Stacked silicon nanowires with improved field enhancement factor.

This work describes newly structured stacked silicon nanowires (s-SiNWs), consisting of nanosized silicon wires on top of silicon microrods (SiMRs) and exhibiting pronouncedly superior electron field emission (EFE) characteristics to the conventional SiNWs, by using a two-step electroless metal deposition process. Experimental results indicate that for these s-SiNWs, the electrostatic "screen effect" is markedly suppressed and the field enhancement factor (beta-value) is significantly increased ((beta)(s-SiNWs) = 2533). Additionally, the turn-on field (E(0)) for triggering the EFE process is reduced to a level comparable with that of carbon nanotubes, viz. (E(0))(s-SiNWs) = 2.0 V/mum. This simple and robust modified electroless metal deposition approach does not require either a high temperature or an expensive photolithographic process and possesses great potential for applications.