Effects of indium surfactant on the crystalline and optical properties of GaN during initial growth stage

Abstract

In this article, we report the effects of indium doping on crystalline and optical properties of GaN grown by metalorganic chemical vapor deposition during initial growth stage. Atomic force microscopy observations revealed that the In doping enhanced the lateral growth while the c-face growth rate was reduced. X-ray diffraction (XRD) and micro-Raman scattering measurements showed that the epilayers during this growth stage are nearly strain free. From XRD measurements, we found that In doping has increased the full width at half maximum values in both (0002) and (202̄4) ω-scan. Room temperature photoluminescence measurements show that In doping has enhanced the band-edge related emission by an order of magnitude compared to that of undoped GaN. Raman spectra indicate that In doping suppressed the misorientation of crystallites. In addition, a Raman mode occurred near 710 cm−1 in the In-doped GaN and has been assigned as the Fröhlich vibration.