Orientation Identification of the Black Phosphorus with Different Thickness Based on B2g Mode Using a Micro-Raman Spectroscope under a Nonanalyzer Configuration

Abstract

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 Ag1 and Ag2 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 Ag1 and Ag2 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 B2g mode. The results show that B2g 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 B2g mode. The new method can accurately identify the crystalline orientation with different layers of black phosphorus without misidentification.

Nanoscale Evaluation of the Degradation Stability of Black Phosphorus Nanosheets Functionalized with PEG and Glutathione-Stabilized Doxorubicin Drug-Loaded Gold Nanoparticles in Real Functionalized System

“…The three phonon modes (A 1 g , B 2g , and A 2 g ) of the BP-PEG@Au-GSH-DOX spectrum are redshifted due to the oscillation hindrance of phosphorus atoms by interacting with PEG and Au, thus reducing the corresponding Raman scattering energy. This observation further confirms the successful functionalization of BP to synthesize the BP-PEG@Au-GSH-DOX nanoconjugate [54][55][56].…”

Anisotropic Generation and Detection of Coherent Ag Phonons in Black Phosphorus

“…Here, the time-domain beating is a signature of multiple phonon modes. The Fourier transformation (FT) spectrum in Figure 2c indicates that the CP signal consists of two dominant frequencies, 10.72 and 13.88 THz, which correspond to the Ag 1 and Ag 2 symmetry optical phonons of orthorhombic BP crystal [18][19][20][21]26,27]. As shown in Figure 2c, the phosphorous atoms move largely in the out-of-plane (in-plane) direction within the Ag 1 (Ag 2 ) mode.…”

“…Additionally, the anisotropic electron-phonon interaction in BP leads to strongly polarization-dependent Raman scattering behaviors [18][19][20][21][22][23][24][25], where sensitive changes by layer thickness were explained by the interference effect of either the incident or the scattered light [18]. Recently, Raman scattering with an orthogonal polarization configuration and the B 2g Raman mode under a nonanalyzer configuration were demonstrated to be useful in identifying the crystalline orientation of BP [26,27].…”

Angle-Resolved Intensity of Polarized Micro-Raman Spectroscopy for 4H-SiC

“…Due to its nondestructive, noncontact, in situ, and highly sensitive characteristics, Raman spectroscopy has been successfully applied to the field of semiconductor materials and two-dimensional materials [4][5][6]. The Raman spectra of semiconductor crystals contain structural and physical information, including crystal orientation [7], doping [8], grain size [9], stress/strain [10], and electron mobility [11]. Therefore, these properties can be characterized by quantitative analysis of the intensity, wavenumber, full width at half maximum (FWHM), and symmetry through the Raman spectra of the samples.…”