Selenization Induced Surface Modification of SnO _x for High‐Performance SnO _x /Te _0.73 Se _0.27 Short‐Wavelength Infrared Photodetection

Abstract Short‐wave infrared (SWIR) detectors are becoming increasingly vital in areas such as autonomous driving, food inspection, medical diagnostics, and scientific exploration. Recently, Te x Se 1–x has exhibited exceptional promise for infrared photodetection. However, Te x Se 1–x ‐based devices still struggle with excessively high dark current and subpar performance. This work presents an interface engineering via selenization in the SnO x /Te 0.73 Se 0.27 heterojunction SWIR photodetector. The post‐selenization modifies the surface properties of SnO x , reduced the interface defect density, and enlarged the built‐in potential in the junction. Moreover, this interface engineering leads to improved band alignment, facilitating charge transport and collection. As a result, the improved device achieves a reduced dark current density from 1.6 × 10 −6 A cm −2 to 1.4 × 10 −7 A cm −2 at zero bias voltage. The device exhibits a broad‐spectrum response ranging from 300 to 1700 nm, with a room‐temperature responsivity of 0.33 A W −1 at 980 nm, a specific detectivity of 6.61 × 10 10 Jones, a ‐3 dB bandwidth of 120 kHz, and a linear dynamic range of 110 dB. Moreover, its applications in the short‐wave infrared single‐pixel imaging is demonstrated.