Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN

K. T. Tsen, R. P. Joshi, D. K. Ferry, A. Botchkarev, B. Sverdlov, A. Salvador, H. Morkoc

Research output: Contribution to journalConference article

Abstract

Non-equilibrium electron distributions as well as phonon dynamics in wurtzite GaN have been measured by subpicosecond time-resolved Raman spectroscopy. Our experimental results have demonstrated that for electron densities n ≥ 5 × l017cm-3, the non-equilibrium electron distributions in wurtzite GaN can be very well described by Fermi-Dirac distribution functions with the temperature of electrons substantially higher than that of the lattice. The population relaxation time of longitudinal optical phonons was directly measured to be τ = 5 ± 1 ps at T = 25 K. The experimental results on the temperature dependence of the lifetime of longitudinal optical phonons suggest that the primary decay channels for these phonons are the decay into (1) one transverse optical phonon and one high energy, longitudinal or transverse acoustical phonons; and (2) one transverse optical phonon and one E2 phonon.

Original languageEnglish
Pages (from-to)737-742
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume449
StatePublished - 1997
EventProceedings of the 1996 MRS Fall Symposium - Boston, MA, USA
Duration: Dec 2 1996Dec 6 1996

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