Growth of GaInP/GaAsP Short Period Superlattices by Flow Modulation Organometallic Vapor Phase Epitaxy

摘要

One disadvantage of the GaInP/GaAs system is the difficulty often encountered in synthesizing the quaternary material GaInAsP, required to span the intermediate bandgap range (1.42-1.91 eV). Recent studies report on an extensive miscibility gap in this alloy. In this study, we investigate an alternative approach to the growth of material within this bandgap range. We have grown by flow-modulation organometallic vapor phase epitaxy, GaInP/GaAsP superlattices with periods ranging from 80 to 21A. These are the first reported short-period superlattices in this material system. Effects of superlattice (SL) period, growth temperature, and phosphorous composition in the wells were studied by photoluminescence, high resolution x-ray diffraction, atomic force microscopy, and transmission electron microscopy. The effect of growth temperature on the structural quality of the SLs is correlated to ordering effects in the GaInP layers. Variations in the P composition and the SL period result in a shift in the room temperature bandgap emission from 1.51 to 1.74 eV. Strain-compensated structures have been realized by growing the SL barriers in compression.