Carbon nanotube resonators with capacitive and piezoresistive current modulation readout

Abstract

In this work, a single-walled carbon nanotube (SWCNT) nanomechanical resonator is characterized at mechanical resonance using both capacitive modulation and piezoresistive modulation effects. The piezoresistive modulation effect is shown to be a robust method for measuring the resonant response, allowing improved detection of the SWCNT resonance by reducing the off-resonance drain current by a factor of up to 10. Equivalent circuit parameters describing the piezoelectric effect are extracted. The measured device shows a Q-factor of 91 and a piezoresistive bandgap bending of 0.04 eV/% strain for a resonance at 79.5 MHz. The SWCNT is measured at 300 K and 7 × 10−4 Pa.