Investigation of alloy Composition Fluctuation in Indium Gallium Nitride (InGaN) Tenary Films

Abstract

In a bid to reduce the rate of nonradiative recombination in InGaN LEDs, the optical and structural properties of the ternary films were investigated by temperature-dependent photoluminescence (PL), high-resolution X-ray diffraction (HRXRD) and high-resolution electron microscopy (HREM). The results show that the temperature-dependent PL intensity of the InGaN film is similar to that of the disordered alloys, which is thought to be due to local alloy compositional fluctuations (ACF) in the epilayer. HRXRD measurement reveals that, there are In-rich and In-poor phases in the film and HREM observation, on the other hand, demonstrates that nanoclusters formed in the epilayer. Therefore the experimental results support the existence of ACF in the epilayers which causes nonradiative recombination.