Highly Efficient Visible-Blind Ultraviolet Photodetector Based on Scalably Produced Titanium Dioxide Nanowire Arrays

Here, we report a novel, feasible, and cost-effective method for the preparation of one-dimensional TiO₂ nanowire arrays using a super-aligned carbon nanotube film as a template. Pure-anatase-phase TiO₂ nanowires were scalably prepared in a suspended manner, and a high-performance ultraviolet (UV) photodetector was realized on a flexible substrate. The large surface area and one-dimensional nanostructure of the TiO₂ nanowire array led to a high detectivity (1.35 × 10¹⁶ Jones) and an ultrahigh photo gain (2.6 × 10⁴), respectively. A high photoresponsivity of 7.7 × 10³ A/W was achieved under 7 μW/cm² UV (λ = 365 nm) illumination at a 10 V bias voltage, which is much higher than those of commercial UV photodetectors. Additionally, by taking advantage of its anisotropic geometry, we found the TiO₂ nanowire array showed polarized photodetection. The concept of using nanomaterial systems shows the potential for realization of nanostructured photodetectors for practical applications.