Field emission properties of silicon nanowires

Silicon nanowires were suggested as a material in production of field emission spot like cathodes. Field emission properties of high purity silicon nanowires produced by method of melt´s electrolysis of the mixture KCl-KF-K₂SiF₆-SiO₂ were investigated. The diameters dispersion of nanowires under consideration were approximately from 10 nm to 100 nm. Nanowires originally produced as “wisp” on carbon substrate firstly were separated from substrate then were reduced to fragments and further were strengthened to tungsten cathode in a shape of spike with curvature radius approximately 0.1-1 mcm by organic binder which was evaporated in a vacuum immediately before measurements. The volt- ampere characteristics the cathodes patterns were measured for voltages from 0,5 kV to 1,5 kV. The maximum achieved stable work current was 5 μA for a voltage 3.95 kV. The threshold current leading to dramatic destruction of the wires was estimated by 10 μA. As soon as this threshold had been reached spark discharge occurred and thin film of Si on tungsten tip formed in some experiments. In this case field emission became stable up to 25 μA and started with emission voltages of 300 V. The energy distributions of emitted electrons was obtained for silicon nanowires and nanoparticles of Si on tungsten tip.