Formation of Si nanowires by the electrochemical reduction of porous Ni/SiO2 blocks in molten CaCl2

Abstract

Silicon nanowires (SiNWs) were prepared by the electrochemical reduction of solid Ni/SiO2 blocks in molten CaCl2 at 1173K. The SiNWs have diameter distributions ranging from 80 to 350nm, and the nickel–silicon droplets are found on the tips of the nanowires. The growth mechanism of SiNWs was investigated, which confirmed that the nano-sized nickel–silicon droplets formed at the Ni/SiO2/CaCl2 three-phase interline. The droplets lead to the oriented growth of SiNWs. Formation of nano-sized nickel–silicon droplets suggests that this method could be a potential way to produce nano-sized metal silicides.