TEMPERATURE-DEPENDENCE OF PHOTOLUMINESCENCE PROPERTIES OF GaAs/AlAs SUPERLATTICES GROWN ON DIFFERENT GaAs ORIENTATIONS

Optical characterization of (GaAs) 5 /(AlAs) 5 superlattices grown on (111)A, (311)A and (001) oriented semi-insulating substrate of GaAs is reported in this work. The samples were grown by the MBE technique. An investigation of the photoluminescence spectra as a function of the temperature reveals an increase of thermal activation energy in sample grown on (311)A plane when compared with the others, evidencing an additional lateral confinement. The results suggest that the superlattice grown on (111)A has a better interface. The energy peak dependence on temperature shows a bimodal behavior, having a certain behavior up to a critical temperature and, starting from this temperature, seems to follow the dependence of the AlAs energy gap. Pseudodirect transitions were observed for all directions.