LAUSR

UV (ultraviolet) photodetectors with high performance have a wide range of applications such as environmental monitoring and water sterilization. Herein, we have demonstrated that the visible-blind UV photodetectors based on polycrystalline SnO2 nanotubes by electrospinning combined the advantages of low dark current and high photocurrent-to-dark current ratio. The optimized photodetector based on SnO2 nanotube film showed a strong rise in current amplitude; the photocurrent was 25.60 nA, about 850 times larger than the dark current of 0.03 nA, under a voltage as small as 1.0 V and 320 nm illumination at 75 μW/cm2. In addition, these devices presented improved characteristic on time responses. Investigations indicated that the features of high signal-to-noise ratio and relatively fast response speed are strongly relied upon the band-edge modulation along the axial direction of nanotube, where Schottky barriers are formed among the grain interfaces of polycrystalline SnO2 nanoparticles, together with the processes of oxygen adsorption/desorption in air. These results suggest that the polycrystalline SnO2 nanotube is a potential candidate for the fabrication of photodetector with low cost and high performance.