▎ 摘　　要

We demonstrate the detection of mechanical oscillations of a nanoelectromechanical system (NEMS) composed of a multilayer-graphene (MLG) membrane by using a Si field-effect transistor (FET). The MLG membrane of 500 nm in length is suspended above multiple nanowire channels of the FET functioning as a sensor with high sensitivity. A microwave probe in contact with the FET is connected to double-resonant circuits composed of two inductors and capacitors, and a radio-frequency (rf) signal drives the FET in the resonant condition. When the MLG membrane functioning as a gate of the FET oscillates in mechanical resonance and modulates impedance of the FET, this modulation is monitored using a reflected signal from the resonant circuits. By adjusting the resonant condition using a variable capacitor, the mechanical oscillations of the MLG membrane are detected at 340 MHz. Such rf-signal-driven readout of the NEMS operating at subgigahertz frequency will lead to highly sensitive and functional sensors for small mass and quantum mechanics as well as timing devices.