Field emission properties of zinc oxide/zinc tungstate (ZnO/ZnWO4) composite nanorods

Zinc oxide/zinc tungstate (ZnO/ZnWO4) nanorods were synthesized as composite nanostructure on the tungsten/glass substrates by thermal oxidation technique for field emission cathodes. The ZnWO4 wolframite structure in the ZnO film formed the ZnO/ZnWO4 composite nanostructure, as indicated by the XRD patterns and Raman spectrum. An ohmic contact was transformed to a Schottky contact between a silver electrode and the ZnO/ZnWO4 composite nanorods from I–V measurement given that the work function of the ZnO/ZnWO4 composite nanorods was lower than that of ZnO nanorods. The field emission properties of the ZnO/ZnWO4 composite nanorods includes a turn-on electric field (Eon) of 2.1 V/μm and a threshold electric field (Eth) of 2.9 V/μm, both much lower than that found in ZnO nanorods without ZnWO4 nanostructures. The novel ZnO/ZnWO4 composite nanorod shows excellent potential for application in field emission cathodes and related devices.

► The novel ZnO/ZnWO4 composite nanorods were synthesized.
► Between silver electrode and ZnO/ZnWO4 composite nanorods were formed a Schottky contact.
► The ZnO/ZnWO4 composite nanorods possess the lower work function than the ZnO nanorods.
► The lower work function of ZnO/ZnWO4 composite nanorods effectively enhanced the field emission properties.