Fabrication of atomically thin nanowire for mesoscopic transport study*

Layered transition metal chalcogenides(TMC) have attracted tremendous attention owing to their weak van der Waals(vdW) interactions between chalcogens, allowing easy mechanical exfoliation of single atomic layer from the bulk. We extend this idea of “exfoliating layers” to “exfoliating atomic chains” in Ta₂(Pd or Pt)₃Se₈, which is a vdW bonded stack of molecular strands. In this work, we succeeded to achieve Ta₂Pd₃Se₈ single and few molecular thin (0.7nm, 1.3nm, 2nm) wires through micromechanical exfoliation. High-resolution TEM confirms 1D chain like morphology of these wires. In addition, we also demonstrated that this method can be applied to other isostructures, such as Ta₂Pt₃Se₈. We also discovered that intrinsic semiconducting properties can be largely preserved in the Ta₂Pd₃Se₈ nanowire transistor as evidenced by high on/off ratio (up to 10⁴) and mobility (up to 80 cm²V^-1s^-1). Finally, our work provides a new strategy for obtaining air-stable and strictly 1D material system, which offers excellent opportunities for the study of 1D physics.