Raman Spectroscopy Application in Anisotropic 2D Materials

In recent years, anisotropic 2D materials (black phosphorus, ReS₂, WTe₂, etc.) have garnered significant attention due to their orientation-dependent physical and chemical properties, along with their potential applications in micro-nano device development, such as crystal-based diodes, polarized light photodetectors, and directional heat transfer. As a practical, quick, and nondestructive characterization tool, Raman spectroscopy, with its unique and unmatched advantages in studying anisotropic materials, plays a crucial role. It enables lattice orientation identification, investigation of structural phase transitions, and examination of anisotropic lattice vibrations, among other aspects. Here, a comprehensive review of recent developments in Raman spectroscopy research on anisotropic materials is provided. To begin, this study introduces the classification of anisotropic materials before delving into the polarized Raman spectroscopy principle. Various research directions of Raman spectroscopy in anisotropic materials are explored, including lattice orientation identification, temperature dependence, interlayer coupling, electron–phonon interaction, thickness dependence, and high-pressure phase transition. Finally, potential future directions in the field of Raman spectroscopy for anisotropic materials are discussed, and the potential challenges that may arise are addressed.