Boosting Performance of ZnO/(Bi,Sb)2Se3 Short-Wavelength Infrared Photodetector via ZnTe Hole-Transport Layer

Abstract

Infrared photodetectors based on (Bi,Sb)₂Se₃ alloys have attracted considerable attention owing to their tunable bandgaps and high carrier mobility, making them promising candidates for broadband detection. However, their performance is hindered by high dark current density and inefficient carrier extraction. Herein, ZnTe is introduced as a hole-transport layer (HTL) to reconfigure the band structure and fabricate a high-performance ZnO/(Bi,Sb)₂Se₃/ZnTe photodetector. By systematically tuning the ZnTe HTL thickness, a 53% enhancement in EQE (16.2% at 1300 nm) and a 50% reduction in dark current density (97.4 µA cm⁻², at −0.5 V) are achieved compared to HTL-free devices. SCAPS simulation elucidates that the designed (Bi,Sb)₂Se₃/ZnTe heterojunction effectively suppresses electron backflow while enhancing hole extraction, thereby boosting performance. Therefore, the optimized device exhibits a notably fast response time (12/107.5 ns rise/fall) and a wide linear dynamic range (LDR, 96 dB). Additionally, unencapsulated devices retain 97.7% of their initial performance after 322 h of operating at 90 °C and withstand extreme annealing at 150°C, surpassing many state-of-the-art detectors. This approach provides a scalable, low-cost, and eco-friendly strategy for developing high-performance, high-speed, and high-stability infrared photodetection systems.