Gate-controlled ZnO nanowires for field-emission device application

Abstract

Gate-controlled field-emission devices have great promise for a number of applications such as bright electron source or flat display array. The gate-controlled ZnO nanowire (NW) field-emission device was fabricated using lift-off fabrication process to synthesize side-gate control in the present investigation. This device effectively controls the turn-on electron beams and switches the drain current (Id) under a threshold gate voltage (V-T) of similar to 35 V. In the meantime, the current density of the device is similar to 1 mA/cm(2) that is similar to carbon nanotube (CNT) field-emission level with a potential for the design of field-emission display (FED) devices. Furthermore, when the gate voltage (V-g) is equal to 0 V, the turn-on electric field (E-to) for ZnO NWs is similar to 0.8 V/mu m and the effective-field-enhancement factor 8 is similar to 7000. As Vg is increased to 10, 20, 30, and 40 V, the E, lowers to the range of -0.8-0.6 V/mu m and the 8 value increases to similar to 7600-17 800. The continuous increases in V,, lowers the turn-on electric field because the local electric field (E-local) generated induces an extra force that enhances electron emission from the ZnO NWs. Besides, the transconductance (g) value can approach 0.388 mS while the V-g is increased to 44.5 V. The devices have well-controlled behavior and exhibit better Fowler-Nordheim characteristic in comparison with classic CNT field-emission devices. The gated ZnO NW array has a good opportunity to be applied to FED devices and be integrated to the semiconductor industry in the future. (c) 2006 American Vacuum Society.