MBE-grown BaTiO₃ films for waste heat energy conversion using first order phase transformation

A new method for heat to electricity conversion which takes advantage of the first order phase transformation of ferroelectric materials will be presented. Low temperature waste heat can be utilized with the proposed device in which a transfer of energy was successfully shown using a BaTiO₃ single crystal heated and cooled repeatedly through its phase transformation. [1] We use these results as a motivation for our discussion on the growth of ferroelectric thin films using the hybrid molecular beam epitaxy approach. High quality, epitaxial single crystal BaTiO₃ thin films were grown using this technique and showed a bulk-like phase transformation with thickness of 350 nm, an encouraging behavior for our device. By alloying with BaSnO₃, we also explore the BaTiO₃-BaSnO₃ system for its potential advantages for energy conversion including control over dielectric constant and Curie temperature. We will analyze structure and composition through high resolution x-ray diffraction and x-ray photoelectron spectroscopy as well discuss their effect on dielectric and ferroelectric properties.

[1] A. Bucsek, W. Nunn, B. Jalan and R. D. James, "The Direct Conversion of Heat to Electricity Using First-Order Phase Transformations in Ferroelectrics" Phys. Rev. Appl. 12 (3), 034043 (2019)