Number 618 #1, December 23, 2002 by Phil Schewe, James Riordon, and Ben Stein
Tuning Carbon Nanotube Resonance Frequencies
Tuning carbon nanotube resonance frequencies can be achieved by varying
a static voltage applied between the nanotubes and a counter electrode.
This was demonstrated for several nanotubes (NT) grown on a nickel support
tip. The natural resonant NT frequencies are those where the NT oscillates
with a large amplitude, a motion that can be monitored directly by watching
the pattern of electrons spraying out the end of the tubes (like water
spraying out of a wiggling garden hose). The vibration is excited by
applying an additional sinusoidal voltage of the correct frequency to
one of the electrodes (see figure).
This technique gives researchers yet another handle for manipulating
the versatile NT's for what promises to be wide variety of applications.
According to Stephen Purcell of the University of Lyon (email@example.com),
one of the co-authors on a new paper reporting the results, carefully
excited and tuned NT's may act as the core for future nanometric oscillator
circuitry, nano-balances or nano-force sensors. (Purcell
et al., Physical Review Letters, 30 December 2002;
for a past summary of NT thermal, electrical, and optical emissions,