Fabrication of Single Si Nanowire Metal–Semiconductor–Metal Device for Photodetection

The photoresponse of a metal-semiconductor-metal (MSM) device using single silicon nanowire (Si NW) (~50-nm diameter) with responsivity approaching 3 A/W and external quantum efficiency ~900% at a moderate bias of 1.0 V is reported. The device exhibits a rapid switching of the current when the light of wavelength 405 nm is turned ON/OFF even at zero bias. The dark and illuminated current-voltage characteristics are studied using the MSM device model. The analysis indicates that a dominant contribution to the photoresponse arises from the reduction of the barrier at the contact regions along with photoconductive response in the strand of the Si NW.