Growth temperature induced effects in non-polar a-plane GaN on r-plane sapphire substrate by RF-MBE

Abstract: Non-polar a-plane GaN films were grown on an r-plane sapphire substrate by plasma assisted molecular beam epitaxy (PAMBE). The effect of growth temperature on structural, morphological and optical properties has been studied. The growth of non-polar a-plane (11−20) orientation of the GaN epilayers were confirmed by high resolution X-ray diffraction (HRXRD) study. The X-ray rocking curve (XRC) full width at half maximum of the (11−20) reflection shows in-plane anisotropic behavior and found to decrease with increase in growth temperature. The atomic force micrograph (AFM) shows island-like growth for the film grown at a lower temperature. Surface roughness has been decreased with increase in growth temperature. Room temperature photoluminescence shows near band edge emission at 3.434–3.442eV. The film grown at 800°C shows emission at 2.2eV, which is attributed to yellow luminescence along with near band edge emission. [ABSTRACT FROM AUTHOR]