Photoluminescence and energy-loss rates in GaAs quantum wells under high-density excitation

The time-resolved luminescence spectra from excited conduction subbands in three samples of multi-quantum-well GaAs/AlxGa1−xAs (x=0.3 and 1) semiconductors with several well widths and barrier heights were obtained under high-density excitations by a 30-ps pulsed laser at 532 nm, which generated electron–hole pairs to the concentration of 1010–1013/cm2 per well per pulse at 77 K. The temperature and the Fermi energy of electron were determined by fitting best the constructed time-resolved spectrum to the observed, and the time-dependent electron energy was obtained by using these parameters. The energy-loss rates of hot electrons are at least twice smaller than the calculated ones induced by the electron-polar phonon scattering, including the screening effect due to the high carrier density.