2D/1D PbI2/Sb2S3 van der Waals heterojunction for highly sensitive and broadband photodetectors

Abstract

Broadband photodetectors have received significant scientific interest due to their high optical gain with low energy consumption. PbI₂ is an important 2D semiconductor material for electronic and optoelectronic devices. However, its limited detection capability towards visible light hinders its wide applications in the optoelectronic field. Herein, we report a novel van der Waals (vdW) 2D/1D PbI₂/Sb₂S₃ heterojunction photodetector exhibiting broadband spectral response from 400 to 750 nm. In comparison to individual PbI₂ and Sb₂S₃ devices, the heterojunction photodetector manifests much higher responsivity (156.3 and 120.4 A W⁻¹), external quantum efficiency (4.4 × 10⁴% and 2.1 × 10⁴%), and detectivity (3.16 × 10¹³ and 2.45 × 10¹² Jones) under 445 and 730 nm illumination, respectively. Experimental characterizations and theoretical calculations reveal the significantly enhanced photoelectric properties can be primarily ascribed to the effective separation of photogenerated electron/hole pairs facilitated by the type-II vdW heterojunction mediated by defect states. This work can provide some new insights into the fabrication of novel hybrid van der Waals heterojunctions and their applications in the optoelectronic fields.