Field emission from various CuO nanostructures

Abstract

Three types of CuO nanostructures—the nanorod, nanofiber, and nanoparticle—have been grown by using a self-catalytic growth process at 400, 500, and 600 °C, respectively. Field-emission (FE) properties of the CuO nanostructures were investigated. The results indicated that the FE current was significantly affected by the morphologies of the CuO samples. Typical turn-on voltage for the CuO nanofiber array was detected at about 6–7 V/μm with an emission area of 1 mm2. Based on Fowler–Nordheim plot, the values of work function for the nanofiber array were estimated in ranges of 0.56 to 2.62 and 0.30 to 1.39 eV from a two-stage linearity plot. X-ray photoelectron spectroscopy analysis showed no obvious changes in chemical composition of the nanofiber array before and after FE tests. According to the analyses, the highly ordered CuO nanofiber array can be a promising candidate for FE emitters.