TYPE-II GAAS ALAS SUPERLATTICES UNDER HIGH-EXCITATION/

High intensity photoluminescence data on GaAs/AlAs superlattices and m ulti quantum wells of type II at low temperature are reported. The var iation with density of the renormalized band gap reveals the competiti on between the Hartree energy and the many-body effects (mainly exchan ge). Preliminary analysis for a lot of samples with widely different p eriods provides a satisfactory fit with Hartree-Fock model. The kineti cs of luminescence and total decay in the electron-hole plasma regime is measured. In some samples, a phase transition was observed which is tentatively interpreted in term of electron-hole liquid condensation.