It is well known that nonequilibrium populations of phonons can be generated in bulk semiconductors by the relaxation of photoexcited hot electrons. In this paper we demonstrate that nonequilibrium phonons can also be generated in quantum wells by picosecond lasers and then probed by time-resolved Raman scattering. Using this method we have studied the interaction between hot electrons and interface and confined LO phonons in GaAs/AlAs quantum wells for well widths varying between 2 to 6 nm. The results are compared quantitatively with three macroscopic models of electron-LO phonon interaction. Only the model proposed by Huang and Zhu agrees both qualitatively and quantitatively with experimental results.
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Electrical and Electronic Engineering