TIME-RESOLVED PHOTOLUMINESCENCE STUDY OF ORDERED GA0.5IN0.5P UNDER HIGH-PRESSURE

We have measured time-resolved photoluminescence (TR-PL) spectra in or dered and disordered Ga0.5In0.5P alloys at 12 K and at pressures up to 3 GPa to investigate the characteristics of the main broad PL spectru m at approximate to 1.91 eV in nominally ordered alloys. At normal pre ssure, unlike the disordered alloy, the PL-decay profiles far the orde red alloys change remarkably for small changes in detection energy. Th is indicates the presence of adjacent overlapping emissions of differe nt nature. Together with the prolonged nonexponential decay curves, a gradual red-shift of the low-energy peak with delay time is observed f or the first time, indicating spatially indirect recombinations. With increasing pressure, the constituent emissions shift toward higher ene rgies at rates slightly smaller than that for the disordered alloy. At 3 GPa, the PL decay appears to be insensitive to the detection energy , and a faster decay is observed.