Establishing a gold nanoparticle quasi-mesh structure in Al-doped zinc oxide film to enhance photoelectric properties

Abstract A low-cost chemical reduction method was applied to reduced gold nanoparticles (Au-NPs), which were used in aluminum-doped zinc oxide (Al:ZnO, AZO) film deposited using a magnetron sputtering system. The Au-NPs were mixed under different process parameters to effectively remove organic matter on the Au-NPs and form a three-dimensional quasimesh structure of Au to improve the photoelectric properties of the AZO film. Different levels of sputtering power were applied to prepare a high-quality AZO seed layer, sintering temperature and rotating speed in spin coating were adjusted to improve the effect of Au-NPs on the photoelectric properties of the AZO film. Transmission electron microscope, scanning electron microscope, and X-ray diffractometer were used to analyze the structure and distribution of the Au-NPs, and also crystal characteristics of the AZO film. An ultraviolet–visible–near infrared spectrophotometer and a Hall effect measurement system were implemented to measure the photoelectric properties of the film. According to the results, a quasi-mesh structure with the optimal Au-NPs distribution was established by depositing the AZO seed layer with 150 W of sputtering power, processing it with thermal annealing at 500 °C, spin coating the Au-NPs on the textured surface of the AZO film at 3000 rpm, and sintering the film at 800 °C for 10 min. This structure reduced film resistance to 3.57 × 10−3 Ω-cm, and a maximal transmittance of 84.15% within the visible spectrum, and resulted in a figure of merit of 3.99 × 10−4 Ω−1.