Controllable Synthesis of Nonlayered Ultrathin Mn3O4 with High Dielectric Constant

Two-dimensional (2D) materials have been identified as promising candidates for future electronic devices. However, high dielectric constant ( κ ) materials, which can be integrated with 2D semiconductors, are still very rare. This study employed a hydrate-assisted thinning chemical vapor deposition (CVD) technique combined with a strategy of minimizing substrate lattice mismatch, achieving precise control over the growth kinetics, enabling the controllable array growth of ultrathin manganese oxide (Mn ₃ O ₄ ), demonstrating an extraordinary dielectric constant of 237, an equivalent oxide thickness (EOT) as low as 0.57 nm, and a breakdown field strength ( E _bd ) exceeding 10 MV/cm, marking it as a superior gate dielectric material. MoS ₂ field-effect transistors (FETs) integrated with ultrathin Mn ₃ O ₄ through mechanical stacking method operate under ultra-low voltages (<1 V), achieving a near 10 ⁸ I _on / I _off ratio and a subthreshold swing (SS) as low as 84 mV/dec. The MoS ₂ FET exhibit nearly zero hysteresis (~5 mV) and an extremely low drain-induced barrier lowering (~20 mV/V). This work further expands the family of 2D high-κ dielectric materials and provides a feasible exploration for the epitaxial growth of single-crystal thin films of non-layered materials.