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, a consequence of non-local neutrality, which tends to open the gap and the many-body effects (mainly exchange ). Preliminary analysis for a lot of samples with widely different per iods provides a satisfactory fit with the Hartree-Fock model. The kine tics of luminescence and total decay in the electron hole plasma regim e is measured. In some samples, a phase transition is observed which i s tentatively interpreted in terms of the electron hole liquid condens ation.