High-performance self-powered photodetectors based on Te/Si heterojunctions

Abstract

Due to excellent electrical transport and environmental stability, tellurium (Te) exhibits significant potential for developing high-performance self-powered photodetectors. However, the substantial dark current arising from the intrinsic high conductivity and slow response speeds due to the absence of a built-in field severely limit its further practical application. High-performance Te/Si heterojunction photodetectors are reported in this study. The textured Te films are deposited on n-Si by the sputtering technique and Te/Si heterojunction photodetectors are fabricated. Due to the formation of the built-in electric field at the heterointerface, the Te/Si heterojunction photodetector exhibits a high responsivity of 370 mA W⁻¹ and a detectivity of 2.08 × 10¹² Jones under 405 nm illumination and 0 V bias voltage. Additionally, it also shows a 3 dB cut-off frequency of ∼5 kHz, rapid photoresponse rise/fall times of approximately 135/142 μs, and excellent repeatability and stability. The results demonstrate that the Te/Si heterojunctions hold significant potential in high-performance, self-powered and high-speed photodetectors.