P-cu 2o-shell/n-tio 2-nanowire-core heterostucture photodiodes

Abstract

This study reports the deposition of cuprous oxide [Cu 2O] onto titanium dioxide [TiO 2] nanowires [NWs] prepared on TiO 2/glass templates. The average length and average diameter of these thermally oxidized and evaporated TiO 2 NWs are 0.1 to 0.4 μm and 30 to 100 nm, respectively. The deposited Cu 2O fills gaps between the TiO 2 NWs with good step coverage to form nanoshells surrounding the TiO 2 cores. The p-Cu 2O/n-TiO 2 NW heterostructure exhibits a rectifying behavior with a sharp turn-on at approximately 0.9 V. Furthermore, the fabricated p-Cu 2O-shell/n-TiO 2-nanowire-core photodiodes exhibit reasonably large photocurrent-to-dark-current contrast ratios and fast responses. © 2011 Tsai et al.