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Interview of James Findley Black by Joan Bromberg on 1985 January 16,
Niels Bohr Library & Archives, American Institute of Physics,
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Summary of work and development of light emitting diodes (LEDs) and diode lasers done in the 1950s and early 1960s at Sylvania Research Laboratories, and at General Telephone and Electronics Laboratories, 1961-1964. Semiconducting Compounds Group investigates intermetallic compounds, especially GaAs and HgTe in the 1950s. Group joins the Battelle Memorial Institute group, 1957. Group effort devoted to GaAs from 1958. Group leaders discussed, Don Wahl, Henry Minden, and Sumner Mayburg. Work prompted in part by Heinrich Welker's 1952 report on preparation and properties of III-V compounds. Description of research proposals, notebook entries, reports, and memos pertaining to invention of GaAs laser, GaAs diffuse diode lasing, 1961-1962, and the cylindrical GaAs laser diode, 1963; GT&E activity in light emitting diodes and laser diodes reduced by 1964. Also prominently mentioned are: K. Arnold, J. Birman, R. Harrigan, Paul Keck, M. J. Massoulie, J. L. Pankove, B. Smith, and Otto Weinrich.
The year 1961 was an important one for the purposes of this narrative because most of the experimentation that led directly to the efficient generation of "'light" from GaAs diodes, and the proposal that lasing could be made to occur in a forward biased GaAs p-n junction, happened during this period. Unfortunately, the year 1961 is one in which we have not been able to turn up much in the way of qualified documentation, such as notebook entries, reports, memos, etc. Below is a description of such documentation as we have been able to uncover.
March 1961: "Direct Recombination in GaAs and Some Consequences in Transistor Design" by S. Mayburg, was published in Solid State Electronics, Volume 2, pp.195-201.
July 1961: A paper "High Frequency Base-Transport Factor and Transit Time of Graded-Base Transistors by S. Mayburg and B. Smith was submitted to IRE Transactions. December 1961: An entry in S. Mayburg’s notebook Y236 on page 94 dated 12/5/61 describing the invention of a GaAs laser. A number of entries in H. Lockwood's notebook B217 pages 10 through 13.
In these entries, Harry Lockwood confirms the writers recollections that the observation of what latter turned out to be highly efficient generation of infrared radiation from GaAs diodes, was the result of experiments to identify the cause of premature reverse-bias breakdown in GaAs p-n junctions. In these experiments, an infrared convertor called a snooper scope was used to render the room temperature junction radiation visible to the eye. It was expected that areas which showed little or no infrared light emission under forward bias would be those areas in which the cause of premature breakdown would be found S. Ku's remembrances of events leading to measurements of light emission in GaAs revolve around studies of varactor diodes at low temperature. She recalls operating a GaAs varactor diode in liquid nitrogen to study the expected improvement in device properties, and observing faint red light coming from the device under forward bias. Entries on page 15 of H. Lockwoods notebook do record the observation of visible red radiation at liquid nitrogen temperatures an 1/18/62.
Other points of general interest that proceeded from our Joint points of general interest that proceeded from our joint discussions are: Sometime in 1961, we began growth of epitaxial films of GaAsP on GaAs substrates using a closed tube process, with iodine as the transport agent. In 1961 we also were routinely fabricating zinc diffused p-n junction devices, especially for the varactor diodes that were the large part, if not the whole part, of the devices which we used to study luminescence in GaAs in 1961 and in early 1962. In 1961, GT&E Labs had a substantial effort in progress to study gas lasers, and solid state crystalline and glass lasers. Some of the principals involved were Dr. Lou Bloom, Dr. Al Levine, and Dr. Alex Lempicki. It was problematic whether these efforts were going to be of great value to the corporation, and top levels of management that included Lee Davenport, the President of the Labs were not sympathetic to the prospect of pursuing yet another laser type program. In all likelihood, were it not for the interest in semiconductor lasers shown by several government groups late in 1961, GT&E Labs would have killed further work along this line. It is interesting that Dr. Paul Keck, the head of the Solid State Lab, and Dr. Mayburg's immediate superior, himself was engaged in developing a sun-powered crystalline or glass laser in competition with the other groups in the laboratories working on lasers. Thus it is not surprising that Dr. Keck was anxious to add more of his staff to the pursuit of laser technology, since it would give him more clout in this area. Once we began to think seriously of extracting useful radiation from LED's and of developing diodes that would “lase”, towards the end of the last quarter of 1961, things began to move very fast. I remember in particular several weekends, when a number of us in Sumners group worked overtime to make and test as many light emitting diodes as possible, gathering detailed data on spectral energy distribution, effects of current level, temperature, n-and p-doping level, etc. Towards the end of December, we had written a proposal for an “Electron Injection Laser", incorporating much of what we had learned over the previous few months. The period January 1962 through December 1963 saw intense investigations of injection electroluminescence at GT&E Labs, as well as at other laboratories such as GE, IBM, MIT, RCA, and BTL. We can produce plenty of documentation, especially from publications, for this period.
