ZnO nanoneedles with tip surface perturbations: Excellent field emitters

The synthesis of ZnO nanoneedles with multiple tip surface perturbations through chemical vapor deposition was discussed. The nanoneedles were prepared on a silicon wafer and were characterized by high-resolution transmission electron microscopy. It was observed from the field-emission measurements on the sample nanoneedles that nanoneedles exhibited low turn-on and threshold fields of 2.5 and 4.0 V/μm, respectively. It was also observed that the multiple tip surface pertubations of the nanoneedles had accounted for its field-emission properties.