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Low-frequency noise in gallium nitride nanowire mechanical resonators



Jason Gray, Kristine A. Bertness, Norman Sanford, Charles T. Rogers


We report on the low-frequency 1/f (flicker) parameter noise displayed by the resonance frequency and resistance 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 Lorentzian current signal which, when lock-in detected, displays a modulated, drive-frequency-dependent 1/f noise component. This 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 noise in the NW's resistance leading to temperature, and hence resonance frequency noise due to local Joule heating. An example device with a 27.8 MHz resonance frequency and 220 kΩ} resistance experiences an approximate resonance frequency shift of -5.8 Hz/nW. In terms of NW resistance change, this corresponds with shifts of 0.1 Hz/Ω} and 2.6 Hz/Ω} at 1 V bias and 4 V bias, respectively, with an average resistance fluctuation of 1 kΩ} in a 1-second bandwidth.
Applied Physics Letters


gallium nitride nanowires, nanomechanical resonators, 1/f noise


Gray, J. , Bertness, K. , Sanford, N. and Rogers, C. (2012), Low-frequency noise in gallium nitride nanowire mechanical resonators, Applied Physics Letters, [online], (Accessed April 14, 2024)
Created December 6, 2012, Updated October 12, 2021