Secondary ion mass spectroscopy and photoluminescence investigations on the GaN epilayer grown on Si substrate

in this paper, the growth GaN epilayer on the Si substrate by a novel vacuu m reaction method rather than metal-organic chemical vapor deposition and m olecular beam epitaxy is reported. The effects of growth temperature and an nealing process on the photoluminescence (PL) of GaN epilayer were investig ated. Annealing could weaken the PL and the GaN epilayer grown at 1050 degr ees C exhibited the strongest FL. It was demonstrated in secondary ion mass spectroscopy that both gallium and nitrogen were distributed uniformly wit hin the epilayer, while gallium was segregated on the surface of epilayer. The high carrier concentration (1.7 x 10(18)/cm(3)) was associated with the impurities of silicon and oxygen and native defects existing in the epilay er. In-situ cleaning was proved to be efficient for the removal of oxygen o n the silicon substrate.