Photoluminescence studies of type-II self-assembled InAlAs/AlGaAs QDs grown on (311)A GaAs substrate

The photoluminescence (PL) spectra of self-assembled In0.55Al0.45As/Al0.45G a0.5As quantum dots (QD) grown on (311)A GaAs substrate were measured. The type- I character of PL related to the X valley was verified by excitation power dependence of peak position and the PL spectra under different pressu re , which was attributed to the type- II transition from X valley in Al0.5 Ga0.5As to heavy holes in In0.55Al0.45As The high energy Gamma -related tra nsition was also observed above 70K and assigned as the transition between Gamma valley and heavy holes in In-0.55 Al0.45As. The X-valley split was di scussed to interpret the observed second X-related peak under pressure.