Efficient field emission from tetrapod-like zinc oxide nanoneedles

Tetrapod-like zinc oxide (ZnO) nanoneedles were fabricated using a simple and economical method of rapid heating high purity zinc powders at 900 °C. No catalyst and vacuum were employed in the experiment. Field-emission measurements showed that the turn-on field of the synthesized tetrapod-like ZnO nanoneedles was as low as 1.8 V/μm at the emission current density of 1.0 μA/cm2 and the emission current density reached 1.0 mA/cm2 under an applied field of about 3.9 V/μm. The low turn-on field, high emission current density, and good electron emission stability make the ZnO nanoneedles one of the promising candidates for field-emission displays.