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.