Tunable UV response and high performance of zinc stannate nanoparticle film photodetectors

High-performance photodetectors are costly due to either the expensive nature of active materials or sophistication in the fabrication process required to meet performance targets. In this work, low-cost metal stannate based nanostructures are demonstrated as active materials for high-performance UV photodetectors. A robust, inexpensive, and scalable drop-casting process was successfully developed to fabricate thin film devices composed of amorphous ZnSnO3 nanocubes and/or polycrystalline Zn2SnO4-SnO2 nanoparticles with different optical and electronic structures. Moreover, the Zn2SnO4-SnO2 heterojunction nanoparticles were directly obtained by thermal treatment of amorphous ZnSnO3 nanocubes. Large-area, uniform, and continuous film photodetectors were achieved with pronounced and fast response upon exposure to UV illumination (lambda < 370 nm), showing both rise and decay times less than 1.0 s. More advantages based on these two stannate nanostructures were observed compared with their counterparts, such as ZnO, SnO2, Zn2SnO4, ZnO-SnO2 individual nanostructures or film photosensors, including high photo-sensitivities (S > 10(2) and similar to 10(3) was achieved for ZnSnO3 and Zn2SnO4-SnO2 photodetectors, respectively) and excellent responsivity (as high as 0.5 A W-1 at 5.0 V bias from the Zn2SnO4-SnO2 photosensors) under low light intensity. This work provides a simple, cost-effective and tunable processing strategy to synthesize and apply earth-abundant metal stannate based nanomaterials for high performance UV photodetectors and other optoelectronic devices.