Visible and ultraviolet light alternative photodetector based on ZnO nanowire/n-Si heterojunction

Closely packed ZnO nanowire array was fabricated on a n-type Si (100) substrate by a magnetron cosputtering method. The ZnO nanowire/n-Si heterojunction showed good diode characteristics with rectification ratio of above 1.6×102 at 4V in the dark. Experiments demonstrated that the diode could be used to detect either visible or ultraviolet light by easily controlling the polarity of the voltage applied on the heterojunction. The spectral response of the device will be discussed in terms of the band diagrams of the heterojunction and the carrier diffusion process.