Field emission and photofluorescent characteristics of zinc oxide nanowires synthesized by a metal catalyzed vapor-liquid-solid process

The ZnO nanowires synthesized by vapor-liquid-solid growth mechanism with Cu and Au as the catalyst were investigated. The principal differences in morphology between Cu and Au catalyzed ZnO nanowires are observed and lead to significant differences in their field emission and photofluorescent characteristics. The Cu catalyzed ZnO nanowires with a high-quality wurtzite structure were grown vertically on p-type Si(100) substrate along [0002] direction. A strong ultraviolet emission at 381 nm is observed. These ZnO nanowires show excellent field emission properties with turn-on field of 0.83 V/μm and corresponding current density of 25 μA/cm2. The emitted current density of the ZnO nanowires is 1.52 mA/cm2 at a bias field of 8.5 V/μm. The large field emission area factor, β arising from the morphology of the nanowire field emitter, is partly responsible for the good emission characteristics. The ZnO nanowires with high emission current density and low turn-on field are expected to be used in field emission flat panel display.