Heteroepitaxial Growth of α‑GaO by MOCVD on ‑, ‑, ‑, and ‑Planes of Sapphire.

GaO thin films were deposited simultaneously on (112̅0) -plane, (101̅0) -plane, (0001) -plane, and (011̅2) -plane sapphire substrates using metal-organic chemical vapor deposition (MOCVD) and characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The different surface energy and strain conditions imposed by each sapphire plane make the choice of substrate orientation critical to the stabilization of the α-phase. β-GaO nucleation was found to be preferential over α-GaO on sapphire orientations with <11̅00> α-AlO present (c- and -planes) when grown under the same conditions.