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X-ray diffraction, photoluminescence and secondary ion mass spectroscopy study of GaN films grown on Si(111) substrate by vacuum reactive evaporation

In this paper, GaN grown on Si(111) is reported using a GaN buffer layer by a simple vacuum reactive evaporation method. X-ray diffraction (XRD), photoluminescence (PL) measurement, Hall measurement and secondary ion mass spectroscopy (SIMS) results indicate that the single-crystalline wurtzite GaN was successfully grown on Si(111) substrate. A pronounced GaN(0002) peak appears in the XRD pattern. The full width at half maximum (FWHM) of the double-crystal x-ray rocking curve (DCXRC) for (0002) diffraction from the GaN epilayer is 18 arcmin. Annealing could heighten the PL and the GaN epilayer grown at 1050 °C exhibited the strongest PL. It was demonstrated in SIMS that both gallium and nitrogen distributed uniformly within the epilayer, while gallium segregated on the surface of the epilayer. The unintentionally doped films were n type with a carrier concentration of 1.76×1018 cm-3 and an electron mobility of 142 cm2 V-1 s-1. The high carrier concentration was associated with the impurities of silicon and oxygen and native defects existed in the epilayer. In situ cleaning was proved to be efficient for the removal of oxygen on the silicon substrate.