High-Quality InGaN Films Grown by Hot-Wall Epitaxy with Mixed (Ga+In) Source

A simple mixed source (gallium and indium metals) method was used in a hot-wall epitaxial system to grow InGaN films on sapphire with thick (∼1.5 µm) and thin (∼3 nm) GaN buffer layers. Indium incorporation was controlled independently by the substrate temperature, the N 2 partial pressure and the mixed source temperature. High-quality InGaN films were obtained, showing strong near-band-edge emission peaks ranging from 370 to 465 nm and narrow X-ray rocking curve full-width at half maximum for InGaN (0002) of 7.03 arcmin. Non-resonant Raman shift of InGaN layers was clearly observed for the first time.