The Year 1962
On January 5, we submitted the proposal "Electron Injection Laser” to Fort Monmouth, NJ. It was likely that this same proposal was circulated to other interested government groups, because the award of a contract ultimately came from Fort Belvoir. In February, we submitted a post-deadline paper "High Efficiency Electroluminescence in GaAs” by J. F. Black, H. Lockwood and S. Mayburg, for the upcoming meeting of the American Physical Society in Baltimore, MD. This was done only after attempts to have our work published in Physical Review Letters were rebuffed, and the paper rejected on the basis that a paper on a similar subject, authored by J.L. Pankove and M. J. Massoulie of RCA Labs, was presented at the January Meeting of the American Physical Society, in New York City. In fact there were significant differences between these two papers, the most important of which was that in our GaAs diodes the ratio of band edge emission to impurity emission was far greater than in the diodes that were the subject of the other paper. This implied that our diodes were much more efficient. Entries in the notebooks of S. M. Ku and J. F. Black, U89; B10 (226); Y157-30 on pages 84; 44-45; 51; 30-31, described the invention of a visible light emitting diode made from GaAsP. At the invitation of Dr. Rolf Landauer, Sumner Mayburg gave a talk to scientists at IBM Laboratories, describing and discussing the work that had been going on in his group at GT&E Labs.
In March, Dr. Mayburg presented the post-deadline paper, described above, at the Baltimore Meeting of the American Physical Society (3/28/62). Another paper, “High Frequency Base-Transport Factor and Transit Time of Graded Base Transistors” by S. Mayburg and B. Smith was published in the IRE Transactions, Volume ED-9, and pp. 161-164.
On May 14, we achieved red light emission at room temperature from a forward biased p-n junction in GaAsP. The notebook reference was not given, but S. M. Ku and J. F. Black were both involved, and it was undoubtedly one of those same notebooks in which the invention of the visible light emitting diode, mentioned above, was described.
On June 30, we began work on the contract awarded to GT&E Labs by Fort Belvoir. The title of this contract was “Applied Infrared Laser Research.”
In July, we submitted a paper "Recombination Radiation in GaAs” by J. F. Black, H. Lockwood, and S. Mayburg, to the Journal of Applied Physics. This was essentially the post deadline paper presented at the Baltimore Meeting.
In September, we submitted a paper "Visible Injection Electroluminescence from GaAs-GaP Diodes" by H. F. Lockwood, S. M. Ku, and J. F. Black, far presentation at the November Meeting of The American Physical Society, in Cleveland.
In November, on the 21st, we achieved lasing in a GaAs diffused diode, with a mesa structure, at liquid nitrogen temperature. Entry in J. B1ack’s notebook B1, page 90. The paper "Visible Electroluminescence from GaAs-GaP", by H. F. Lockwood, S. M. Ku, and J. F. Black, was presented by S. M. Ku in Cleveland on the 23rd. The presentation was picked up by the Electronic News and the New York Herald Tribune amid considerable fanfare from the "front office" that included statements of the President of GT&E Labs, Dr. Lee Davenport, lauding this "research breakthrough.’
In December, we achieved lasing in a diode with a rectangular shape in which two of the opposed faces were polished to form a resonant cavity. A high resolution spectrograph, usually used for analytical emission spectroscopy, was employed to resolve individual modes with line width on the order of 0.1A.
One very important point that should be made here concerns the development of a means to generate and deliver fast rise time (0.3 microsecond) high current pulses up to 100 amps for a few microseconds) into loads (the diodes) of only a few ohms resistance. We had been trying, since the middle of the year, to find such pulse generators because we knew that population inversion would have to be reached quickly to avoid serious diode heating. It was not until Dr. M.Fishman, of GT&E Labs, had designed and built such a pulse generator that we were able to achieve lasing. Marty's contribution to our success should not be forgotten.
The Year 1963
In January our paper "Recombination Radiation in GaAs" by J. F. Black, H. Lockwood, and S. Mayburg, was published in the Journal of Applied Physics, Volume 34, pp. 178-180.The Interim Report on the contract "Applied Infrared Laser Research", by J. F. Black, K. Arnold, and S. Mayburg, was submitted to Fort Belvoir on the 20th. Another paper entitled "Threshold Currents for Line Narrowing in GaAs Junction Diodes” by S. Mayburg, was submitted to Journal of Applied Physics.
