Influence of the low-temperature buffer layer on InP epitaxial growth on GaAs substrates

Two-step growth method was used to grow InP epilayers directly on GaAs (001) substrates. By employing double-crystal x-ray diffraction (XRD) to characterize the epilayers and analyzing the value of full width at half maximum (FWHM) of ω scan rocking curve, we found the initial buffer layer act a key role on the quality of epilayers. Depending on optimizing the thickness and growth temperature of the initial buffer layers, we have succeeded in improving the crystallinity of InP epilayers. When the low temperature buffer layer was 10 nm thickness and grown at 450°C, the quality of InP epilayers for 1μm thickness were the best, its FWHM of XRD ω scan rocking curve was only 512 arcsec and 201arcsec for ω-2θ scans, the room temperature photoluminescence spectrum shows the band edge transition of InP, its central wavelength is 921nm and the FWHM is only 38 meV.These results indicate high quality of InP epilayers on GaAs substrates.