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

Two sets of In_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 0.25 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