Time-resolved Raman scattering of nonequilibrium LO phonons in GaAs quantum wells

Abstract

Time-resolved resonant Raman spectroscopy has been used to study the properties of nonequilibrium GaAs LO phonons generated as a result of the cascade of photoexcited carriers in GaAs quantum wells. The average population relaxation time of these LO phonons, which are responsible for hot-phonon effects in GaAs quantum wells, is directly measured to be 8\ifmmode\pm\else\textpm\fi{}1 ps at $T\ensuremath{\simeq}10$ K. These experimental results should help determine quantitatively and accurately the role hot phonons play in the hot-carrier dynamics of multiple-quantum-well structures.