Preparation of high-quality CuGa2O4 film via annealing process of Cu/β-Ga2O3

High-quality CuGa2O4 film has been successfully prepared on β-Ga2O3 ( $$ \bar{2}01 $$ ) single-crystal substrate via annealing method at 1050 °C temperature under air after evaporating Cu film. According to high-resolution X-ray diffraction measurement results, the crystallinity of CuGa2O4 film and epitaxial relationship between CuGa2O4 film and β-Ga2O3 ( $$ \bar{2}01 $$ ) substrate was confirmed. The CuGa2O4 film has the preferred [111] orientation and the full-width half-maximum of CuGa2O4 film of (222) peak is 0.228°. The CuGa2O4 (111) plane is parallel to the β-Ga2O3 ( $$ \bar{2}01 $$ ) plane (out-plane) and the CuGa2O4 [ $$ \bar{1}\bar{1}2 $$ ], and [110] directions are parallel to the β-Ga2O3 [102] and [010] directions (in-plane), respectively. In addition, the lattice mismatch between CuGa2O4 [111] and β-Ga2O3 ( $$ \bar{2}01 $$ ) substrate has also been calculated. These results suggest that high-quality and preferred orientation CuGa2O4 film can be prepared on β-Ga2O3 ( $$ \bar{2}01 $$ ) substrate with Cu film.