Aligned 1D silicon nanostructure arrays by plasma etching

High-density aligned arrays made of one-dimensional (1D) silicon nanostructures, including nanocone, nanorod, and nanowire, are fabricated by plasma etching in a hot-filament chemical vapor deposition apparatus using the gas mixture of hydrogen, nitrogen and methane. The silicon nanocones are crystalline structure and have a uniform apex angle of about 22°. The cones can be coated in situ with an about 3 nm thick amorphous carbon film by increasing the methane concentration in source gases. With gradually decreasing the plasma intensity, the morphologies of the silicon nanostructures evolve along the nanocone–nanorod–nanowire route, and the nanowire becomes amorphous structure. The model for fabrication process of silicon nanostructures with different morphologies will also be suggested.