Direct Integration and Deterministic Control of Freestanding Ferroic Oxides: From High-κ Membranes to Structural Variant Manipulation

Jan-Chi Yang^1*

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan

* Presenter:Jan-Chi Yang, email:janchiyang@phys.ncku.edu.tw

The direct integration and deterministic control of ferroic oxides represent key frontiers in the quest for reconfigurable, high-performance nanoelectronic systems. In this talk, I will present a comprehensive study that bridges the development of freestanding ferroelectric membranes with the fundamental manipulation of structural variants in complex oxides. I will begin with the realization of epitaxial freestanding ferroelectric hafnium zirconium oxide (Hf₀.₅Zr₀.₅O₂, HZO) membranes, which combine mechanical flexibility with robust ferroelectricity and high dielectric constants. These freestanding HZO (FS-HZO) films serve as high-κ top-gate dielectrics for two-dimensional (2D) semiconductor transistors, such as MoS₂. The resulting devices exhibit excellent performance, including a dielectric constant of ~19.5, low leakage current, an on/off ratio exceeding 10⁹, and subthreshold swings as low as 53 mV dec⁻¹. These results demonstrate the feasibility of integrating high-quality freestanding oxide membranes into next-generation 2D nanoelectronics.
Building upon the development of freestanding membranes, I will further discuss the deterministic manipulation of structural variants in perovskite antiferroelectrics. Using in situ transmission electron microscopy and phase-field simulations, we reveal that electron-beam irradiation and optical illumination can reversibly drive antipolar-to-polar transitions in PbZrO₃ at room temperature. The interplay between localized electric fields and light-induced screening charges enables precise domain reconfiguration, offering new opportunities for reprogrammable antiferroelectric functionalities. Together, these studies establish a unified framework linking the integration of freestanding ferroelectric oxides with the deterministic control of structural variants, paving the way for adaptive and multifunctional oxide-based nanoelectronic and quantum devices.

Keywords: freestanding menbrance, ferroelectrics, complex oxide, antiferroelectrics