Preparation and investigation of nano-thick FTO/Ag/FTO multilayer transparent electrodes with high figure of merit

Abstract

In order to improve the conductivity of the single-layered nano-thick F doped SnO2 (FTO) thin films, an Ag mid-layer is embedded between the FTO layers. In our work, the effects of mid-layer Ag and top FTO layer on the structural, electrical and optical properties of FTO/Ag/FTO multilayered composite structures deposited on quartz glass substrates by magnetron sputtering at 100 °C have been investigated. As the thickness of Ag mid-layer increases, the resistivity decreases. As the top FTO layer thickness increases, the resistivity increases. The highest value of figure of merit φTC is 7.8 × 10-2Ω-1 for the FTO (20 nm)/Ag (7 nm)/FTO (30 nm) multilayers, while the average optical transmittance is 95.5% in the visible range of wavelengths and the resistivity is 8.8 × 10-5Ω·cm. In addition, we also describe the influence of Ag and top FTO layer thickness on structural, electrical and optical properties of the nano-thick FTO (20 nm)/Ag/FTO multilayers and the mechanism of the changes of electrical and optical properties at different Ag and top FTO layer thicknesses.