Investigation of substrate orientation dependence for the growth of GaN on GaAs (111)A and (111)B surfaces by metalorganic hydrogen chloride vapor-phase epitaxy

It was found that a 50-nm-thick GaN buffer layer grown by metalorganic hydrogen chloride vapor-phase epitaxy (MOHVPE) at 550 degrees C on a GaAs (111)A surface did not deteriorate even after subsequent heating in an NH3 ambient up to 1000 degrees C, whereas numerous pinholes were formed when the buffer layer was grown on a GaAs (111)B surface. In addition, serious arsenic (As) desorption from the GaAs substrate occurred through the pinholes. A single crystal hexagonal GaN layer with a mirror-like surface can be grown at 1000 degrees C on the 50-nm-thick GaN buffer layer grown at 550 degrees C on the GaAs (111)A surface, as confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The full-width at half maximum (FWHM) of the omega mode scan for the GaN (0002) plane was 1450 arcsec. Photoluminescence (PL) measurement showed a sharp band-edge emission at 363.1 nm with a FWHM of 96 meV at room temperature.