Aligned ultralong ZnO nanobelts with an average length of 3.3 mm and widths up to 6 mu m (see figure) are synthesized on a metal substrate through a one-step process. The nanobelts obtained from this molten-salt-assisted thermal evaporation route show an emission current density of 1 mA cm(-2) at an electric field of 2.9 V mu m(-1) resulting from their high field-enhancement factor (1.4 x 10(4)).