Stable Heating Above 900 K in the Field Emission of ZnO Nanowires: Mechanism for Achieving High Current in Large Scale Field Emitter Arrays

Abstract The thermal runaway of a quasi‐1D (Q1D) field emitter is an important cause of vacuum breakdown, which limits the field emission current density in field emitter arrays (FEAs). Comprehensive knowledge on the self‐heating process of zinc oxide (ZnO) nanowires is important for obtaining a high breakdown field for activating more emitters. This work investigates the self‐heating model of individual ZnO nanowire by considering the thermal field emission current distribution along the nanowire. Theoretical calculations suggest that the thermal field emission distribution along the nanowire can be reflected on the profile of the field emission pattern, which offers a method for determining its temperature. The field emission ring pattern is experimentally observed in the ZnO nanowire, whose intensity profile indicates that the nanowire can be steadily heated above 900 K. Considering the high breakdown field of high‐thermal stability ZnO nanowires, the field emission current density of ≈1.4 mA cm⁻² can be achieved using these nanowires in a 3.5‐inch FEA. These findings provide an alternative method for measuring the Q1D field emitter temperature and a guideline for improving the field emission current from large‐scale Q1D FEAs.