other point on the other side of the thin wedge and still getting transistor action, in other words, by the injection of holes on one side of the crystal modulating the conductivity on the other side. The geometry of flow around these points — it’s hard to distinguish whether you’ve got a spherical flow or a surface flow. The two geometries are not essentially different. Becker and Shive did this! Of course, after demonstrating this a little bit and after the people got the idea of cutting chisel edges on the wires and letting them come in sideways — well, I guess H. S. Black of our laboratory, of feedback fame, was the first one to make one for himself, and, under some company security, things were booming. John and I proceeded to get built a micro-manipulator so that we could, under the microscope, place these chisel-edges at different distances at will. We could etch a germanium sample and pick out what seemed to be a rather large crystal, (we soon found there was a crystal boundary effect) so that we could measure the drop-off of the effect as the function of distance, the induced potential on one point due to putting the potential on the other point, trying to understand the physics.
We did a lot of work of this nature, but the cat was out of the bag. So much was it out of the bag that when we finally announced it to the press in July of l918, the various hams and other amateurs around the country, would just buy a germanium diode and make themselves a transistor. it is of interest to those that ask whether we knew how important this was that the evening of the first day, when John had come in and suggested the geometry, I told my riding group that night, going home, that I felt that I had that day taken part in the most important experiment I had ever taken part in my life. And the next evening going home with them I had to swear them to secrecy. This was even before the transistor was discovered. Well, I am quite humble about my part in all this. I almost have a mystical feeling about the fact that the final discovery of the transistor, in a sense, waited for me. The various steps and pieces of information were not kept secret from the research group of which I was a member, and in which we had very good rapport. It was probably one of the greatest research teams ever pulled together on a problem: Pearson doing fundamental experiments with Bardeen on the body properties, coming out with the idea that a proper thing to measure of a semi-conductor was how the product of the holes and electrons varied with temperature, not how the holes or the electrons varied with temperature.
Actually, I had the flu for a week after the first experiment with John, then came back and went on with the work. Another evidence of how important this effect was recognized almost immediately was that at each level of supervision, when they were informed, there was hesitation about informing the next level for fear an announcement of such importance turn out to be a fluke, and that our faces would be red for prematurely claiming something so important. And I’m not sure, but I think it was probably almost a month before M. J. Kelly, who was then the Executive Vice President of Bell Telephone Laboratories, knew what was going on in his organization. I cannot overemphasize the rapport of this group. We would meet together to discuss important steps almost on the spur of the moment of an afternoon. We would discuss things freely. I think many of us had ideas in these discussion groups, one person’s remarks suggesting an idea to another. We went to the heart of many things during the existence of this group, and always when we got to the place where something needed to be done, experimental or theoretical, there was never any question as to who was the appropriate man in the group to do it. You, Holden, may have been in the group when we were discussing the question of whether the man in California actually had super-conductivity in liquid ammonia, and we worked to the heart of that problem. And they chose Pearson, or Pearson volunteered in a sense, as being the proper man to do the experimental work. But first, after a couple of meetings on the subject, we went specifically to the key experiment before we did any work.
Yes, that kind of discussion was enormously useful in that group at that time, as it must be in any group. Another thing, of course, which has impressed me with your account, and with my recollection of how things went and with the way my own work has gone, as a matter of fact, is the extent to which the work profited from the availability of people like Scaff and Theuerer in the metallurgic department and Gibney from chemistry, the cooperation from so many different fields of specialization. It’s so hard to get in a university, and so beautifully available in Bell Laboratories.
There’s no question but what you’re absolutely right in this respect, and when later on three of us were separated out of the group and honored, as we have been, it was with considerable humility that we thought about the fact that we had, as our sponsor in Stockholm said, literally stood upon the shoulders of others.
But I think that none of the people who participated in that would think for one minute that you were not the people who deserved the honor.
would like now to go back and bring out certain things that since starting this I’ve thought of. I think as far as my meager competence as a physicist is concerned, it is significant that my maternal grandfather was a flour miller by trade, that my paternal great grandfather, Andrew McCalley was also a flour miller by trade, I spent considerable of my youth — a lot of years of high school and while I was at college — in a flour mill run by my father, that I could take a Dodge engine of that vintage apart and put it together, and did so on my vacation, that when I was at Moran School on Bainbridge Island in my senior year of high school I volunteered to run the diesel engine that powered the light plant of the school, and I used to take it apart and fix it up when it broke down. It is also of some interest, which I forgot while discussing those early days, that there was a physics professor at this school who did inspire me somewhat and was my boss as far as running the diesel plant was concerned, a man by the name of Yates, who was also a graduate of Whitman College and a student of Brown’s.
This man Brown was some man.
