| Summary: | ZnGa<sub>2</sub>O<sub>4</sub> is a promising semiconductor for developing high-performance deep-ultraviolet photodetectors owing to a number of advantageous fundamental characteristics. However, Zn volatilization during the ZnGa<sub>2</sub>O<sub>4</sub> growth is a widely recognized problem that seriously degrades the film quality and the device performance. In this study, we report the synthesis of epitaxial ZnGa<sub>2</sub>O<sub>4</sub> thin films by pulsed laser deposition using a non-stoichiometric Zn<sub>1+<i>x</i></sub>Ga<sub>2</sub>O<sub>4</sub> target. It is found that supplementing excessive Zn concentration from the target is highly effective to stabilize stochiometric ZnGa<sub>2</sub>O<sub>4</sub> thin films during the PLD growth. The influence of various growth parameters on the phase formation, crystallinity and surface morphology is systematically investigated. The film growth behavior further impacts the resulting optical absorption and thermal conductivity. The optimized epitaxial ZnGa<sub>2</sub>O<sub>4</sub> film exhibits a full width at half maximum value of 0.6 degree for a 120 nm thickness, a surface roughness of 0.223 nm, a band gap of 4.79 eV and a room-temperature thermal conductivity of 40.137 W/(m⋅K). This study provides insights into synthesizing epitaxial ZnGa<sub>2</sub>O<sub>4</sub> films for high performance optoelectronic devices.
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