Hot-electron energy relaxation rates in GaAs/GaAlAs quantum wells

Experimental results of high-field parallel transport in GaAs/GaAlAs multiple quantum wells are presented. The experiments make use of steady-state photoluminescence spectroscopy and Hall effect measurements in the hot-electron regime. In a nominally undoped sample with n=1.55*10 10 cm -2 per well, the effective energy relaxation time is constant and tau eff =127 fs. In a modulation-doped degenerate sample with n=1.38*10 12 cm -2 per well, however, tau eff is found to be an order of magnitude longer and to vary somewhat with the electron temperature. The results are compared with a simple analytical model based on the production of hot phonons.