Zinc Stannate Nanocrystal–Based Ultrarapid‐Response UV Photodetectors

Abstract Ternary‐oxide nanostructures are the most investigated as promising candidates for ultraviolet (UV) photodetectors (PDs) due to composition tunable bandgap and better photoconductivity. However, the assembled film–based UV PDs generally exhibit poor response speed because the internal defects of nanostructures and the discontinuity of assembled film obstruct transport of charges. Herein, a single‐crystal Zn₂SnO₄ (ZTO) nanocrystal (NC)–assembled film UV photodetector is reported, improving the response speed several tens of times (τ_rise ≈ 0.2 ms, τ_decay ≈ 0.43 ms). The I_light/I_dark ratio of the UV PD is over 10³. The ZTO NCs, with the bandgap of 3.9 eV, are prepared by laser ablation in liquid combined with hydrothermal reaction. The combination and dissociation of Zn–Sn–O ternary oxide are investigated to guarantee that single‐crystal ZTO NCs have high purity, clean surface, high specific surface area. Moreover, the NC‐assembled film is highly compact and continuous, which outperforms the conventional 1D nanostructures. This work provides a reliable novel approach to greatly improve the performances of UV PDs.