X-ray diffraction, photoluminescence and secondary ion massspectroscopy study of GaN films grown on Si(111) substrate by vacuum reactiveevaporation

Abstract

In this paper, GaN grown on Si(111) is reported using a GaN bufferlayer by a simple vacuum reactive evaporation method. X-ray diffraction (XRD),photoluminescence (PL) measurement, Hall measurement and secondary ion massspectroscopy (SIMS) results indicate that the single-crystalline wurtzite GaNwas successfully grown on Si(111) substrate. A pronounced GaN(0002) peakappears in the XRD pattern. The full width at half maximum (FWHM) of thedouble-crystal x-ray rocking curve (DCXRC) for (0002) diffraction from the GaNepilayer is 18 arcmin. Annealing could heighten the PL and the GaN epilayergrown at 1050 °C exhibited the strongest PL. It was demonstrated inSIMS that both gallium and nitrogen distributed uniformly within the epilayer,while gallium segregated on the surface of the epilayer. The unintentionallydoped films were n type with a carrier concentration of1.76×1018 cm-3 and an electron mobility of 142 cm2 V-1 s-1. The high carrier concentration wasassociated with the impurities of silicon and oxygen and native defectsexisted in the epilayer. In situ cleaning was proved to be efficientfor the removal of oxygen on the silicon substrate.