Influence of nitrogen on coherent longitudinal optical phonons in GaAs1− <i>x</i> N <i>x</i>
Abstract
We investigated the influence of nitrogen (N) on coherent longitudinal optical (LO) phonons in dilute nitride semiconductor alloys. Terahertz time-domain spectroscopy reveals a reduced frequency (redshift) of LO phonons and enhanced decay times for coherent GaAs-like LO phonons emitted from GaAs1−xNx in comparison to those from semi-insulating GaAs. We attribute the redshift of the phonon frequency to both N-alloying-induced compression of the As-sublattice and tensile coherency strain at the GaAs1−xNx/GaAs interface. In addition, an N-induced enhancement of the coherent phonon decay time is attributed to reduced LO phonon scattering associated with the enhanced electron effective masses that reduce the transient electron velocity.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (6)
Hideo Takeuchi
Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University (formerly Osaka City University) 1 , 1-1 Gakuen, Naka, Sakai, Osaka 599-8531,
Kai Matsunaga
Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University (formerly Osaka City University) 1 , 1-1 Gakuen, Naka, Sakai, Osaka 599-8531,
Yusuke Sengi
Department of Applied Physics, Graduate School of Engineering, Osaka City University (currently Osaka Metropolitan University) 2 , 3-3-138, Sugimoto, Sumiyoshi, Osaka 558-8585,
Jared W. Mitchell
Department of Physics, University of Michigan 2 , Ann Arbor, Michigan 48109,
Yury Turkulets
Rachel S. Goldman
Department of Materials Science and Engineering, University of Michigan 1 , Ann Arbor, Michigan 48109,