Effects of growth rate on lateral compositional modulation ofInGaAsP/InP(001) grown by metalorganic molecular beam epitaxy

摘要

Two sets ofIn_1-xGa_xAs_0.85P_0.15(0.35⩽x⩽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 0.25and 0.46 nm/s, respectively. Lattice mismatches of the InGaAsP layersrange from -0.5% (tension) to +0.3% (compression). Double crystal x-raydiffraction (DCXRD) is mainly used to characterize structural propertiesof lateral composition modulation (LCM). Asymmetric (224) rocking scansshow that the wavelength of the LCM is approximately 100 nm and that theamplitude of the LCM for 0.46 nm/s samples is smaller than that for 0.25nm/s ones over the entire composition range. Cross-sectionaltransmission electron microscopy (TEM) and photoluminescence (PL)measurements are also performed for the same samples. Theseinvestigations reveal that increasing the growth rate reduces the LCM