Characterization of InGaAs/InP single quantum well structure on GaAs substrate with metamorphic buffer grown by molecular beam epitaxy

Abstract

InGaAs/InP single quantum well (SQW) structure grown by solid source molecular beam epitaxy has been investigated to assess the quality of various low-temperature (LT) metamorphic buffer schemes developed on GaAs substrate. Atomicforce microscope, X-ray diffraction and photoluminescence measurements have been used to characterize a series of samples. It is found that the buffer layer scheme consisting of LT grown GaAs and InP (20 nm thick each grown at 400°C) and normal temperature grown InP (1.5 μm, 480°C) was effective in improving the crystalline quality. The full-width at half-maximum values obtained from the XRD ϖ scan around the InP peak and the PL linewidth of the SQW peak were 519 arcsec and 50 meV, respectively, for the optimized structure. The optimized metamorphic buffer scheme was further tested by characterizing the SQW structure as a function of thickness and growth rate of the InP buffer layer structure. Results indicate that the reduction of thickness and growth rate will bring about larger mosaicity and greater surface roughness.