Abstract: The exploration of novel materials stands as the linchpin in the advancement of the next-generation photodetectors. Group III-VI compound semiconductors have attracted extensive research enthusiasm due to their numerous advantages, including simple crystal structure, environmentally friendly composition, and outstanding air stability. Nevertheless, the exploration of the optoelectronic properties of Ga₂Se₃ remains relatively scarce to date as compared to other group III-VI compound semiconductors, primarily hampered by the challenges in synthesis. As an endeavor, this study has embarked on an exhaustive exploration of the physical and optoelectronic attributes of Ga₂Se₃ from both theoretical and experimental aspects. Initiating with an in-depth analysis on the electronic structure through systematical first-principles calculations, this study has determined that Ga₂Se₃ bears a sizable bandgap up to ≈ 1.96 eV as well as an optimal carrier mobility of ≈ 7081.97 cm² V^-1 s^-1. In addition, the carrier transport has been revealed to be highly anisotropy, making it compelling in multifunctional optoelectronic devices. Following this, a two-step synthetic methodology has been formulated to achieve the preparation of Ga₂Se₃. Notably, the corresponding Ga₂Se₃-based photodetector exhibits distinct photoresponse to 405 nm violet light, boasting a responsivity of 0.326 mA/W, an external quantum efficiency of 0.1 %, and a specific detectivity of 8.73 × 10⁹ Jones. Furthermore, the Ga₂Se₃ photodetectors have been used as the sensing components to realize proof-of-concept optoelectronic imaging and optical communication applications, demonstrating exceptional anti-interference capability to white light interference. In the end, polarization-resolved photoresponse has been unveiled. On the whole, this study provides a new material platform and a distinct pathway for broadening the horizons of optoelectronic research.

Key words: Ga₂Se₃, Photodetectors, Pulsed-laser deposition, Anti-interference imaging, Anti-interference optical communications