Electron–electron inter-subband scattering in GaAs quantum wells
The role of electron–electron scattering in the dynamics of inter-subband relaxation in GaAs quantum wells is investigated theoretically. The scattering rate is calculated using the Fermi golden rule, as a function of the carrier densities. The dependence of the inter-subband relaxation time on the quantum-well width is also investigated. Calculations are performed for multiple quantum-well structures with well widths varying from 80 to 240 Å (1 Å = 10−10 m). The hot electron distribution and the subband occupation function are taken into account in these calculations. Results show that the electron–electron scattering rate increases linearly as a function of the carrier densities. A band-filling effect limits the efficiency of this mechanism under high carrier densities (> 1012 cm−2). For thick well (180 Å) structures, this relaxation channel is as efficient as the phonon relaxation channel.