Fig. 6

Schematic illustration of α-SiNW growth. During the annealing process, Cu patterns (a) dewet to the center of the pattern (b), and react with SiO₂ to form Cu silicide (c). Then, Si atoms permeate into the Cu silicide. During this process, the different diffusion speed of Si atoms in the substrate which caused by the defect of substrate may induce the Si gap formation. When the dissolving Si atoms in silicide reached saturation, Si starts to precipitate to synthesis α-SiNWs (d)