Temperature-dependent mechanical-resonance frequencies and damping in ensembles of gallium nitride nanowires

Published: October 22, 2012


Kristine A. Bertness, Norman A. Sanford, J. R. Montague, H.S. Park, Victor M. Bright, Charles T. Rogers


We have measured singly clamped cantilever mechanical-resonances in ensembles of as-grown gallium nitridenanowires (GaN NWs), from 12 K to 320 K. Resonance frequencies are approximately linearly dependent on temperature near 300 K with relative shifts of 40 {plus or minus} 20 ppm/K, consistent with temperature-dependent elastic moduli. Below 100 K, we find that some GaN NWs have mechanical quality factors well above 400 000, at mechanical resonance frequencies near 1 MHz. We also observe a correlation between increased amplitude of dissipation and increased temperature dependence of resonance frequencies. The microwavehomodyne detection technique we use is simple, allows for the investigation of as-grown or processed NWs, and is sensitive enough to observe the thermal motion of individual NWs while providing for the simultaneous measurement of large ensembles of NW mechanical resonances.
Citation: Applied Physics Letters
Volume: 101
Issue: 17
Pub Type: Journals
Created October 22, 2012, Updated November 10, 2018