Electrochemical preparation of silicon nanowires from porous Ni/SiO2 blocks in molten CaCl2

Abstract

Silicon nanowires (SiNWs) with diameter distributions ranging from 80 to 350 nm were prepared by electrochemical reduction of Ni/SiO2 in molten CaCl2. The effect of the content of nickel additives on the morphology of produced silicon was investigated. Large quantities of SiNWs are obtained by the electrochemical reduction of Ni/SiO2 blocks with SiO2 to Ni molar ratio of 20 and 10. Nickel additives repress the growth of irregular branches and promote longitudinal growth of SiNWs. Wire morphologies and surfaces are influenced by the electrolysis temperature. SiNWs become thicker with the increase of the electrolysis temperature. The optimum temperature to prepare single crystal SiNWs with high aspect ratio and extraordinary surface quality seems to be 1173 K. The amorphous layer of the silicon nanowire is thinner compared to the SiNWs obtained from the pure SiO2 pellets. The produced SiNWs show a photoluminescence emission peak at about 758 nm at room temperature. This work demonstrates the potentiality for the electrochemical reduction process to obtain large quantities of SiNWs with high quality. Silicon nanowires (SiNWs) were prepared by the electrochemical reduction of Ni/SiO2 blocks in molten CaCl2. The effects of the content of nickel additives and the electrolysis temperature on the morphology of produced silicon were investigated. Nickel additives promote the oriented growth of SiNWs and the SiNWs become thicker with the increase of electrolysis temperature.