106 research outputs found
Shock Waves in Nanomechanical Resonators
The dream of every surfer is an extremely steep wave propagating at the
highest speed possible. The best waves for this would be shock waves, but are
very hard to surf. In the nanoscopic world the same is true: the surfers in
this case are electrons riding through nanomechanical devices on acoustic waves
[1]. Naturally, this has a broad range of applications in sensor technology and
for communication electronics for which the combination of an electronic and a
mechanical degree of freedom is essential. But this is also of interest for
fundamental aspects of nano-electromechanical systems (NEMS), when it comes to
quantum limited displacement detection [2] and the control of phonon number
states [3]. Here, we study the formation of shock waves in a NEMS resonator
with an embedded two-dimensional electron gas using surface acoustic waves. The
mechanical displacement of the nano-resonator is read out via the induced
acoustoelectric current. Applying acoustical standing waves we are able to
determine the anomalous acoustocurrent. This current is only found in the
regime of shock wave formation. We ontain very good agreement with model
calculations.Comment: 14 Pages including 4 figure
Nanopillar Arrays on Semiconductor Membranes as Electron Emission Amplifiers
A new transmission-type electron multiplier was fabricated from
silicon-on-insulator (SOI) material by integrating an array of one dimensional
(1D) silicon nanopillars onto a two dimensional (2D) silicon membrane. Primary
electrons are injected into the nanopillar-membrane system from the flat
surface of the membrane, while electron emission from the other side is probed
by an anode. The secondary electron yield (SEY) from nanopillars is found to be
about 1.8 times that of plane silicon membrane. This gain in electron number is
slightly enhanced by the electric field applied from the anode. Further
optimization of the dimensions of nanopillars and membrane and application of
field emission promise an even higher gain for detector applications and allow
for probing of electronic/mechanical excitations in nanopillar-membrane system
excited by incident particles or radiation.Comment: 4 figure
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