Orientation Identification of the Black Phosphorus with Different Thickness Based on B Mode Using a Micro-Raman Spectroscope under a Nonanalyzer Configuration.

As an anisotropic material, the unique optoelectronic properties of black phosphorus are obviously anisotropic. Therefore, non-destructive and fast identification of its crystalline orientation is an important condition for its application in optoelectronics research field. Identifying the crystalline orientation of black phosphorus through A and A modes under the parallel polarization has high requirements on the Raman system, while in the nonanalyzer configuration, the crystalline orientation of the thick black phosphorus may not be identified through A and A modes. This work proposes a new method to identify the crystalline orientation of black phosphorus of different thicknesses. This method is conducted under the nonanalyzer configuration by B mode. The results show that B mode has a good consistency in the identification of crystalline orientations. In this paper, a theoretical model is established to study the angle-resolved Raman results of B mode. The new method can accurately identify the crystalline orientation with different layers of black phosphorus without misidentification.