Effects of interface roughness and phonon scattering on intersubband absorption linewidth in a GaAs quantum well

We experimentally and theoretically study the effects of interface roughness and phonon scattering on intersubband absorption linewidth in a modulation-doped GaAs/AlAs quantum well. Quantitative comparisons between experimental results and theoretical calculations make it clear that interface roughness scattering is the dominant scattering mechanism for absorption linewidth in the temperature range below 300 K. Even at room temperature, phonon scattering processes contribute little to linewidth, while polar-optical phonon scattering limits electron mobility. (C) 2001 American Institute of Physics.