Residual stress-dependent electric conductivity of sputtered co-doped CeO2 thin-film electrolyte

Abstract

Sm3+ and Nd3+ co-doped ceria thin-film electrolytes have been deposited on polycrystalline alumina substrates via RF magnetron sputtering. Electric conductivity is evaluated with respect to the residual stress in the film by sin2 ψ-methodology, indicating that an in-plane tensile stress is applied to the as-deposited film. The stress in the film increases as annealing temperature decreases, and there is an enlarged crystal lattice. The results also reveal that the annealed film with a greater stress shows a higher electric conductivity, which might be due to the lower activation energy. The conductivity of the film annealed at 600 °C is as high as 0.009 S cm−1 at 500 °C, and the residual stress is determined to be 542.70 MPa at room temperature.