On February 8, the invention of the GaAs laser by S. Mayburg and J. Birman described in Sumner's notebook Y236, page 94 was written up in disclosure form by the patent department. In February, a paper entitled “Injection Electroluminescence in GaAs-GaP Diodes” by S. M. Ku and J. F. Black was submitted to Solid State Electronics. Another paper, written by S. M. lu, "The Preparation and Properties of Vapor-Grown GaAs-GaP Alloys,” was submitted to the Journal of The Electrochemical Society.
In March, the invention of a cylindrical GaAs laser diode was recorded in notebook B119, page 76 (probably K. Arnold’s notebook). A paper written by H. F. Lockwood, “Polarization in Junction Luminescence”, was submitted to the Journal of Applied Physics. Another paper, "Effect of n-Dopant on Stimulated Emission in GaAs Diodes” by J. F. Black and R. Harrigan was submitted for presentation at the Pittsburgh Meeting of the Electrochemical Society in April.
On April 17th, the above paper was presented by J. F. Black at the ECS Meeting, in Pittsburgh, PA.
In May, a paper "Cylindrical GaAs Laser Diode" by K. Arnold and S. Mayburg, was submitted to the Journal of Applied Physics.
In June, the paper "Threshold Currents for Line Narrowing in GaAs Junction Diodes" by S. Mayburg was published in Journal of Applied Physics, Volume 34, pp. 1791-1793. Two other papers were submitted, "Temperature Limitation on Continuous Operation of GaAs Lasers" by S. Mayburg to the Journal of Applied Physics, and “Antireflection Films on GaAs Electro-luminescent Diodes" by O. Weinreich to the Journal of the Electrochemical Society.
On July 12, a patent application was filed on the GaAs laser invented by S. Mayburg and J. Birman in December 1961. The patent was titled "Optical Maser". On the 20th, the final report on the Fort Belvoir contract ''Applied Infrared Laser Research” was submitted. The paper "Polarization in Junction Luminescence” by H. F. Lockwood, was published in the Journal of Applied Physics, Volume 34, pp. 2110-2111.
In September “The Preparation and Properties of Vapor-Grown GaAs-GaP Alloys" by S. M. Ku, was published in the Journal of the Electrochemical Society, Volume 110, pp. 991-995.
In October, "Cylindrical GaAs Laser Diode" by K. Arnold and S. Mayburg, was published in Journal of Applied Physics, Volume 34, pp. 3136.
In November, “Temperature Limitation on Continuous Operation of GaAs Lasers" by S. Mayburg was published in Journal of Applied Physics, Volume 34, pp. 3417-3418. Another paper was also published, "Antireflection Films on GaAs Electroluminescent Diodes" by D. Weinreich in the Journal of the Electrochemical Society, Volume 110, pp. 1124-1126.
The Year 1964
This year saw the GT&E Labs activity in LED's and laser diodes being considerably reduced, and the principal participants being encouraged to direct their efforts elsewhere.
In February, a paper entitled "Comparison of Monochromatic Semiconductor Radiation Sources with Tungsten Lamps" by 0. Weinreich and S. Mayburg, was submitted for publication in Applied Optics.
In March, two papers on AIGaAs were submitted for presentation at an upcoming meeting of the Electrochemical Society in Toronto, Canada. They were “Preparation and Properties of AlAs-GaAs Mixed Crystals" by J. F. Black and S. M. Ku, and "Injection Electroluminescence in AIAs-GaAs Diodes" by S. M. Ku and J. F. Black. Because we didn't want to tip our hand, we chose to make public disclosure of our work in this area through a recent news session. This stratagem assured us that we would be the first to publish, unless one of our competitors had a manuscript all ready to "go", since less than two months would elapse between submission and presentation.
In May, the two papers described above were presented at the Spring Meeting of the Electrochemical Society, in Toronto Canada. There was intense interest in these papers and much extended discussions, off of the floor, especially by Mort Panish and Forrest Trumbore of Bell Labs.
In July, the Journal of the Electrochemical Society recorded our presentations and the Abstracts, in the Current Affairs section of Volume 111, on page 155C. In September, Dr. Sumner Mayburg left GT&E Laboratories, and shortly thereafter his group was broken up.
In December, the paper “Comparison of Monochromatic Semiconductor Radiation Sources with Tungsten Lamps” by Otto Weinreich and Sumner Mayburg, was published in Applied Optics, Volume 3, pp. 1489-1493. No further publications in the field of light emitting materials or devices were forthcoming, except the publication of the full papers on AlGaAs materials and devices, cited above, which did not occur until 1966.