Near-Infrared InGaN Alloys Grown on High-In-Composition InGaN Buffer Layer

Near-infrared InGaN alloys were grown on a strain-relaxed high-In-composition InGaN buffer layer based on GaN/sapphire substrate by plasma assisted molecular beam epitaxy. The In compositions of the InGaN light emitting layer and buffer layer determined by X-ray diffraction analysis are 56.7 and 61.1%, respectively. Transmission electron microscopy result shows that no dislocations newly generated at the interface of the InGaN structure layer and the underlying InGaN buffer layer can be observed obviously. The cathodoluminescence spectra exhibit two strong emission peaks at the near-infrared wavelengths of 1090 and 1200 nm, which can be attributed to intrinsic transition and recombination processes of the fabricated InGaN alloys according to the calculation using the energy versus composition equation with a reasonable bowing parameter.