State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST) , Wuhan 430074, P.R. China.
Department of Physics, Southern University of Science and Technology , Shenzhen 518055, P.R. China.
ACS Nano. 2017 Oct 24;11(10):10264-10272. doi: 10.1021/acsnano.7b04860. Epub 2017 Sep 18.
An interesting in-plane anisotropic layered dimetal chalcogenide TaNiS is introduced, and the optical and electrical properties with respect to its in-plane anisotropy are systematically studied. The Raman vibration modes have been identified by Raman spectra measurements combined with calculations of phonon-related properties. Importantly, the TaNiS flakes exhibit strong anisotropic Raman response under the angle-resolved polarized Raman spectroscopy measurements. We found that Raman intensities of the A mode not only depend on rotation angle but are also related to the sample thickness. In contrast, the infrared absorption with light polarized along the a axis direction is always larger than that in the c axis direction regardless of thickness under the polarization-resolved infrared spectroscopy measurements. Remarkably, the first-principles calculations combined with angle-resolved conductance measurements indicate strong anisotropic conductivity of TaNiS. Our results not only prove TaNiS is a promising in-plane anisotropic 2D material but also provide an interesting platform for future functionalized electronic devices.
我们介绍了一种有趣的面内各向异性层状双金属硫属化物 TaNiS，并系统地研究了其面内各向异性对光学和电学性能的影响。通过拉曼光谱测量结合声子相关性质的计算，确定了拉曼振动模式。重要的是，在角度分辨偏振拉曼光谱测量下，TaNiS 薄片表现出强烈的各向异性拉曼响应。我们发现，A 模的拉曼强度不仅取决于旋转角度，而且与样品厚度有关。相比之下，在偏振分辨红外光谱测量下，无论厚度如何，沿 a 轴方向极化的红外吸收总是大于沿 c 轴方向的红外吸收。值得注意的是，结合角度分辨电导测量的第一性原理计算表明 TaNiS 具有很强的各向异性电导率。我们的结果不仅证明了 TaNiS 是一种很有前途的面内各向异性二维材料，而且为未来的功能化电子器件提供了一个有趣的平台。
