Realization of p-type In_1.75Sb_0.25Se₃ alloys for short-wave infrared photodetectors

The narrow-gap semiconductors (NGSs) with two-dimensional (2D) layered structures provide fundamental advantages, such as low noise and high quantum efficiency, for short-wave infrared (SWIR) optoelectronic devices. However, realizing high-performance photodetectors based on 2D NGSs with high photoresponsivity, low noise, and fast response speed remains a challenge. Here, we present the design, preparation, and characterization of an In 2(1− x ) Sb 2 x Se 3 SWIR photodetector. Trivalent antimony (Sb 3+ ) substitutional doping not only induced the β′-β phase transition at room temperature but also made the alloy a good candidate for the p-type semiconductor. Moreover, the individual In 1.75 Sb 0.25 Se 3 nanoflake realized an excellent photoresponse in a broadband range from visible (405 nm) to SWIR (1550 nm) light with a photoresponsivity of 134 A W −1 and a detectivity of 1.82 × 10 7 Jones. These performances were superior to the reported In 2 Se 3 , Sb 2 Se 3 , and other In or Sb selenide photodetectors, which indicated that the β-In 2(1− x ) Sb 2 x Se 3 alloy may provide a potential building block for short-wave infrared photodetectors.