Domain Control and Periodic Poling of Epitaxial ScAlN

ScAlN is an emerging ferroelectric material that possesses large bandgap and strong piezoelectricity and holds great promises for enhanced χ(2) nonlinearity. In this study, we demonstrate high-fidelity ferroelectric domain switching and periodic poling of Al-polar ScAlN thin film epitaxially grown on a c-axis sapphire substrate using gallium nitride as a buffer layer. Uniform poling of ScAlN with periods ranging from 2 to 0.4 μm is realized. The ability to lithographically control the polarization of epitaxial ScAlN presents a critical advance for its further exploitation in ferroelectric storage and nonlinear optics applications.