(Bi,Sb)2Se3 Alloy Thin Film for Short‐Wavelength Infrared Photodetector and TFT Monolithic‐Integrated Matrix Imaging

Abstract

AbstractShort‐wavelength infrared photodetectors play a significant role in various fields such as autonomous driving, military security, and biological medicine. However, state‐of‐the‐art short‐wavelength infrared photodetectors, such as InGaAs, require high‐temperature fabrication and heterogenous integration with complementary metal‐oxide‐semiconductor (CMOS) readout circuits (ROIC), resulting in a high cost and low imaging resolution. Herein, for the first time, a low‐cost, high‐performance, high‐stable, and thin‐film transistor (TFT) ROIC monolithic‐integrated (Bi,Sb)2Se3 alloy thin‐film short‐wavelength infrared photodetector is reported. The (Bi,Sb)2Se3 alloy thin‐film short‐wavelength infrared photodetectors demonstrate a high external quantum efficiency (EQE) of 21.1% (light intensity of 0.76 µW cm−2) and a fast response time (3.24 µs). The highest EQE is about two magnitudes than that of the extrinsic photoconduction of Sb2Se3 (0.051%). In addition, the unpackaged devices demonstrate high electric and thermal stability (almost no attenuation at 120 °C for 312 h), showing potential for in‐vehicle applications that may experient such a high temperature. Finally, both the (Bi,Sb)2Se3 alloy thin film and n‐type CdSe buffer layer are directly deposited on the TFT ROIC (with a 64 × 64‐pixel array) with a low‐temperature process and the material identification and imaging applications are presented. This work is a significant breakthrough in ROIC monolithic‐integrated short‐wavelength infrared imaging chips.