Rubing Li

Raman spectroscopy is an indispensable method for the nondestructive testing of semiconductor materials and their microstructures. This paper presents a study on the angle-resolved intensity of polarized micro-Raman spectroscopy for a 4H silicon carbide (4H-SiC) wafer. A generalized theoretical model of polarized Raman intensity was established by considering the birefringence effect. The distributions of angle-resolved Raman intensities were achieved under normal and oblique backscattering configurations. Experiments were performed on a self-built angle-resolved Raman system, which verified the validity of the proposed model and achieved the identification of crystal orientations of the 4H-SiC sample.

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_g¹ and A_g² 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_g¹ and A_g² 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_2g mode. The results show that B_2g 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_2g mode. The new method can accurately identify the crystalline orientation with different layers of black phosphorus without misidentification.

The unique photoelectric properties of phosphorene typically include anisotropy, hence the nondestructive and rapid identification of its crystal orientation is a key point to the investigation and application of phosphorene. Currently, the orientation identification by analyzing the A_g¹ mode based on parallel-polarized Raman has severe requirements for the applicable Raman system. Therefore, it is necessary to develop a more general, convenient, and accurate method for determining the crystal orientation of phosphorene. In this paper, a method of orientation identification was proposed by using a Raman system without an analyzer and quantifying the correlation between the intensities of A_g¹ and A_g² modes with the change of the incident polarization direction. By using mechanically peeled phosphorene as specimens, Raman measurements were carried out under the Raman configurations of both parallel polarization and with no analyzer. The results show that the crystal orientation of phosphorene can be accurately identified by quantifying the Raman intensities of both A_g¹ and A_g² modes using the Raman system without an analyzer.