Low-frequency noise in gallium nitride nanowire mechanical resonators
Abstract
We report on the low-frequency 1/f (flicker) parameter noise displayed by the resonance frequency of doubly clamped c-axis gallium nitride nanowire (NW) mechanical resonators. The resonators are electrostatically driven and their mechanical response is electronically detected via NW piezoresistance. With an applied dc voltage bias, a NW driven near its mechanical resonance generates a dc and Lorentzian rf current that both display 1/f noise. The rf current noise is proportional to the square of the derivative of the Lorentzian lineshape with a magnitude highly dependent on NW dc bias voltage conditions, consistent with a model wherein noise in the NW's electrical impedance leads to temperature noise from local Joule heating, which in turn generates resonance frequency noise via thermal expansion and the temperature-dependent Young's modulus. An example device with a 27.8 MHz resonance frequency experiences an approximate resonance frequency shift of −1.4 Hz/nW. The resonance frequency noise increases as the square of the bias voltage, indicating specific operating conditions that optimize the signal-to-noise ratio in proposed NW sensors.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 03, 2012
- Source ID
- 10.1063/1.4769445
Entities
People
- Charles T. Rogers
- Jason M. Gray
- Kris A. Bertness
- Norman A. Sanford
Organizations
- Defense Advanced Research Projects Agency
- National Institute of Standards and Technology
- University of Colorado