TiO2 embedded Si nanowire network based Schottky detector for enlarged light detection.

Abstract

The Si nanowire (NW) network was fabricated on the Si substrate with the help of glancing angle synthesized Ag NPs assisted etching technique. The horizontal Si NWs network was characterized by field emission gun-scanning electron microscopy which shows the formation of long Si NWs of diameter within the range of 110-180 nm. The TiO2 thin film (TF) was deposited on the Si NWs, which shows -2.5 times enlarged optical absorption than that of bare Si substrate. Ag-TiO2 contacts exhibit Schottky behaviour and higher photoconduction was observed for TiO2-Si NW detector than that of TiO2 TF under illumination. The dark currents of TiO2 TF and TiO2-Si NW devices were exerted to be 0.1 mA/cm2 and 0.2 mA/cm2 at +1 V, which increased to 0.2 mA/cm2 and 1.23 mA/cm2, respectively, under the illumination of 100 W filament bulb. A threefold enhanced photodetection for the Si NW device was observed compared to the TiO2 TF device. The nonlinear rise of photocurrent of 2 x 10(-2) mA/cm2, after 5 min light illumination was observed due to carrier diffusion effect.