Direct Fabrication of Functional Ultrathin Single-Crystal Nanowires from Quasi-One-Dimensional van der Waals Crystals

Micromechanical exfoliation of two-dimensional (2D) van der Waals materials has triggered an explosive interest in 2D material research. The extension of this idea to 11) van der Waals materials, possibly opening a new arena for ID material research, has not yet been realized. In this paper, we demonstrate that 1D nanowire with sizes as small as six molecular ribbons, can be readily achieved in the Ta-2(Pd or Pt)(3)Se-8 system by simple micromecharAcal exfoliation. Exfoliated Ta2Pd3Se8 nanowires are a-type semiconductors, whereas isostructural Ta2Pt3Se8 nanowires are p-type semiconductors. Both types of nanowires show excellent electrical switching performance as the channel material for a field-effect transistor. Low-temperature transport measurement reveals a defect level inherent to Ta2Pd3Se8 nanowires, which enables the observed electrical switching behavior at high temperature (above 140 K). A functional logic gate consisting of both in-type Ta2Pd3Se8 and p-type Ta2Pt3Se8 field-effect transistors has also been successfully achieved. By taking advantage of the high crystal quality derived from the parent van der Wags bulk compound, our findings about the exfoliated Ta-2(Pd or Pt)(3)Se-8 nanowires demonstrate a new pathway to access single-crystal 1D nanostructures for the study of their fundamental properties and the exploration of their applications in electronics, optoelectronics, and energy harvesting.