Controllable crystal restructuring in MXene by electron irradiation

TL;DR

This paper demonstrates that electron irradiation can precisely manipulate atoms in MXene multilayers, enabling controllable crystal restructuring that enhances electrical properties and offers new avenues for atomic-scale engineering.

Contribution

It introduces a novel method for controllably restructuring MXene crystals using electron beams, overcoming previous challenges of random atom manipulation.

Findings

Electron irradiation removes hydroxyl H atoms, creating cation traps.

Transition metal atoms migrate into traps, causing crystal restructuring.

Restructuring improves electrical conductivity and reduces anisotropy.

Abstract

Recent decades have witnessed the breakthroughs in utilizing electron beams as the smallest tools to tailor materials. Whereas, the manipulation of atoms in a controllable manner by the electron beams is a long-time challenge due to the random nature of atom-knock-on. Here, we show that electron irradiation can controllably manipulate atoms in newly-developed MXene multilayers. The multilayers consist of many few-atom-thick transition metal carbide slabs that are terminated with hydroxyl and O functional groups on each slab. Upon electron irradiation, the H atoms of the hydroxyl are knocked off, creating cation traps surrounded by dangling O confined in a nano-sized slit. Simultaneously, the transition metal atoms partially struck away from the carbide slabs migrate into the cation traps periodically, resulting in crystal restructuring. Crystal restructuring is versatile for various MXenes and dramatically improves the electric conductivity and lessens the anisotropy, holding significant implications in engineering MXenes at the atomic scale.