Controlled Epitaxial Growth of (hk1)-Sb₂Se₃ Film on Cu₉S₅ Single Crystal via Post-Annealing Treatment for Photodetection Application

Antimony selenide (Sb2Se3) is a promising semiconductor for photodetector applications due to its unique photovoltaic properties. Achieving optimal carrier transport in (001)-Sb2Se3 by the material of contacting substrate requires in-depth study. In this paper, the induced growth of Sb2Se3 films from (hk0) to (hk1) planes is achieved on digenite (Cu9S5) films by post-annealing treatment. The flake-like and flower-like morphologies on the surface of Sb2Se3 films are caused by different thicknesses of the Cu9S5 films, which are related to the (hk0) and (hk1) planes of Sb2Se3 surface. The epitaxial growth of Sb2Se3 films on (105)-Cu9S5 surfaces exhibits thickness dependence. The results inform research into the controlled induced growth of low-dimensional materials. The device of Sb2Se3/Cu9S5/Si has good broadband response (visible to near-infrared), self-powered characteristics, and stability. As the crystalline quality of the Sb2Se3 film increases along the (hk1) plane, the carrier transport is enhanced correspondingly. Under the 980 nm light irradiation, the device has an excellent switching ratio of 2 x 10(4) at 0 bias, with responsivity, detectivity, and response time up to 17 mu A W-1, 1.48 x 10(7) Jones, and 355/490 mu s, respectively. This suggests that Sb2Se3 is suitable for self-powered photodetectors and related optical and optoelectronic devices.