Efficient field emission from ZnO nanoneedle arrays

Well-aligned arrays of ZnO nanoneedles were fabricated using a simple vapor phase growth. The diameters of the nanoneedle tips are as small as several nanometers, which is highly in favor of the field emission. Field-emission measurements using the nanoneedle arrays as cathode showed emission current density as high as 2.4 mA/cm(2) under the field of 7 V/mum, and a very low turn-on field of 2.4 V/mum. Such a high emission current density is attributed to the high aspect ratio of the nanoneedles. The high emission current density, high stability, and low turn-on field make the ZnO nanoneedle arrays one of the promising candidates for field-emission displays. (C) 2003 American Institute of Physics.