Nanoparticle-Coated Silicon Nanowires

The synthesis of silicon nanowires that are densely coated with silicon nanoparticles is reported. These structures were produced in a two-step process, using a method known as hypersonic plasma particle deposition. In the first step, a Ti–Si nanoparticle film was deposited. In the second step the Ti-source was switched off, and nanoparticle-coated nanowires grew under the simultaneous action of Si vapor deposition and bombardment by Si nanoparticles. Total process time, including both steps, equaled 5 min, and resulted in formation of a dense network of randomly oriented nanowires covering1.5 cm2 of substrate area. The nanowires are composed of single-crystal Si. The diameters of the nanowires vary over the range 100–800 nm. Each nanowire has a crystalline TiSi2 catalyst particle, believed to have been solid during nanowire growth, at its tip.