Anisotropic Optical and Mechanical Properties in Few-Layer GaPS4

Low-symmetry 2D materials have received tremendous attention due to their anisotropic optical, electrical, and mechanical properties and viable candidates for polarized photodetectors, anisotropic field-effect transistors, and nanomechanical systems. Here, an interesting low-symmetry 2D material (GaPS4) is reported and its in-plane anisotropic structure, optical, and mechanical properties are investigated. The polarized Raman and absorption spectra prove the sensitivity of GaPS4 to crystalline orientation and linear dichroism. The experimental results of azimuth-dependent reflectance difference microscopy can visually reveal the in-plane optical anisotropy of GaPS4 flakes. Moreover, an interesting pressurized bubble method is designed to verify the anisotropic mechanical properties of GaPS4 flakes and saddle-like bubble devices of GaPS4 are successfully fabricated. The saddle-like bubble devices exhibit visual anisotropic deflection variations along the orthogonal direction. Kelvin probe force microscope enables the direct identifying of the surface potential distribution of bubble devices under strain. Interest would be excited in the anisotropic optical and mechanical properties and relevant device applications of low-symmetry 2D materials.

Automated summary

This study reports on an interesting low-symmetry 2D material, GaPS4, and investigates its in-plane anisotropic structure, optical, and mechanical properties. The experimental results show that GaPS4 is sensitive to crystalline orientation and linear dichroism. An interesting pressurized bubble method is used to verify the anisotropic mechanical properties of GaPS4, and saddle-like bubble devices of GaPS4 are successfully fabricated.