Characterization of Au Nanoparticles Adsorbed on 1-D ZnO Nanomaterials Through a Novel Photochemical Synthesis Way for Field- Emission Emitter Applications

This work explores the growth of vertically aligned zinc oxide nanorod (ZnO NR) arrays on a conductive indium-tin-oxide (ITO) substrate by using a simple hydrothermal solution route method at 95 °C for 3 h. Additionally, the gold nanoparticles (Au NPs) were victoriously adsorbed on the NR surface through a low-cost photochemical method under ultraviolet (UV) light at room temperature for field-emission (FE) emitters. To explore one-dimensional (1-D) nanostructures, high-resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD), and field-emission scanning electron microscope (FE-SEM) measurement were conducted. It was found that the NRs were almost perpendicular to the substrate with c-axis direction. The Au concentration of the 1-D NR array was 0.75 at% in energy-dispersive X-ray (EDX) result. ZnO nanomaterials with and without Au NPs were labelled 1-D Z@Au-3 and Z@Au-0 NRs, respectively. The turn-on electric field and effective field enhancement factor (β) of the Z@Au-0 NR devices were 4.56 V/μm and 4902, and those of the Z@Au-3 NR devices were 3.25 V/μm and 12955, respectively. Meanwhile, the slope value of the Z@Au-3 sample (6.43) was also lower than that of the Z@Au-0 NR sample (17.01). It can be seen that the Au NPs enhanced the FE property of the emitter. As a result, the designed 1-D ZnO samples with noble Au NPs are an encouraging candidate in future FE-based device applications, which can use in various electronic applications such as FE display panels, X-ray sources, light sources, and parallel electron beam microscopes.