Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8130580 | Ultrasonics | 2015 | 6 Pages |
Abstract
Femtosecond laser pulses are used to excite and probe high-order longitudinal thickness resonances at a frequency of â¼270 GHz in suspended Si membranes with thickness ranging from 0.4 to 15 μm. The measured acoustic lifetime scales linearly with the membrane thickness and is shown to be controlled by the surface specularity which correlates with roughness characterized by atomic force microscopy. Observed Q-factor values up to 2400 at room temperature result from the existence of a local maximum of the material Q in the sub-THz range. However, surface specularity would need to be improved over measured values of â¼0.5 in order to achieve high Q values in nanoscale devices. The results support the validity of the diffuse boundary scattering model in analyzing thermal transport in thin Si membranes.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Acoustics and Ultrasonics
Authors
A.A. Maznev, F. Hofmann, J. Cuffe, J.K. Eliason, K.A. Nelson,