Anisotropic Superconducting Nb₂CT_x MXene Processed by Atomic Exchange at the Wafer Scale

Abstract

The recent successful induction of superconductivity in MXenes through surface modification significantly expands the exploration space for MXene‐based physical properties. However, relevant investigations were mostly based on powders or cold‐pressed pellets, with few about the intrinsic superconductive properties at the nanoscale. Here we show that, after an atomic exchange process of aqueous‐acid‐synthesized Nb2CTx in the NH3 atmosphere, the superconductivity can be induced to either the single‐flake or the thin film of the Nb2CTx MXene. The exchange process between nitrogen atoms and fluorine, carbon, and oxygen atoms on the MXene lattice and related structure evolutions were studied using both experiments and density functional theory (DFT). Based on either single‐flake or thin‐film devices, the anisotropic magnetic response of the two‐dimensional superconducting transformation has been successfully uncovered. The anisotropic superconductivity indicates the great potential of MXenes with rich and unique physical properties. Moreover, the processing of the superconducting thin film uniformly over a 4‐inch wafer opens up a space for scalable MXene‐based devices.This article is protected by copyright. All rights reserved

Raman Spectroscopy and Laser-Induced Surface Modification of Nb2CTx MXene

“…They are synthesized through selective etching of the A atoms (Al, Si, Ga) from a MAX phase and follow the general formula of M n +1 X n T x , where M is an early transition metal, n = 1–4, X is carbon or nitrogen, and T x represents surface terminal groups, such as oxygen, hydroxyl, chalcogens or halogens. , Ti 3 C 2 T x , the flagship titanium-based MXene, has dominated the field since this material’s discovery in 2011 due to its robust electrical conductivity and increasing synthetic accessibility. However, many other MXenes based on alternative transition metals have been synthesized and even more theoretically predicted. ,, Nb 2 CT x , a niobium-based MXene, has garnered particular interest due to its potential for applications in energy storage, biomedical devices, catalysis, and sensors due to its low ion transport barrier, favorable photocatalytic properties, hydrophilic surface, large surface area, acceptable chemical and electrochemical stabilities, and excellent mechanical flexibility. ,− MXenes are typically characterized using methods such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, the third of which is arguably the most common technique for characterizing 2D materials. In addition to structural information, Raman spectroscopy provides insights into lattice strain and surface modification, including defects.…”