Temperature dependence of field emission from cupric oxide nanobelt films

Films of aligned cupric oxide nanobelts have been prepared in an aqueous solution at room temperature. Field-emission characteristics, including emission-current–applied-field plot and emission site distribution, have been studied using the transparent anode technique. In addition, the temperature dependence of the field-emission characteristics has been studied from room temperature to 750 K. The threshold field for obtaining a current density of 10 μA/cm2 is ∼11 MV/m. This decreases with increasing temperature, and at 700 K it is ∼6 MV/m. At a fixed field of 10 MV/m, about a three-orders-of-magnitude increase of the emission current level has been observed. The results show that the cupric oxide nanobelt is a promising candidate for cathode material in a thermoelectric conversion device based on field emission.