Controllable Synthesis of Nonlayered Ultrathin Mn3O4 with High Dielectric Constant

Abstract

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 (Mn3O4), demonstrating an extraordinary dielectric constant of 237, an equivalent oxide thickness (EOT) as low as 0.57 nm, and a breakdown field strength (Ebd) exceeding 10 MV/cm, marking it as a superior gate dielectric material. MoS2 field-effect transistors (FETs) integrated with ultrathin Mn3O4 through mechanical stacking method operate under ultra-low voltages (<1 V), achieving a near 108 Ion/Ioff ratio and a subthreshold swing (SS) as low as 84 mV/dec. The MoS2 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.