Field-emission from long SnO2 nanobelt arrays

We report on field emission from SnO2 nanobelt arrays with the length of about 90 mum grown on silicon substrates. The turn-on field of the nanobelt arrays at the current density of 1 muA/cm(2), is 4.5, 3.0, 2.4, and 2.3 V/mum as the distance between anode and cathode (d) is 0.1, 0.2, 0.35, and 0.5 mm, respectively. The current density rapidly reaches 2.1 mA/cm(2) at the electrical field of 4.4 V/mum at d=0.35 mm. The current density is higher than or comparable to those of the carbon nanotubes and other one-dimensional nanostructured materials. We also discuss the mechanism of high current densities and estimate the enhancement factor according to both the Fowler-Nordheim law and the reported model on micrometer-long of carbon nanotubes. (C) 2004 American Institute of Physics.