Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, Key Laboratory for the Physics and Chemistry of Nanodevices, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871 (P.R. China); Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 (P.R. China).
Angew Chem Int Ed Engl. 2015 Feb 16;54(8):2366-9. doi: 10.1002/anie.201410108. Epub 2015 Jan 21.
An optical anisotropic nature of black phosphorus (BP) is revealed by angle-resolved polarized Raman spectroscopy (ARPRS), and for the first time, an all-optical method was realized to identify the crystal orientation of BP sheets, that is, the zigzag and armchair directions. We found that Raman intensities of Ag(1), B2g, and Ag(2) modes of BP not only depend on the polarization angle α, but also relate to the sample rotation angle θ. Furthermore, their intensities reach the local maximum or minimum values when the crystalline orientation is along with the polarization direction of scattered light (es). Combining with the angle-resolved conductance, it is confirmed that Ag(2) mode intensity achieves a relative larger (or smaller) local maximum under parallel polarization configuration when armchair (or zigzag) direction is parallel to es. Therefore, ARPRS can be used as a rapid, precise, and nondestructive method to identify the crystalline orientation of BP layers.
角分辨偏振拉曼光谱（ARPRS）揭示了黑磷（BP）的各向异性光学性质，首次实现了一种全光学方法来识别 BP 片的晶体取向，即锯齿形和扶手椅方向。我们发现 BP 的 Ag(1)、B2g 和 Ag(2)模式的 Raman 强度不仅取决于偏振角 α，还与样品旋转角 θ 有关。此外，当晶体取向与散射光的偏振方向（es）一致时，它们的强度达到局部最大值或最小值。结合角分辨电导，证实了当扶手椅（或锯齿形）方向与 es 平行时，Ag(2)模式强度在平行偏振配置下达到相对较大（或较小）的局部最大值。因此，ARPRS 可以用作一种快速、精确和非破坏性的方法来识别 BP 层的晶体取向。
