Enhanced field emission from ZnO nanowires grown on a silicon nanoporous pillar array

A large scale heterostructure array of ZnO nanowires/silicon nanoporous pillar array (Si-NPA) is prepared by a self-catalytic thermal evaporation and vapor-phase transport method and an ultrahigh field emission current density is obtained with a low turn-on field. The studies have shown that ZnO/Si-NPA is an ideal candidate cathode of potential applications in flat panel displays and high brightness electron sources.