The nano-zinc oxides (ZnO) synthesized by thermal evaporation of zinc powder with silver powder at different temperature and zinc powder only were compared. Scanning electron microscopy (SEM) was applied to study the morphologies and X-ray diffraction (XRD) was exerted to characterize the crystal structure. The field emission cathode was fabricated with a simple screen printing method. We packed the cathode panel and the anode panel printed with phosphor power as a field emission display with diode structure for the contrastive field emission experiment. The results show that the higher synthesizing temperature of the sample

the better field emission;the sample synthesized by the evaporation source including zinc powder and silver powder shows better field emission than that for the single source only including zinc powder. It’s shown from the experimental results that nano-ZnO semiconductor material is a good candidate for a field emission cathode and has potential application in vacuum electronics.