# High‐κ Perovskite‐Like Ternary Niobium Oxide Dielectrics for 2D Electronics

## TL;DR

This paper introduces new niobium oxide materials as high-performance dielectrics for 2D electronics, showing excellent properties for transistors and logic gates.

## Contribution

The paper presents a new class of ternary niobium oxides with high dielectric constants and stability for 2D electronics.

## Key findings

- The oxides show high dielectric constants (up to 68) and wide bandgaps (~4 eV).
- MoS2 transistors with these dielectrics achieve low subthreshold swings and high ON/OFF ratios.
- NOT and NAND gates using CaNb2O6 show low power consumption and high gain.

## Abstract

High‐κ dielectrics with exceptional interface quality are essential for the field‐effect control of nanoscale transistors. However, their design remains challenging due to competing atomic‐scale polarization requirements. Here, we demonstrate nonlayered perovskite‐like ternary niobium oxides (CaNb2O6, KNb3O8, and Na2Nb4O11) as promising candidates, where strong Nb 4d‐O 2p covalent hybridization enables pronounced Nb5+ ionic displacements and enhanced polarization, while ionic bonding from intercalated Ca/K/Na suppresses electronic transitions, widening the bandgap and enhancing stability via configurational entropy. We successfully synthesize these high‐quality nanoflakes through a scalable molten‐salt method. Crucially, these oxides demonstrate a combination of high dielectric constants (∼16, 9, and 68 for CaNb2O6, KNb3O8, and Na2Nb4O11, respectively), wide bandgaps (∼4 eV), large breakdown field strengths (> 4.9 MV cm−1), and excellent air stability. Furthermore, due to the low‐contamination transfer via a fully dry process, MoS2 field‐effect transistors with these gate dielectrics achieve low subthreshold swings (∼60 mV dec−1), ON/OFF ratios > 107, gate leakage currents below 10−6 A cm−2, and ultralow trap densities. We show high‐performance NOT and NAND gates using a CaNb2O6 dielectric layer, with the inverter achieving a static power consumption of < 0.02 µW and a gain of ∼20. This work provides new opportunities for the development of next‐generation 2D electronics devices.

High‐κ dielectrics are vital for scaled electronics. Here, a family of 2D high‐κ perovskite‐like ternary niobium oxides is synthesized via a molten salt‐assisted method. Their integration into FETs and logic gates reveals superior switching characteristics, providing a fresh material platform and new insights for the advancement of high‐performance 2D electronics.