Enhanced field emission from injector-like ZnO nanostructures with minimized screening effect.

Injector-like zinc oxide (ZnO) nanostructures have been synthesized on Si substrate by the vapour phase transport method. Samples with different areal densities were obtained by controlling the temperature. The field emission properties of the injector-like ZnO nanostructures showed a clear dependence on the areal density of the nanostructures, which is due to the screening effect. The samples with a needle length of 850 nm and an areal density of 1 × 10(8) cm(-2) showed the lowest field emission turn-on field of 1.85 V µm(-1) at a current density of 10 µA cm(-2), and the current density reaches 1 mA cm(-2) at an applied field of 4.7 V µm(-1).