Enhanced Field Emission Properties in Gallium-Doped ZnO Nanowires through Simulation and Experiment

Field emission is a cornerstone phenomenon for advanced vacuum microelectronic devices, enabling next-generation applications. Achieving efficient, low-turn-on electron emission with a high field enhancement factor critically depends on the development of nanostructured materials with optimized morphology and electronic properties. In this study, we demonstrate how gallium (Ga) doping serves as an effective strategy to tune and boost the field emission characteristics of zinc oxide (ZnO) nanowire (NW) arrays. Ga-doped ZnO NWs with varying concentrations (0-4 at. %) were synthesized via a low-cost and facile combined two-step spin-coating and hydrothermal method and systematically characterized by complementary experimental analyses. The 2 at. % Ga-doped sample exhibited the most favorable performance, achieving the lowest turn-on (1.50 V/μm) and threshold (3.75 V/μm) fields and a significantly improved field enhancement factor (β = 8577). These improvements arise from the synergistic effects of increased electrical conductivity and optimized NW geometry at this ideal doping level. Finite element simulations further elucidated these findings by revealing how reduced NW diameter, improved alignment, and increased surface charge density (carrier concentration) associated with Ga doping collectively enhance the field enhancement factor. The computational results show excellent agreement with the experimental trends, confirming that controlled doping and structural optimization are key determinants of emission efficiency. This integrated experimental-theoretical simulation framework provides a mechanistic insight into the interplay between structural, electronic, and electrostatic factors and establishes Ga-doped ZnO NWs as a promising platform for high-performance field emission applications.