Epitaxial Growth of Alpha Gallium Oxide Thin Films on Sapphire Substrates for Electronic and Optoelectronic Devices: Progress and Perspective

The demand for high-efficient and robust power semiconductors in harsh environments such as high temperature and high voltage has been enlarged with the fast development of the industry. Gallium oxide (Ga 2 O 3 ) with a larger bandgap energy of 4.8–5.3 eV than Si, SiC, and GaN is a promising material suitable for next-generation power devices. Among the Ga 2 O 3 ’s phases, corundum structured α-Ga 2 O 3 has attracted much attention, benefiting from the epitaxial growth on cheap sapphire substrate and the existence of p-type materials with the same crystal structure. This paper comprehensively reviews the progress on the epitaxial growth of α-Ga 2 O 3 thin films and the fabrication of α-Ga 2 O 3 -based electronic and optoelectronic devices. First, state-of-the-art technologies for improving the crystal quality of α-Ga 2 O 3 depending on growth methods are presented. Secondly, the current research level of growth of n-type doped α-Ga 2 O 3 is comprehended. Finally, the recent progress of electronic and optoelectronic devices, including Schottky diodes, field-effect transistors, and solar-blind photodetectors, is summarized. Graphical abstract