Self‐Powered SWIR Photodetector Based on Se 0.2 Te 0.8 Thin‐Film Heterojunction

Abstract

ABSTRACT High‐performance short‐wave infrared (SWIR) photodetectors typically rely on single‐crystalline germanium and III–V semiconductors. However, their high material costs and complex fabrication requirements hinder large‐area integration and cost‐effective SWIR technologies. Here, we report a scalable vertical heterojunction employing magnetron‐sputtered Se 0.2 Te 0.8 thin films with good large‐area uniformity. By exploiting the intrinsic SWIR bandgap absorption of Se 0.2 Te 0.8 together with the built‐in electric field of the vertical heterojunction, the device exhibits a high signal‐to‐noise ratio, robust environmental stability and efficient self‐powered operation at room‐temperature across multiple telecommunication bands. Under zero bias illumination at 1550 nm, it achieves a responsivity of 32 mA/W, a specific detectivity of 5 × 10 9 Jones, and a microsecond‐scale response time. Single‐pixel scanning experiments further demonstrate its potential for SWIR optical communication and imaging. This work provides a scalable route towards high‐performance, low‐power SWIR photodetection and imaging at room temperature.