Tuning the strain and physical properties of highly epitaxial CaCu3Ti4O12 thin films on vicinal substrates

Abstract

Epitaxial thin films of perovskite-like structural CaCu3Ti4O12 (CCTO) were grown on vicinal (001) single-crystal LaAlCb (LAO) substrates to investigate the evolution of micro structure and dielectric properties of the films with the mismatch strain induced by surface step terrace. The different surface terrace width of the substrates produced by various miscut angles of 1.0°, 2.5°, and 5.0° along [110] direction successfully tuned the lattice structure, which were confirmed by X-ray diffraction. A model is proposed that the substrate step terrace dimensions on each vicinal LAO substrate can be tuned by miscutting angles, which introduces compressive and tensile strained domains of the CCTO film and further affect the dielectric properties. Based on this growth mode, we can achieve high dielectric constant and reduce the dielectric loss by a proper design of the miscutting angles.