The Integration of Freestanding Perovskite Ferroelectrics with Two-Dimensional Materials for Low-Power Ferroelectric Field Effect Transistors

Perovskite ferroelectrics with low coercive field and high crystal quality consume low write energy, which are promising for low-power memory and data-intensive applications. Ferroelectric field effect transistors (FeFETs) demonstrate remarkable energy efficiency due to the non-volatile retention and non-destructive read operation. However, the growth of high-quality perovskite ferroelectrics requires lattice-match substrates, high temperature, and oxygen atmosphere, which restricts their integration with semiconductor and insulator.<b> </b>Here we epitaxially deposit the BiFeO₃ on the sacrificial Sr₃Al₂O₆ layer, then transfer freestanding BiFeO₃ films and integrate with two-dimensional materials for metal-ferroelectric-metal-insulator-semiconductor (MFMIS) FeFETs. The freestanding BiFeO₃ films exhibit low coercive field (30 kV/cm) and low current leakage (10^-6 A/cm²). The van der Waals integration with two-dimensional (2D) materials realizes low interfacial trap density (<i>D</i>_it~10¹¹ cm^-2eV^-1), which contributes to efficient gate control and low write voltage. The resulting ferroelectric transistors show low write energy of 10^-20 J. This work establishes a promising route by integrating high-quality perovskite ferroelectrics for various high-performance electronic devices and physical science.