Anisotropy of lattice vibrations and optoelectronic properties in layered KGaS2 single crystal

Low-dimensional materials have the potential for application in polarization-sensitive optoelectronic devices. In this work, we systematically investigated the lattice vibration and photoelectric properties of low-symmetry KGaS2 single crystals. The temperature-dependent Raman spectroscopy revealed the linear dependence of Raman modes on temperatures. The first-order temperature coefficient (χ) of the KGaS2 Raman mode ranges from −0.006 95 to −0.031 09 cm−1/K. Angle-resolved polarized Raman spectroscopy demonstrates the anisotropy of lattice vibrations. Interestingly, KGaS2 exhibits anisotropic transport behavior with a conductance ratio of 6.5 and a photocurrent ratio of about 1.6. The results demonstrate that KGaS2 is a promising candidate material for fabricating polarization-sensitive photodetectors and ignite future research interest in layered AIBIIIQ2VI compounds.