A self-powered ultraviolet photodetector based on TiO2/Ag/ZnS nanotubes with high stability and fast response

Abstract

Ag nanoparticles (NPs) have been successfully deposited onto TiO₂ nanotubes (NTs) via a photochemical method and ZnS layer was further fabricated on the surface of the TiO₂/Ag NTs at room temperature. The morphology, composition and structure of the as-prepared samples were analyzed. A self-powered UV photodetector (UVPD) based on the TiO₂/Ag/ZnS NTs has been constructed. When exposed to UV light, the TiO₂/Ag/ZnS NTs UVPD manifests a higher photocurrent density than that of the TiO₂ and TiO₂/Ag NTs UVPDs at a bias of zero V. The TiO₂/Ag/ZnS NTs UVPD also reveals a splendid linear optical signal response. Meanwhile, it is noteworthy that the TiO₂/Ag/ZnS NTs UVPD has excellent stability and repeatability, and the rise time and decay time are 0.16 s and 0.18 s, respectively. Moreover, a possible UV detection mechanism of the TiO₂/Ag/ZnS NTs UVPD is proposed.