GROWTH OF GAINP GAASP SHORT-PERIOD SUPERLATTICES BY FLOW MODULATION ORGANOMETALLIC VAPOR-PHASE EPITAXY/

One disadvantage of the GaInP/GaAs system is the difficulty often enco untered in synthesizing the quaternary material GaInAsP, required to s pan the intermediate bandgap range (1.42-1.91 eV). Recent studies repo rt on an extensive miscibility gap in this alloy. In this study, we in vestigate an alternative approach to the growth of material within thi s bandgap range. We have grown by flow-modulation organometallic vapor phase epitaxy, GaInP/GaAsP superlattices with periods ranging from 80 to 21 Angstrom. These are the first reported short-period superlattic es in this material system. Effects of superlattice (SL) period, growt h temperature, and phosphorous composition in the wells were studied b y photoluminescence, high resolution x-ray diffraction, atomic force m icroscopy, and transmission electron microscopy. The effect of growth temperature on the structural quality of the SLs is correlated to orde ring effects in the GaInP layers. Variations in the P composition and the SL period result in a shift in the room temperature bandgap emissi on from 1.51 to 1.74 eV. Strain-compensated structures have been reali zed by growing the SL barriers in compression.