Fabrication and properties of planar gate field emission arrays with patterned ZnO nanowires

Field emission arrays (FEAs) based on a planar gate triode with patterned ZnO nanowires have been successfully fabricated by conventional photolithography, screen printing and thermal evaporation. ZnO nanowires were synthesised on the cathode and the gap between cathode and gate electrodes (C-G gap). The SEM images show that the diameters of ZnO nanowires are scattered in a range of 80-200 nm and the length up to 5 mm. Field emission investigations indicate that the turn-on voltage of 875 V at emission current density of 1 mu A cm(-2) in the triode mode is lower than that of 1575 V in the diode mode. In triode mode, the anode current and gate current come to 330 and 320 mu A at the gate voltage and anode voltage of 300 and 1000 V respectively and at the anode-cathode spacing of 500 mu m, which indicates that the triode mode based on planar gate FEAs with patterned ZnO nanowires has efficient field emission characteristics.