Efficient field emission characteristics from a planar-gate surface-conduction electron source with ZnO emitters

•The planar-gate surface-conduction electron source has been fabricated.•ZnO nanorods deposited on the cathode are used as field emission emitters.•ZnO nanorods deposited in the C–G gap are used as surface conduction emitters.•High electron emission efficiency is obtained at low gate voltage.•The fabricated electron source has an efficient field emission property. A planar-gate surface-conduction electron source with ZnO nanorods has been successfully fabricated, where ZnO nanorods deposited on the cathode are used as field emission emitters and ZnO nanorods deposited in the gap between cathode and gate electrode (C–G gap) are used as surface-conduction emitters. Field emission investigations indicate that the turn-on voltage at emission current of 10μA is approximately 85V. The emission current and conduction current reach to 520V and 450V at the gate voltage and anode voltage of 140V and 2000V, respectively. High electron emission efficiency (56.2%) is obtained at low gate voltage of 140V. The maximum brightness can reach 1200cd/m2 and the emission current fluctuation is smaller than 5% for 6h. These results indicate that the electron source based on the planar-gate surface-conduction triode with ZnO emitters has efficient field emission characteristics.