Dye-Improved Optical Absorption of Vertically Aligned Silicon Nanowire Arrays Synthesized by Electroless Etching of Silicon Wafer

Abstract

Silicon nanowires (SiNWs) are important candidate for high performance electronic and optoelectronic devices due to their unique structures, electrical and optical properties. SiNWs were fabricated by silver-assisted electroless etching of Si wafer. Vertically aligned SiNW arrays with length about 8.75 μm and diameter of less than 90 nm have been fabricated. The reflectance of SiNWs without dye (12%) is greatly lower compared to bare Si wafer (25%). Therefore, SiNWs on Si substrate can be used as a good anti-reflection layer for a wide range of incident light. The reflectance of dye-sensitized SiNWs with red, green and blue dyes is 7%, 5.5%, and 5% respectively. The results confirmed that the reflectance of SiNWs with dye is much lower compared to SiNWs without dye and bare Si wafer. It was proven that dye on SiNWs can be used to reduce the reflectance (improved absorption) about 40% compared to SiNWs without dye.