Room temperature piezoelectric displacement detection via a silicon field effect transistor

An electromechanical oscillator embedded with a two dimensional electron gas is capacitively coupled to a silicon field effect transistor (Si-FET). The piezovoltage induced by the mechanical motion modulates the current passing through the Si-FET enabling the electromechanical oscillator's position to be monitored. When the Si-FET is biased at its optimal point, the motion induced piezovoltage can be amplified resulting in a displacement sensitivity of 6 x 10(-12) mHz(-1/2) for a 131 kHz GaAs resonator which is among the highest recorded for an all-electrical room temperature detection scheme. (C) 2009 American Institute of Physics. [doi:10.1063/1.3271525]