Unidirectional Alignment of AgCN Microwires on Distorted Transition Metal Dichalcogenide Crystals

Abstract

Van der Waals epitaxy on the surface of two-dimensional (2D) layered crystals has gained significant research interest for the assembly of well-ordered nanostructures and fabrication of vertical heterostructures based on 2D crystals. Although van der Waals epitaxial assembly on the hexagonal phase of transition metal dichalcogenides (TMDCs) has been relatively well characterized, a comparable study on the distorted octahedral phase (1T' or Td) of TMDCs is largely lacking. Here we investigate the assembly behavior of one-dimensional (1D) AgCN microwires on various distorted TMDC crystals, namely 1T'-MoTe2, Td-WTe2, and 1T'-ReS2. The unidirectional alignment of AgCN chains is observed on these crystals, reflecting the symmetry of underlying distorted TMDCs. Polarized Raman spectroscopy and transmission electron microscopy directly confirm that AgCN chains display the remarkable alignment behavior along the distorted chain directions of underlying TMDCs. The observed unidirectional assembly behavior can be attributed to the favorable adsorption configurations of 1D chains along the substrate distortion, which is supported by our theoretical calculations and observation of similar assembly behavior from different cyanide chains. The aligned AgCN microwires can be harnessed as facile markers to identify polymorphs and crystal orientations of TMDCs.

23 pages, 6 main figures

References in corpus (8)

• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• The Valley Hall Effect in MoS2 Transistors
• Mixed-Dimensional van der Waals Heterostructures
• Engineering the structural and electronic phases of MoTe2 through W substitution
• Activation of new Raman modes by inversion symmetry breaking in type II Weyl semimetal candidate T'-MoTe2
• Raman scattering in transition metal dichalcogenides MTe2 (M = Mo, W)
• Complete determination of crystallographic orientation of ReX2 (X=S, Se) by polarized Raman spectroscopy
• Determination of the thickness and orientation of few-layer tungsten ditelluride using polarized Raman spectroscopy