Using an ensemble Monte Carlo simulation, we investigate intersubband relaxation of photoexcited electrons in GaAs/AlGaAs quantum wells having a subband separation smaller than the polar optical phonon energy. In this paper, we report on simulation of modulation-doped structures similar to experimental samples recently studied with intersubband pump and probe spectroscopy using a free-electron laser. For modulation-doped samples, intersubband relaxation due to intercarrier scattering is an important effect at short times, whereas at longer times polar optical and acoustic phonons dominate the intersubband decay. For low excitation density conditions, interface scattering is found to contribute greatly to the intersubband decay of the carriers during the initial pulse for even moderate interface charge densities.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry