Widely transparent electrodes based on ultrathin metals

Abstract

Transparent electrodes made of single-component ultrathin $(<10\mathrm{nm})$ metal films (UTMFs) are obtained by sputtering deposition. We show that the optical transparency of the deposited films (chromium and nickel) is comparable to that of indium tin oxide (ITO) in the visible and near-infrared range $(0.4–2.5\mu \mathrm{m})$, while it can be significantly higher in the ultraviolet $(175–400\mathrm{nm})$ and mid-infrared $(2.5–25\mu \mathrm{m})$ regions. Despite their very small thickness, the deposited UTMFs are also uniform and continuous over the $10\mathrm{cm}$ substrate, as it is confirmed by the measured low electrical resistivity. The excellent optical and electrical properties, stability, compatibility with active materials, process simplicity, and potential low cost make UTMFs high-quality transparent electrodes for the optoelectronics industry, seriously competing with widely used transparent conductive oxides, such as ITO.