Diameter controlled fabrication of ultralong silicon wires through regulating metal mass in massive metal-assisted chemical vapor deposition

The successful fabrication of ultra-long silicon wires has facilitated the study and application of silicon wires. However, research on the controlled fabrication of ultralong silicon wires, such as diameter modulation, is still insufficient. Herein, tapering ultralong silicon wires are synthesized by using a massive metal-assisted chemical vapor deposition method. By altering the mass of the tin catalyst in the growth zone, the length and changing rate of the diameter can be modulated. When a 40 g catalyst is placed in the growth region, the length of obtained silicon wires is 6.6 mm, and the changing rate of diameter with length is 541 nm/mm. When the catalyst mass in the growth region is reduced to 20 g, the length of the products decreases to 4.0 mm, and the changing rate of diameter with length increases to 964 nm/mm. This work proposes a new route for the diameter-modulated fabrication of ultralong silicon wires and will promote their application across various fields.