Stable field emission from hydrothermally grown ZnO nanotubes

Abstract

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 $7.0\mathrm{V}∕\mu \mathrm{m}$ at a current density of $0.1\mu \mathrm{A}∕{\mathrm{cm}}^2$ . Meanwhile, the emission current densities reached $1\mathrm{mA}∕{\mathrm{cm}}^2$ at a bias field of $17.8\mathrm{V}∕\mu \mathrm{m}$ . 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 $24\mathrm{h}$ test under a field of $15\mathrm{V}∕\mu \mathrm{m}$ .