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

Abstract

Abstract Sb 2 Se 3 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 Sb 2 Se 3 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 Sb 2 Se 3 facilitates the crystallization of the films and the formation of [ hk 0]‐textured grains at a lower temperature than unselenized Sb 2 Se 3 . 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 SeO 2 . The 250 °C‐annealed selenized Sb 2 Se 3 ‐based photodetectors (PDs) have a high responsivity of 1130 mW A −1 and a specific detectivity of 4.62 × 10 11 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 Sb 2 Se 3 ‐based PDs is described and discussed.