Anisotropic charge transport in 2D single crystals of Ti3C2Tx MXenes
Oriane de Leuze, Fernando Massa Fernandes, Sofiane Arib, Laura Caputo, Ana Pedro Fontes, Việt Hùng Nguyễn, Hanna Pazniak, Bernard Nysten, Jean‐Christophe Charlier, Sophie Hermans, B. Hackens
Abstract
Charge transport in two-dimensional crystals is critical for a large variety of future applications, and it is therefore highly desirable to get a better understanding of the underlying mechanisms. Here, we focus on the MXene Ti3C2Tx, which has recently garnered significant attention for its potential in printable electronics, energy storage and electromagnetic interference shielding, for which electrical properties play a leading role. To answer the need for experimental data on charge transport in Ti3C2Tx, we combine local-probe measurements (Conductive AFM), conventional four-contact measurements, finite element and ab initio simulations on individual few-layer flakes of Ti3C2Tx. This effort establishes new methods to study charge transport both in in-plane and out-of-plane directions and yields a consistent quantitative value of resistivity anisotropy in individual Ti3C2Tx flakes, an essential ingredient in the understanding and modeling of charge transport in MXenes, in particular considering the role of interlayer interactions and surface functionalization in these materials. Accessing charge transport along the out-of-plane direction in 2D crystals is challenging, yet essential to understanding their anisotropic properties. Here, both in-plane and out-of-plane transport are measured in Ti3C2Tx with experimental and computational tools, enabling quantitative analysis.