Propagation of THz acoustic wave packets in GaN at room temperature
Name
Propagation_of_THz_acoustic_wave_packets_in_GaN_at.pdf
Description
Published version
Size
1.14 MB
Format
Adobe PDF
Checksum (MD5)
790a7100040ceaf3a8f8a9311440904f
Author(s)
Maznev, Alexei
Hung, T.-C.
Yao, Y.-T.
Chou, T.-H.
Gandhi, J. S.
Lindsay, L.
Shin, H. D.
Stokes, D. W.
Forrest, R. L.
Bensaoula, A.
Date Issued
February 6, 2018
Journal
Applied Physics Letters
Publisher
AIP Publishing LLC
Citation
Maznev, Alexei et al. "Propagation of THz acoustic wave packets in GaN at room temperature." Applied Physics Letters, 112, 6, (February 2018): 061903 © 2018 Authors
Version
Final published version
Abstract
We use femtosecond laser pulses to generate coherent longitudinal acoustic phonons at frequencies of 1-1.4 THz and study their propagation in GaN-based structures at room temperature. Two InGaN-GaN multiple-quantum-well (MQW) structures separated by a 2.3 μm-thick GaN spacer are used to simultaneously generate phonon wave packets with a central frequency determined by the period of the MQW and detect them after passing through the spacer. The measurements provide lower bounds for phonon lifetimes in GaN, which are still significantly lower than those from first principles predictions. The material Q-factor at 1 THz is found to be at least as high as 900. The measurements also demonstrate a partial specular reflection from the free surface of GaN at 1.4 THz. This work shows the potential of laser-based methods for THz range phonon spectroscopy and the promise for extending the viable frequency range of GaN-based acousto-electronic devices.
Subjects
Physics and Astronomy (miscellaneous)
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/1.5008852
