Fabrication of High‐Responsivity Sb₂Se₃‐Based Photodetectors through Selenization Process

Abstract Sb₂Se₃ has great potential for applications in near‐infrared sensors because of its narrow bandgap, environmental friendliness, and high absorption coefficient. However, the low conductivity of Sb₂Se₃ is an obstacle to the further development of high‐performance optoelectronic devices. In this study, to address this challenge, the selenization process is adopted. The incorporation of Se atoms into Sb₂Se₃ facilitates the crystallization of the films and the formation of [hk0]‐textured grains at a lower temperature than unselenized Sb₂Se₃. The selenized films possess larger grains than the unselenized ones at the same temperature. X‐ray photoelectron spectroscopy (XPS) results show that annealing causes the generation of donor‐like point defects (e.g., V_se and Sb_Se) and SeO₂. The 250 °C‐annealed selenized Sb₂Se₃‐based photodetectors (PDs) have a high responsivity of 1130 mW A⁻¹ and a specific detectivity of 4.62 × 10¹¹ Jones. The PDs exhibit a fast response time (i.e., rise/fall time of 4.54 ms/8.50 ms), sensitivity of 94.2 at 20 mW cm⁻², and external quantum efficiency of 155% at 200 µW cm⁻². Further, the selenized PDs have good stability to moisture and air. Based on the XPS, X‐ray diffraction, and transmission electron microscope results, the improved performance of the selenized Sb₂Se₃‐based PDs is described and discussed.