Growth of high-quality AlGaN epitaxial films on Si substrates

High-quality AlGaN epitaxial films have been grown on Si(1 1 1) substrates by metal-organic chemical vapor deposition through introducing an AlN layer followed by a high Al composition AlGaN buffer layer, together with optimizing the growth temperature to promote the dislocations reduction. The as-grown ∼400 nm-thick AlGaN epitaxial films with optimized growth temperature of 980 °C reveal high crystalline quality with a full-width at half-maximum for AlGaN(0 0 0 2) of 0.29° and smooth surface with a root-mean-square surface roughness of 0.76 nm. This work provides an effective approach for the growth of high-quality AlGaN epitaxial films in the application of ultraviolet lasers and detectors.