Low-temperature GaN growth on silicon substrates by single gas-source epitaxy and photo-excitation

We report a unique low-temperature growth method for epitaxial GaN on Si(111) substrates via a ZrB2(0001) buffer layer. The method utilizes the decomposition of a single gas-source precursor (D2GaN3)3 on the substrate surface to form GaN. The film growth process is further promoted by irradiation of ultraviolet light to enhance the growth rate and ordering of the film. The best epitaxial film quality is achieved at a growth temperature of 550°C with a growth rate of 3nm∕min. The films exhibit intense photoluminescence emission at 10K with a single peak at 3.48eV, indicative of band-edge emission for a single-phase hexagonal GaN film. The growth process achieved in this study is compatible with low Si processing temperatures and also enables direct epitaxy of GaN on ZrB2 in contrast to conventional metalorganic chemical vapor deposition based approaches.