Optical Phonon Coherence and Population Decays in III–V Semiconductors

Abstract

Investigations of optical phonon coherence and population decays in bulk III–V semiconductors are discussed. The results are compared to our lifetime determinations using a non phonon-mode selective technique based on precise measurement of electron-lattice thermalization dynamics. The measured LO phonon lifetimes were found to be consistent with the dephasing times measured in intrinsic samples. In the presence of carriers (for the density range 1016–1017 cm -3), due to LO phonon-plasmon hybridization, the dephasing time is strongly reduced and becomes much smaller than the lifetime which is almost not altered. The roles of pure dephasing and population decay mechanisms in optical phonon relaxation are discussed for various carrier environment.