and Computer Engineering Associate Professor Robert
Blick and colleagues in Germany have demonstrated a
new nanoscale mechanism for field emission that could
lead to a new type of energy efficient flat-panel display.
The team's article in Physical Review Letters describes
how a nanoscale gold-tipped island is able to mechanically
oscillate between two facing electrodes, which provide
recharging and detection of the emission current. Additionally,
unlike many nanoscale experiments in field emission,
the device does not need to be cryogenically cooled.
emission, also called Fowler-Nordheim tunneling, is
the process in which electrons tunnel through a barrier
in the presence of a high electric field. This quantum
mechanical tunneling process is an important mechanism
for thin barriers such as those in metal-semiconductor
junctions on highly-doped semiconductors. With its
nanoscale device, the team is able to trace and reproduce
the transition from current flow through a rectangular
tunneling barrier to the regime of field emission.
emission from microscopic tips has been a fundamental
tools of experimental physics for decades, and nanoscale
emitters are the subject of intense research"
explains Robert Blick. "However, contrary to
earlier observed deviation from the Fowler-Nordheim,
our isolated nanomechanical pendulum shows new behavior
already at low voltages. The fact that the emitter
is isolated alters the Fowler-Nordheim description
to a behavior which becomes linear for large voltages."
team will continue its research with the goal of understanding
how field emission is performed in a controlled fashion,
one electron at a time.