Growth and characterization of α-Ga₂O₃ on sapphire and nanocrystalline β-Ga₂O₃ on diamond substrates by halide vapor phase epitaxy Available to Purchase

Halide vapor phase epitaxial (HVPE) Ga₂O₃ films were grown on c-plane sapphire and diamond substrates at temperatures up to 550 °C without the use of a barrier dielectric layer to protect the diamond surface. Corundum phase α-Ga₂O₃ was grown on the sapphire substrates, whereas the growth on diamond resulted in regions of nanocrystalline β-Ga₂O₃ (nc-β-Ga₂O₃) when oxygen was present in the HVPE reactor only during film growth. X-ray diffraction confirmed the growth of α-Ga₂O₃ on sapphire but failed to detect any β-Ga₂O₃ reflections from the films grown on diamond. These films were further characterized via Raman spectroscopy, which revealed the β-Ga₂O₃ phase of these films. Transmission electron microscopy demonstrated the nanocrystalline character of these films. From cathodoluminescence spectra, three emission bands, UVL′, UVL, and BL, were observed for both the α-Ga₂O₃/sapphire and nc-Ga₂O₃/diamond, and these bands were centered at approximately 3.7, 3.2, and 2.7 eV.