Optimization of growth temperatures for InAlAs metamorphic buffers and high indium InGaAs on InP substrate

Abstract

In0.83Ga0.17As layers were grown on InP substrate with InAlAs metamorphic buffers by gas source molecular beam epitaxy. The characteristics of InGaAs and InAlAs layers grown with different temperature schemes were investigated by high resolution X-ray diffraction reciprocal space maps, atomic force microscopy, photoluminescence and Hall-effect measurements. Results show that a higher growth temperature gradient of the InAlAs metamorphic buffers leads to a broader (004) reflection peak. The tilt angle between the epilayer and the substrate increases as well. The surface of the buffer layer becomes rougher. It indicates that the material defects increase and lattice relaxation becomes insufficient. In0.83Ga0.17As layers were grown on the InAlAs metamorphic buffer with a fixed growth temperature gradient. A higher growth temperature leads to a moderate full width at half maximum along the Q(x) direction of the (004) reflection, a stronger photoluminescence at 77 K, but a rougher surface of In0.83Ga0.17As. This indicates that the material defects can be suppressed at higher growth temperatures.