Resonant generation of nonequilibrium phonons in GaAs/AlAs quantum wells via intersubband scattering

摘要

The authors have studied the resonant intersubband scattering of optical phonons or RISOP theoretically and by picosecond scattering. Experimentally, the authors have established a way to determine phonon occupancy in quantum wells. The model calculation shows that a significant amount of long wavelength LO phonons are generated by RISOP in GaAs/AlAs quantum wells. However, they measured a much smaller phonon population than predicted. The discrepancy can be explained by a breakdown of in-plane wavevector conservation due to interface roughness.