Saturation of intersubband transitions in p-doped GaAs∕AlGaAs quantum wells

Abstract

Optical saturation experiments have been performed on hh1-hh2 intersubband transitions in two samples of p-doped GaAs∕AlGaAs quantum wells. The transitions had energies of 183 and 160meV and the measured population relaxation times were 2±1.5 and 0.3±0.1ps, respectively. Modeling of the quantum wells with a 6×6 k⋅p method shows that intersubband scattering by LO phonons can account for these relaxation times. The valence bandstructure is typically more complicated than the conduction bandstructure in a quantum well but these measurements show that LO phonons are the dominant intersubband scattering mechanism in both cases.