SELF-SENSING TORSIONAL RESONATORS BASED ON INORGANIC NANOTUBES

Carbon and inorganic nanotubes have unique mechanical and electronic properties, which make them attractive components for nanoelectromechanical systems (NEMS). Many of these properties have been extensively researched in carbon nanotubes. However, the electromechanical behavior of inorganic nanotubes at torsional resonance has yet to be studied. We here in present a study of electromechanical torsional resonators based on multi-wall WS₂ nanotubes. The resonance spectrum of devices is measured using electrical current mixing, where detection is based on the piezoresistivity of WS₂ nanotubes. The resonance spectrum is also detected optically using a laser Doppler vibrometer, correlating the electrical and mechanical response of the devices. Devices are characterized under high vacuum as well as ambient conditions, revealing the extrinsic and intrinsic sources of energy loss in the torsional devices. The WS₂ nanotube torsional resonators are robust and characterized by high resonant frequencies, and are readily detected electrically, allowing for self-sensing NEMS devices which could be employed in various sensors, such as gyroscopes and accelerometers.