Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana, IL, 61801, USA.
Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA.
Adv Mater. 2017 Sep;29(35). doi: 10.1002/adma.201700650. Epub 2017 Jul 19.
ReS 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 ReS 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. ReS 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 K , as compared to transverse to the chains, (50 ± 13) W m K . 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 K , 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 ReS are discussed relative to the other 2D materials.
ReS 代表了一类不同的二维材料，其特点是具有低对称性，在平面内具有一维金属链，并且层间结合非常弱。在这里，通过时域热反射法确定了室温下单晶 ReS 在扭曲的 1T 相内平行于 Re 链和平行于平面方向以及贯穿平面方向的热导率。ReS 通过微机械剥离以厚度为 60-450nm 的薄片形式制备，并通过偏振拉曼光谱确定其晶体取向。与垂直于链方向相比，沿 Re 链方向的平面热导率更高，（70±18）W m K。由于层间结合较弱，与二维材料中迄今为止观察到的最低值相比，贯穿平面的热导率（0.55±0.07）W m K，导致两个平面方向的各向异性非常高，分别为（130±40）和（90±30）。讨论了 ReS 的热导率和界面热导与其他二维材料的关系。
