Phonon-plasmon coupled-mode lifetime in semiconductors

Raman scattering measurements of the lifetime of hot phonons in GaN show a decrease with increasing electron concentration. Density-dependent lifetimes have also been deduced from noise measurements of AlGaN/GaN channels. We suggest that the results from Raman scattering can be understood by the frequency dependence of the anharmonic interaction for coupled modes and that the results from noise measurements can be understood qualitatively by the anharmonic interaction plus the migration of coupled modes. (C) 2008 American Institute of Physics.