Apart from improving the field emission efficiency by optimizing the aspect ratio (length/diameter) of 1D nanostructures, other methods were also used to enhance the field emission current. Wang and Li found that laser irradiation could effectively improve the field emission current of CuO nanowire arrays. The effects of laser intensity, wavelength, emission current, and working vacuum on the enhancement have been investigated in detail. Among these factors, the contribution from extra excited electrons, which increases the number of electrons in the conduction band of CuO for subsequent tunneling, is dominant. The observed laser-induced enhancement in field emission current is attributed to the interplay of two factors: laser-induced electron transition to excited states and surface oxygen desorption. Based on the idea of light-induced field emission of their work, new vacuum nanodevices of CuO nanowires, such as photodetectors or switches, could be developed in the future.
Another example is the work of Maji et al. Where the authors also prepared CuO nanowire arrays by thermal oxidation. To improve the field emission properties of CuO nanowires, they coated a ZnO layer on a Cu substrate before the thermal oxidation process. The ZnO layer was deposited by immersing a Cu foil into an aqueous zinc nitrate and hexamethylenetetramine solution at 95°C for several hours. The turn-on field of the ZnO-coated CuO nanowire array was 0.85 V/μm compared with the turn-on field of 6.5 V/μm of CuO nanowires without ZnO coating layer at the same current density of 10 μA/cm2. The authors suggested that crack elimination may be the reason for enhancing field emission properties in addition to the enlarged nanowire density and aspect ratio. If you are looking for high quality, high purity, and cost-effective copper oxide, or if you require the latest price, please email contact mis-asia.
