Effects of growth rate on lateral compositional modulation of InGaAsP/InP[001] grown by metalorganic

Abstract

Two sets of In/sub 1-x/Ga/sub x/As/sub 0.85/P/sub 0.15/(0.35/spl les/x/spl les/0.45) epitaxial layers have been grown on InP [001] substrates with a composition lying within a miscibility gap, using metalorganic molecular beam epitaxy (MOMBE) at growth rate of 0.25 and 0.46 nm/s, respectively. Lattice mismatches of the InGaAsP layers range from -0.5% (tension) to +0.3% (compression). Double crystal x-ray diffraction (DCXRD) is mainly used to characterize structural properties of lateral composition modulation (LCM). Asymmetric [224] rocking scans show that the wavelength of the LCM is approximately 100 nm and that the amplitude of the LCM for 0.46 nm/s samples is smaller than that for 0.25 nm/s ones over the entire composition range. Cross-sectional transmission electron microscopy (TEM) and photoluminescence (PL) measurements are also performed for the same samples. These investigations reveal that increasing the growth rate reduces the LCM.