Ultra-High‑<i>k</i> Ferroelectric\nBaTiO<sub>3</sub> Perovskite in the Gate Stack for Two-Dimensional\nWSe<sub>2</sub> p‑Type High-Performance Transistors

The experimental demonstration of a p-type 2D WSe<sub>2</sub> transistor\nwith a ferroelectric perovskite BaTiO<sub>3</sub> gate oxide is presented.\nThe 30 nm thick BaTiO<sub>3</sub> gate stack shows a robust ferroelectric\nhysteresis with a remanent polarization of 20 μC/cm<sup>2</sup> and further enables a capacitance equivalent thickness of 0.5 nm\nin the hybrid WSe<sub>2</sub>/BaTiO<sub>3</sub> stack due to its high\ndielectric constant of 323. We demonstrate one of the best ON currents\nfor perovskite gate 2D transistors in the literature. This is enabled\nby high-quality epitaxial growth of BaTiO<sub>3</sub> and a single\n2D layer transfer based fabrication method that is shown to be amenable\nto silicon platforms. This demonstration is an important milestone\ntoward the integration of crystalline complex oxides with 2D channel\nmaterials for scaled CMOS and low-voltage ferroelectric logic applications.