Stable field emission from hydrothermally grown ZnO nanotubes

Zinc oxide nanotube arrays were prepared by hydrothermal reaction in ammonia and zinc chloride solutions, and the field emission properties were tested. The turn-on field of the field emission was extrapolated to be about 7.0 V/mu m at a current density of 0.1 mu A/cm(2). Meanwhile, the emission current densities reached 1 mA/cm(2) at a bias field of 17.8 V/mu m. The field enhancement factor beta was estimated to be 910. The field emission of the zinc oxide nanotubes showed good stability. The variation of emission current density was less than 10% during a 24 h test under a field of 15 V/mu m. (c) 2006 American Institute of Physics.