Pure-phase κ-Ga2O3 layers grown on c-plane sapphire by halide vapor phase epitaxy

Abstract

κ-gallium oxide (Ga 2 O 3 ) layers were hetero-epitaxially grown on c-plane sapphire substrates by halide vapor phase epitaxy (HVPE). Pure (001)-oriented κ-Ga 2 O 3 with high crystal quality was obtained with this method on sapphire at 800 °C. Furthermore, three in-plane rotational domains in the κ-Ga 2 O 3 layers on sapphire substrates were revealed by XRD ϕ-scan and two typical domain regions were observed by high resolution transmission electron microscopy with selected area electron diffraction . The in-plane epitaxial relationship was proposed to be (010) κ-Ga 2 O 3 //(10 1 ‾ 0) Al 2 O 3 and (110) κ-Ga 2 O 3 //(1 1 ‾ 00) Al 2 O 3 . The bandgap was calculated to be ~5.02eV from the optical transmittance spectrum. • Pure-phase κ-Ga 2 O 3 layers have been grown on c-plane sapphire substrates by HVPE. • The orthorhombic structure has been confirmed by XRD Ф-scans and HRTEM analysis. • In-plane rotational domains of κ-Ga 2 O 3 have been observed and revealed by HRTEM .