Large-Area Highly Conductive Transparent Two-Dimensional Ti₂CT_<i>x</i> Film

Abstract

We report a simple and scalable method to fabricate homogeneous transparent conductive thin films (Ti₂CT_x, one of the MXene) by dip coating of an Al₂O₃ substrate in a colloidal solution of large-area Ti₂CT_x thin flakes. Scanning electron microscopy and atomic force microscopy images exhibit the wafer-scale homogeneous Ti₂CT_x thin film (∼5 nm) covering the whole substrate. The sheet resistance is as low as 70 Ω/sq at 86% transmittance, which corresponds to the high figure of merit (FOM) of 40.7. Furthermore, the thickness of the film is tuned by a SF₆+Ar plasma treatment, which etches Ti₂CT_x film layer by layer and removes the top oxidized layer without affecting the bottom layer of the Ti₂CT_x flake. The resistivity of plasma-treated Ti₂CT_x film is further decreased to 63 Ω/sq with an improved transmittance of 89% and FOM of 51.3, demonstrating the promise of Ti₂CT_x for future transparent conductive electrode application.