Ultraviolet photodetector based on Au doped TiO₂ nanowires array with low dark current

Abstract

Au nanoparticles doped TiO₂ nanowires (NWs) arrays with an average diameter of 100 nm were synthesized through a facile solvothermal method. Thereafter, metal/semiconductor/metal (MSM) structured detectors with Ag electrodes were fabricated on these NWs. The ultraviolet (UV) sensing characteristics of pure TiO₂ and Au-doped ones (Au-TiO₂) were investigated. Compared with pure TiO₂, the Au-TiO₂ NWs based device shows a much lower dark current of 1.5 nA at 3 V bias. The low dark current mechanism might be due to the promoted directional transmission of carriers induced by Au doping. The photoresponse is nearly one order of magnitude under 360 nm monochromatic illumination. The Au-TiO₂ NWs detector with simple fabrication process, low noise and good overall performance provides a broad way in fabricating UV imaging arrays.