Hot-electron relaxation via the emission of GaAs optical modes and AlAs interface modes in GaAs/AlAs multi-quantum wells

Abstract
We demonstrate via hot-electron photoluminescence and high-temperature mobility measurements the importance of the AlAs interface mode in the energy relaxation of electrons in GaAs/AlAs multi-quantum wells. A corresponding investigation of a similar GaAs/Al0.24Ga0.76As system illustrates that this is not the case for AlGaAs barrier devices where GaAs modes are the dominant energy relaxation process. The importance of the AlAs interface mode is not simply related to its intrinsic scattering rate but also to its shorter lifetime (compared with GaAs modes). Hot-phonon effects are therefore crucial to a full understanding of the experimental data.