I also think it significant that both my grandfathers crossed the plains, one in 1852 and one in 1854. They were pioneers. My mother and father were born in the Territory of Washington. And, of course, I think it’s also significant that they both had a college education. In the case of my father, he worked his way through high school in Spokane as a photographer’s helper, then worked his way through college, thrashing in the wheat fields and one summer running a pack train for the U.S.G.S. Survey that surveyed the Idaho-Montana line in the Bitterroot Mountains.
I derive from this the significance that it is of very great help to do many things and get confidence in one’s own ability to do things.
Well, actually, I was almost an unsocial creature when I went through my senior year at high school and when I went to college, because I had spent one whole year before this herding cattle in the mountains, with a rifle, my own camp. I only saw my family on occasional weekends and saw practically no other individual outside of my mother and father and brother and sister. I was self-reliant, I felt perfectly capable of handling myself in the open under almost any conditions or in any weather, but I was not particularly a well-adapted social individual. Well, enough of that. My family background is a matter of record. My father has written a lot of it down and it’s available if anybody wants it. There’s another aspect that we passed over here, in that among the members of what would probably be called the research area of the Bell Telephone Laboratories back — it must have been around 1935 that this started, wasn’t it?
Just about 1935 we wished to educate ourselves, some of us, further than we had in our formal education, and I think the first idea was that it might be well to study the book, Mott and Jones on The Theory of Metals, and we decided to set the thing up on the basis, at first, that certain ones of us would take part in the discussion from time to time of the book. But it was decided on pressure from others in the laboratories, clear into the metallurgical group — Ellis was in this group at the time — to allow listeners, and we ran this seminar, as you might call it, as I remember, one night a week, after work, for about three or four months. And then the thing finally dragged out and stopped. After summer vacation the group of us who had been leading the discussion decided that this had not been a complete success and that actually if we wanted it to be good, if we wanted to get out of it what we wanted, the thing to do was to have a small group in which only those who agreed to take turn in leading the discussion were allowed to be members of the group. This group finally turned out to be approximately eight. Let’s see if we can name the people. Fisk was a member of the group. Woolridge was a member of the group. Foster Nixs was a member of the group. Teal was a member of the group part of the time, I remember. Allen, Holden, Addison White, and Shockley. I think Howell Williams for a part of the time was a member, and myself. I’m not aware of having left anybody out. That makes nine. The actual personnel of this group may have changed from time to time. We first went back and went through Mott and Jones again thoroughly. I cannot tell you quite the order. Having done that one winter, another winter we picked up Tolman’s Statistical Mechanics, and went through it.
That one took us two years, as I recall it.
It took longer than a year, I know. And that was really an experience for me, to realize that when you came to the quantum statistical mechanics, some of the old attempts to prove certain theorems that were not really proved in a good logical fashion and were not necessary when it came to the quantum statistical mechanics. Another year we went through Pauling’s Chemical Bonds, and still another time we went through Mott and Gurney, and unless you can remember some others, that was it.
That was it. As I recall it, Mott and Gurney was interrupted by the war, and Chemical Bonds came after the war when we all got back together.
Yes, this is right. We started over again and went through it again. I always enjoyed being a member of this group. I was impressed with the fact that not all members of this group were Ph.D.’s, some were only A.B.’s, but they all carried their weight in the discussions, and all members were equivalent at least to a Ph.D. in intellectual capacity. Now, that’s about it. An amusing anecdote here is that I was of course a member of the Bell Telephone Laboratories when the announcement came in the newspapers –- radio was not such an important item in those days –- that C. J. Davisson had been awarded the Nobel Prize for his experiment proving the wave nature of electrons, along with George P. Thomson of England. In those days the press did not show up until the day or two days after the announcement and the mechanics of the press was to make a movie for a news release in the movie theaters, and it was immediately evident that Davisson was going to have to have a place that could be fixed up to look like his laboratory. He had not for some time done any work in a laboratory and had not place to call his own. And in my laboratory, where I was working with Becker, under Davisson by the way, there was an alcove running off of a large room that was very suitably adapted to the purpose. The movie cameras could be set up out in the large room, looking into the alcove. And then we fixed this alcove up as Davisson’s laboratory, and the day the movie people and the press were there -– of course, it was my laboratory and I was on the spot, standing around watching everything and seeing that there were no loose ends, probably, as my father used to tell me, with my hands in my pockets and my mouth open –- Davisson, of course, was sweating under very intense lights while they were taking the movies, and was occasionally allowed to rest and come out in the cooler air of the large room and smoke a cigarette. And one of the times that he did this, he took a look at me as I was standing there taking it all in, and said, “Don’t worry, Walter, you’ll get one someday.”
Davy was usually right, and he certainly was in that case.
Of course, I would have sold my rights to having any such thing very cheaply at that time. I had no idea that I would ever be in a similar position.
February 10, 1902, Amoy, China.
Brattain's Ph.D. thesis under John T. Tate.
Wallace R. and Robert B. Brode.
John Zeleny was at Yale; Anthony Zeleny was at Minnesota.