Intra- and Intersubband Transition Rates Due to Emission of Optic Phonons in Quantum Wells: Effects of The Subband Nonparabolicity

Abstract

Electron-phonon interaction in polar semiconductor quantum wells attracted a great amount of interest over the last years due to its importance for electronic properties. Particular interest was directed towards LO-phonon confinement which affects significantly the scattering rates in quantum wells. In general, the use of dielectric continuum models is considered as well established¹ and scattering rates calculated with such models compare successfully with experimental results.² From the calculation of capture times³ it became evident that capture processes with large kinetic energy influence the overall capture time. For those large kinetic energies, implying in large momenta, the parabolic-band approximation becomes less justified even for GaAs-AlGaAs structures where in general nonparabolicity effects can be safely neglected. A question which has not yet been properly addressed is how strongly the subband nonparabolicity affects the intra- and intersubband scattering rates in quantum wells.