Studying of linearly graded buffer layer effect on quality of InGaAs on GaAs substrate

There has been extensive applcations in the area of photoelectronic device because InGaAs grown on the GaAs substrate have advantageous photoelectronic performance and adjustable band gap. The main obstacle to acquiring high crystalline quality of InGaAs grown on GaAs substrate comes from the large lattice mismatch between InGaAs overlayer and GaAs substrate. It is particularly detrimental to the structure and photoelectronic property of InGaAs thin films that lager roughness of surface and high misfit dislocation density is introduced because of the defect onset during the growth. The In_0.1Ga_0.9As layers with and without linearly graded buffer layers grown on GaAs substrate had been studied. The investigations were performed by applying atomic force microscopy (AFM), high resolution X-ray diffractometry (HR XRD). A linearly graded buffer layer is effective for lowering the misfit dislocation density in In_0.1Ga_0.9As layers on a GaAs substrate, but it can not end the dislocation in buffer layer completely. All above-mentioned is also confirmed in HRXRD results.