Effect of Si doping on the structural and the optical properties in high-quality AlxGa1-xN/GaN heterostructures grown by metalorganic chemical vapor deposition

AlxCa1-xN/GaN films were grown on sapphire substrate by using rnetalorganic chemical vapor deposition, and their structural, electrical, and optical properties were systematically investigated by using atomic force microscopy, high-resolution X-ray diffraction (HRXRD), Hall measurements, and photoluminescence (PL). The strain states and the mosaic properties of the AlGaN and GaN layers were studied by using the (10(.)5) asymmetric reciprocal space maps (RSMs). From the RSMs, we confirmed that the crystal lattice of the Al0.13Ga0.89N film was fully strained and that the crystal quality was good. From the PL and the HRXRD data, we observed that a. certain range of Si doping could cause a small variation of Al incorporation during the growth of the AlGaN film, resulting in a variation in the Al content and the crystal quality of the AlGaN layer. From the results, we conclude that moderate Si-doping improves the optical and the structural properties of Al0.11Ga0.89N films.