Strategies to Improve Field Emission Performance of Nanostructural ZnO

Nanostructural ZnO is a good candidate for field emission (FE) because of its high aspect ratio, controllable electrical conductivity, and good thermal and chemical stability. In order to improve the FE performance, ZnO nanopins, gallium-doped nanofibers, periodic nanorod arrays, and aligned nanotubes were designed and fabricated by a vapor-phase transport method using ZnO + C and ZnO + C + Ga₂O₃ powder mixtures, electrochemical deposition, and hydrothermal decomposition, respectively. The FE behaviors including threshold of electric field, emission current density, field enhancement factor, and stability are reviewed in this paper based on our previous works. Some strategies to improve the performance of the nanostructural ZnO field emitters are demonstrated.