Photoconductivity of Au-coated TiO2 nanotube arrays

In this paper, we report fabrication and photoconductive properties of Au-doped titanium nanotube (TNT) arrays. Scanning electron microscope with energy dispersive x-ray spectroscopy (SEM-EDX) indicates that diameter of as-prepared TNT is distributed from 80 to 160 nm. The as-prepared TNTs show an amorphous structure and completely converted into anatase phase after annealing at 450°C for 3 hours. A sandwich-type (Indium tin oxide glass/TNT or Au-doped/Ti) device was assembled for photoelectric characterization. Photocurrent of Au-doped TNT arrays is increased to 28.7 mA at applied voltage of 1 V under ultra-violet radiation as compared with that of pristine TNT device (0.7 mA). A phenomenal sketch is given to understand enhancement of the photoconductivity.