Electron spin-polarization in p-doped quantum wells

We study both theoretically and experimentally the luminescence in non-intentionally but heavily p-doped GaAs quantum wells of 55 and 150A width. At T=2K the PL spectra under cw excitation present an excitonic peak and a broad acceptor band. Time-resolved optical pumping of the acceptor line allows us to measure the free electron spin relaxation time. We have investigated its temperature dependence in the 4-40K range. The experimental findings are interpreted in the framework of the D'Yakonov-Perel' mechanism for the electron gas