Investigation of the temperature dependence of the field emission of ZnO nanorods

Temperature-dependent field emission characteristics of ZnO nanorods are reported in this study. The work function of ZnO nanorods is notably reduced with the temperature increasing from 100 to 600 K. The electron emission properties of ZnO nanorods are very sensitive to temperature. The turn-on field decreases significantly from 7.5 to 1.9 V mu m(-1), while the emission current increases remarkably with the increasing temperature. Moreover, the real-time images ( recorded by CCD camera) of field emission from ZnO nanorods support the above I - V results. The strongly thermo-enhanced emission of ZnO nanorods suggests that the increasing temperature could significantly excite the electrons on the defect-dependent donor levels into a vacuum through a narrowed tunnel by an applied electric field.