Heteroepitaxial Growth of NiO Thin Films on (‐201) β‐Ga₂O₃ by Mist Chemical Vapor Deposition

The growth of NiO epitaxial thin films on (‐201) β‐Ga 2 O 3 by mist chemical vapor deposition (CVD) and the effects of carrier gas selection (N 2 and O 2 ) and substrate preannealing treatment on the structural and morphological properties on the grown thin films are explored. X‐ray diffraction analysis reveals successful epitaxial growth with the orientation relationship (111) NiO [0‐11] || (‐201) β‐Ga 2 O 3 [010]. As a carrier gas, O 2 results in single‐domain NiO films while N 2 leads to the formation of rotational domains. Atomic force microscopy and field‐emission scanning electron microscopy confirm the lateral growth of NiO films, thus highlighting the importance of substrate preannealing at 1200 °C in oxygen atmosphere to obtain flat, high‐quality films. The results demonstrate that the method of mist CVD combined with appropriate substrate preparation and carrier gas selection is effective for the growth of high‐quality NiO/β‐Ga 2 O 3 heterostructures. This achievement opens new possibilities for the development of wide‐bandgap p–n heterojunctions, potentially advancing the field of high‐power oxide‐based electronic devices.