Optimizing features of LT-GaAs/AlGaAs Stark geometry photorefractive devices

Low temperature grown (LT) GaAs/AlGaAs Stark geometry photorefractive devices were studied due to their wide application in optical information processing. Sharp exciton absorption in LT-grown GaAs/AlGaAs MQWs region and effective trap centers in LT-grown AlGaAs trap layers are both important for Stark geometry photorefractive device to achieve large photorefractive effect. Two groups of samples were grown at 350/spl deg/C by MBE. Multiple quantum wells (MQWs) of 4nm GaAs/7.5nm Al/sub 0.3/Ga/sub 0.7/As, as the first group, were grown at As pressure from 1.5 /spl times/ 10/sup -7/ to 3.2 /spl times/ 10/sup -7/ Torr. With the optimized MQW region and different trap layers, Stark geometry photorefractive devices were obtained as the second group samples. The structure and the device process were described as before. During the growth of trap layers, As pressure was changed from 3.8 /spl times/ 10/sup -7/ to 9.8 /spl times/ 10/sup -7/ Torr.