Crystalline Orientation Identification of Multilayer Black Phosphorus Based on the Ag 1 and Ag 2 Raman Modes for an Orthogonally Polarized Configuration

As an anisotropic material, the unique optoelectronic properties of black phosphorus are obviously anisotropic. Therefore, nondestructive and fast identification of its crystalline orientation is an important condition for its application in the optoelectronics research field. In the existing parallel polarization (PP) and nonanalyzer configurations, when the crystalline orientations of black phosphorus with different thicknesses are identified through the Ag 1 and Ag 2 modes, the direction of the maximum Raman intensity changes between armchair (AC) and zigzag (ZZ), making it difficult to determine the crystalline direction. This work proposes a new method to identify the crystalline orientation by comprehensively analyzing the Ag 1 and Ag 2 modes under the configuration of orthogonal polarization (OP). The experimental results show that the crystalline orientation results for different thicknesses of black phosphorus are consistent with those of the new method proposed in this work.