Broadband photodetector based on CdS/Sb2Se3 heterojunction

Abstract

Broadband photodetectors have attractive application prospects in optical communication, image sensing, and environmental monitoring. Though narrow band gap semiconductors with good stability and low cost is an ideal candidate for achieving a relatively wide spectral response, heterojunction structures are usually proposed for constructing high-performance photodetectors with a broader spectral response and more fascinating optical-electrical characteristics. Here, a CdS/Sb₂Se₃ heterojunction photodetector was fabricated by magnetron sputtering, and morphology, microstructure, and photoelectric detection performance were studied. It is revealed that a high quality CdS and Sb₂Se₃ film with good crystallinity were gained by utilizing our growth parameters. Moreover, a CdS surface consisting of homogeneous nano islands was observed. In particular, CdS/Sb₂Se₃ heterojunction exhibits an ultra-wide photoelectric response range (365 nm ~ 1064 nm) and an ultra-fast photoresponse (< 0.2 ms). Our results proposed that these improvements on photoelectric detection performance of heterojunction is attributed to the microstructure of deposited films. This study provides a new prototype for the applications of broadband photodetector.