Creating vacancies in Ti3C2Tx MXene to enable inherent semiconductivity and electrical switching capabilities

Two-dimensional (2D) MXenes are renowned for the unique feature of strong metallic conductivity, whereas the lack of semiconductive nature has become a crucial bottleneck that impedes MXenes’ rapid development in electronic devices. The challenge mainly comes from the stringent requirements for specific 2D compositions, whose synthesis and/or exfoliation techniques are too difficult to succeed. Here we proposed a facile and universal approach for fabricating semiconductive MXenes. Our demonstration showed that through hydrothermal-assisted intercalation treatment of the prototypical MXene-Ti 3 C 2 T x , shallow and deep Ti-lattice vacancies can be generated in its 2D nanosheets, weakening the original strong metallicity and even facilitating the wide-bandgap semiconductivity. Reciprocating bias polarization on the semiconductive 2D-Ti 3 C 2 T x nanosheet can induce reversible electrochemical-like migration of the surface anionic ligands, which enables high-nonlinearity and ultralow-current electrical switching capabilities for potential volatile selector applications. Our idea opens a new avenue for tuning the physical and chemical properties of MXenes, promoting their wide applications, especially in the field of 2D electronics.