3D Anisotropic Thermal Conductivity of Exfoliated Rhenium Disulfide

5 years ago

3D Anisotropic Thermal Conductivity of Exfoliated Rhenium Disulfide

David G. Cahill, Mark C. Hersam, Christopher R. Ryder, Joshua D. Wood, Hyejin Jang

ReS2 represents a different class of 2D materials, which is characterized by low symmetry having 1D metallic chains within the planes and extremely weak interlayer bonding. Here, the thermal conductivity of single-crystalline ReS2 in a distorted 1T phase is determined at room temperature for the in-plane directions parallel and perpendicular to the Re-chains, and the through-plane direction using time-domain thermoreflectance. ReS2 is prepared in the form of flakes having thicknesses of 60–450 nm by micromechanical exfoliation, and their crystalline orientations are identified by polarized Raman spectroscopy. The in-plane thermal conductivity is higher along the Re-chains, (70 ± 18) W m−1 K−1, as compared to transverse to the chains, (50 ± 13) W m−1 K−1. As expected from the weak interlayer bonding, the through-plane thermal conductivity is the lowest observed to date for 2D materials, (0.55 ± 0.07) W m−1 K−1, resulting in a remarkably high anisotropy of (130 ± 40) and (90 ± 30) for the two in-plane directions. The thermal conductivity and interface thermal conductance of ReS2 are discussed relative to the other 2D materials. The 3D thermal-conductivity tensor of ReS2, a transition-metal dichalcogenide with Re-chains on the plane, is determined using time-domain thermoreflectance. The thermal conductivity is higher along the Re-chains, 70 W m−1 K−1, compared to transverse to the chains, 50 W m−1 K−1. The through-plane thermal conductivity is the lowest observed for 2D materials, 0.55 W m−1 K−1.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adma.201700650