Two-dimensional (2D) layered dielectrics offers a compelling route towards the design of next-generation ultimately compact nanoelectronics. Motivated by recent high-throughput computational prediction of LaOX (X = Br, Cl) as an exceptional 2D dielectrics that significantly outperforms HfO2 even in the monolyaer limit, we investigate the interface properties between LaOX and the archetypal 2D semiconductors of monolayer transition metal dichacolgenides (TMDCs) MS2 (M = Mo, W) using first-principle density functional theory simulations. We show that LaOX monolayers interacts weakly with MS2 via van der Waals forces with negligible hybridization and interfacial charge transfer, thus conveniently preserving the electronic properties of 2D TMDCs upon contact formation. The conduction and valance band offsets of the interfaces exhibit a sizable value ranging from 0.7 to 1.4 eV, suggesting the capability of LaOX as a gate dielectric materials. Based on Murphy-Good electron emission model, we demonstrate that LaOCl/MoS2 is a versatile dielectric/semiconductor combinations that are compatible to both NMOS and PMOS applications with leakage current lower than 10−7 Acm−2, while LaOX/WS2 is generally compatible with PMOS application. The presence of an interfacial tunneling potential barrier at the van der Waals gap further provide an additional mechanism to suppress the leakage current. Our findings reveal the role LaOX as an excellent dielectric companion to 2D TMDC and shall provide useful insights for leveraging the dielectric strength of LaOX in the design of high-performance 2D nanodevices.
@article{arxiv.2210.17295,
title = {Lanthanum Oxyhalide Monolayers: An Exceptional Dielectric Companion to Two-Dimensional Semiconductors},
author = {Zhuoling Jiang and Tong Su and Cherq Chua and L. K. Ang and Chun Zhang and Liemao Cao and Yee Sin Ang},
journal= {arXiv preprint arXiv:2210.17295},
year = {2023}
}