An investigation of structural, optical and electrical properties of GaN thin films grown on Si( [formula omitted]) by reaction evaporation

Abstract

In this paper, gallium nitride (GaN) grown on Si(1 1 1) is reported using a GaN buffer layer by a simple reactive evaporation method. X-ray diffraction and transmission electron microscopy results indicated that the single crystalline wurtzite GaN was successfully grown on Si(1 1 1) substrate. The results of photoluminescence (PL) characterization showed that a band edge photoluminescence peak at 365 nm without yellow luminescence present was observed in the PL spectra at room temperature. The comparative analysis of PL spectra of GaN grown at different temperatures indicated both positive and negative impacts of substrate temperature on the photoluminescence of GaN, the GaN epilayer grown at 1050°C exhibited the strongest PL and annealing could heighten the PL. It was demonstrated in second ion mass spectroscopy that both of gallium and nitrogen distributed uniformly with the epilayer, while gallium seggregated on the surface of epilayer. The unintentionally doped films were n type with a carrier concentration of 5.27×10 17 cm −3 and an electron mobility of 238 cm 2 /V s. The high carrier concentration was associated with the impurities of silicon and oxygen and native defect existed in the epilayer.