Low-E glass improvement by the understanding and control of the Ag growth

Ag thin films are widely used in Low-E glass. High conductivity and low emissivity require a film thickness of at least 10 nm, which is costly for the industry. The cost of Low-E coating could be drastically reduced by lowering the amount of Ag without decreasing the conductivity. For that purpose, it is necessary to understand Ag film growth and related macroscopic properties. This can be studied by thin film growth simulations. In this work, we present results of Ag growth on ZnO by magnetron sputtering and related properties with multiscale simulations (DFT, Molecular Dynamics, and kinetic Monte Carlo). A new method to take into account defects generated by magnetron sputtering has been developed. Simulated conductivity has been compared with experiments and shows the same trend with a difference attributed to electron scattering at grain boundaries. To go further, we propose patterned substrates with and without defects to find an original tuneable process to increase the conductivity of ultrathin metallic films. We show that a patterned substrate does not increase the conductivity. Instead, it leads to a controlled growth of small islands which could be used for other applications requiring plasmonic properties. Finally, conductivity is higher for the same deposited thickness when the substrate has a higher defect density.