Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
Nanoscale. 2017 Oct 5;9(38):14558-14564. doi: 10.1039/c7nr05047j.
In-plane anisotropy in optical, electronic and thermal properties of two-dimensional (2D) materials has attracted significant interest because of the huge potential applications for developing novel devices. In this work, outstanding angle-dependent Raman property of layered SnSe nano-plates is obtained via polarized Raman system and it is confirmed that the Raman polarization directions of two A modes (130 cm and 150 cm) are consistent with specific crystalline directions (zigzag direction or armchair direction) of SnSe flakes under parallel polarization configuration at home temperature and low temperature. Furthermore, the SnSe nano-plate devices show excellent angle-resolved photo-response at home temperature and low temperature (150 K) with a 90° cycle period and the polarized directions are also along zigzag direction and armchair direction, which is ascribed to the unique in-plane asymmetric crystal structure. These prominent in-plane anisotropic properties provide a precise and rapid method to determine the crystal orientation of SnSe nano-flakes and open up the new applications of 2D asymmetric structure materials.
二维（2D）材料的各向同性在光学、电子和热性能方面引起了人们的极大兴趣，因为开发新型器件具有巨大的潜在应用。在这项工作中，通过偏振拉曼系统获得了层状 SnSe 纳米板出色的角度相关拉曼特性，并证实了在室温及低温下，平行偏振配置下，两种 A 模（130cm 和 150cm）的拉曼偏振方向与 SnSe 薄片的特定晶向（锯齿方向或扶手椅方向）一致。此外，SnSe 纳米板器件在室温及低温（150K）下具有出色的角度分辨光响应，周期为 90°，偏振方向也沿锯齿方向和扶手椅方向，这归因于其独特的面内非对称晶体结构。这些突出的面内各向异性特性为确定 SnSe 纳米片的晶体取向提供了一种精确、快速的方法，并为二维非对称结构材料的新应用开辟了道路。
