Ultra-High-k Ferroelectric BaTiO₃ Perovskite in the Gate Stack for Two-Dimensional WSe₂ p-Type High-Performance...

The experimental demonstration of a p-type 2D WSe₂ transistor with a ferroelectric perovskite BaTiO₃ gate oxide is presented. The 30 nm thick BaTiO₃ gate stack shows a robust ferroelectric hysteresis with a remanent polarization of 20 μC/cm² and further enables a capacitance equivalent thickness of 0.5 nm in the hybrid WSe₂/BaTiO₃ stack due to its high dielectric constant of 323. We demonstrate one of the best ON currents for perovskite gate 2D transistors in the literature. This is enabled by high-quality epitaxial growth of BaTiO₃ and a single 2D layer transfer based fabrication method that is shown to be amenable to silicon platforms. This demonstration is an important milestone toward the integration of crystalline complex oxides with 2D channel materials for scaled CMOS and low-voltage ferroelectric logic applications.