A high-$\kappa$ wide-gap layered dielectric for two-dimensional van der Waals heterostructures

TL;DR

This paper introduces a reproducible method to synthesize LaOBr, a 2D layered dielectric with high dielectric constant and wide bandgap, suitable for advanced van der Waals heterostructure devices.

Contribution

It reports the first synthesis and exfoliation of LaOBr as a 2D layered dielectric with high performance in electronic and excitonic devices.

Findings

LaOBr has a dielectric constant of approximately 9.

LaOBr exhibits a wide bandgap of 5.3 eV.

LaOBr enables high-performance van der Waals transistors with low interface defects.

Abstract

Van der Waals heterostructures of two-dimensional materials have opened up new frontiers in condensed matter physics, unlocking unexplored possibilities in electronic and photonic device applications. However, the investigation of wide-gap high-$\kappa$ layered dielectrics for devices based on van der Waals structures has been relatively limited. In this work, we demonstrate an easily reproducible synthesis method for the rare earth oxyhalide LaOBr, and we exfoliate it as a 2D layered material with a measured static dielectric constant of $\epsilon_{0, \perp} \simeq 9$ and a wide bandgap of 5.3 eV. Furthermore, our research demonstrates that LaOBr can be used as a high-$\kappa$ dielectric in van der Waals field-effect transistors with high performance and low interface defect concentrations. Additionally, it proves to be an attractive choice for electrical gating in excitonic devices based on 2D materials. Our work demonstrates the versatile realization and functionality of 2D systems with wide-gap and high-$\kappa$ van der Waals dielectric environments.