Growth of homoepitaxial Ⅲ-nitride layers on bulk GaN single crystals by molecular-beam epitaxy

摘要

Undoped-GaN, Mg-doped GaN, undoped-AlGaN, and undoped-AlInGaN epilayers have been grown on bulk GaN single crystals with single polar surfaces by radio-frequency molecular-beam epitaxy method. The full-widths at half maximum of X-ray diffraction peaks taken from GaN epilayers were very small. When the growth was carried out only on Ga-faces of bulk GaN single crystals, p-GaN epilayers without any post-treatments and AlGaN epilayers on higher Al composition were obtained. Photoluminescence (PL) spectra at different temperatures ranged from 8 to 300 K were measured for the undoped-Al_(0.10)In_(0.05)Ga_(0.85)N epilayer on Ga-face. The PL intensity of undoped-Al_(0.10)In_(0.05)Ga_(0.85)N epilayer at RT was only 1 order of magnitude smaller than that at 8 K, indicating localization effects by In atoms.