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

We report a simple and scalable method to fabricate homogeneous transparent conductive thin films (Ti₂CT_<i>x</i>, one of the MXene) by dip coating of an Al₂O₃ substrate in a colloidal solution of large-area Ti₂CT_<i>x</i> thin flakes. Scanning electron microscopy and atomic force microscopy images exhibit the wafer-scale homogeneous Ti₂CT_<i>x</i> 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_<i>x</i> film layer by layer and removes the top oxidized layer without affecting the bottom layer of the Ti₂CT_<i>x</i> flake. The resistivity of plasma-treated Ti₂CT_<i>x</i> film is further decreased to 63 Ω/sq with an improved transmittance of 89% and FOM of 51.3, demonstrating the promise of Ti₂CT_<i>x</i> for future transparent conductive electrode application

Plasma-Treated Thickness-Controlled Two-Dimensional Black Phosphorus and Its Electronic Transport Properties

We report the preparation of thickness-controlled few-layer black phosphorus (BP) films through the modulated plasma treatment of BP flakes. Not only does the plasma treatment control the thickness of the BP film, it also removes the chemical degradation of the exposed oxidized BP surface, which results in enhanced field-effect transistor (FET) performance. Our fabricated BP FETs were passivated with poly(methyl methacrylate) (PMMA) immediately after the plasma etching process. With these techniques, a high field-effect mobility was achieved, 1150 cm²/(V s), with an <i>I</i>_on/<i>I</i>_off ratio of ∼10⁵ at room temperature. Furthermore, a fabricated FET with plasma-treated few-layer BP that was passivated with PMMA was found to retain its <i>I</i>–<i>V</i> characteristics and thus to exhibit excellent environmental stability over several weeks