MICROSTRUCTURE AND CATHODOLUMINESCENCE OF MBE-GROWN (001) INXGA1-XP/GAAS STRAINED-LAYER HETEROSTRUCTURES

InxGa1-xP(x = 0.436-0.546)/GaAs heterostructures grown on (001) GaAs substrates by molecular beam epitaxy have been studied using transmission electron microscopy (TEM) and cathodoluminescence (CL) techniqUeS. TEM study of plan-view and cross-sectional samples of the epitaxial layers revealed no evidence of CuPt-type atomic ordering in the InGaP layers, but two types of composition modulation in the InGaP layers were observed. Different strain relaxation mechanisms for the layers in tension and compression were also observed. CL analysis was carried out for both strained and relaxed InGaP layers The dependence of CL emission energy and of peak width on the misfit strain is discussed and correlated with the TEM study. Biaxial compressive strain increases the CL emission energy and reduces the emission peak width. Biaxial tensile strain relaxation near to the microcracks was also studied by CL.