Carrier recombination suppression and transport enhancement enable high-performance self-powered broadband Sb2Se3 photodetectors

Abstract

Antimony selenide (Sb2Se3) is a promising candidate for photodetector applications boasting unique material benefits and remarkable optoelectronic properties. Achieving high-performance self-powered Sb2Se3 photodetector through a synergistic regulation of absorber layer and heterojunction interface demonstrates great potential and needs essential investigation. In this study, an effective two-step thermodynamic/kinetic deposition technique containing sputtered and selenized Sb precursor is implemented to induce self-assembled growth of Sb2Se3 light absorbing thin film with large crystal grains and desirable [hk1] orientation, presenting considerable thin-film photodetector performance. Furthermore, aluminum (Al3+) cation dopant is introduced to modify the optoelectronic properties of CdS buffer layer, and further optimize the Sb2Se3/CdS (Al) heterojunction interface quality. Thanks to the suppressed carrier recombination and enhanced carrier transport kinetics, the champion Mo/Sb2Se3/CdS (Al)/ITO/Ag photodetector exhibits self-powered and broadband characteristics, accompanied by simultaneously high responsivity of 0.9 A W−1 (at 11 nW cm−2), linear dynamic range of 120 dB, impressive ON/OFF switching ratio over 106 and signal-to-noise ratio of 109, record total noise determined realistic detectivity of 4.78 × 1012 Jones, and ultra-fast response speed with rise/decay time of 24/75 ns, representing the top level for Sb2Se3-based photodetectors. This intriguing work opens up an avenue for its self-powered broadband photodetector applications.