TEMPERATURE AND EXCITATION INTENSITY DEPENDENCIES OF THE PHOTOLUMINESCENCE SPECTRA OF GAAS (ALGA)AS DISORDERED SUPERLATTICES/

The temperature and excitation intensity dependencies of the photolumi nescence (PL) spectra of GaAs/Al0.3Ga0.7As superlattices (SL's) having randomly distributed well widths are studied. Our results indicate th at the electronic properties of disordered SL's are similar to those o f other disordered semiconductors: at low energies the electronic stat es are essentially localized, while at higher energies they are extend ed. Further, the PL spectra feature a disorder-induced fine structure, and they shift to the red with T simply following the reduction of th e band gap. The PL efficiency shows a weaker decrease with increasing T than the ordered SL. The dependence of the PL spectra on the excitat ion intensity shows an anomalous behavior of the disorder-induced fine -structure recombination lines.