Synthesis and efficient field emission of ZnO nanoinjectors

ZnO nanoinjectors were synthesized on Au-coated Si substrate by direct thermal evaporation of zinc powder at a low temperature of 600 °C and atmospheric pressure. Field-emission scanning electron microscopy and X-ray diffraction were applied to study the structural characteristics of the sample. The result indicated that the nanoinjector sample consisted of single-crystalline wurtzite structures which were preferentially oriented in the 〈0 0 1〉 direction. The field emission of the sample started at a turn-on field of 1.5 V/μm at a current density of 1 μA/cm2, while the emission current density reached about 1 mA/cm2 at an applied field of 5.0 V/μm.