ELECTRON INTERSUBBAND RELAXATION IN DOPED QUANTUM-WELLS

The intersubband relaxation time of an electron is calculated by consi dering electron-electron and electron-phonon (bulk LO phonon) scatteri ng in a GaAs quantum well. The relaxation time is derived and numerica lly evaluated within the random-phase approximation with full multiple subband and frequency-dependent screening. The electron scattering du e to the coupled system of electrons and phonons is compared with the decoupled scattering where both electron-electron and unscreened elect ron-phonon scattering are considered separately. It is shown that the intersubband relaxation time is heavily influenced by the electron den sity in the well. It is also shown that at room temperature it is nece ssary to use the finite-temperature dielectric function to accurately determine the intersubband relaxation time.