Temperature-Dependent Phase Variations in Van Der Waals CdPS3 Revealed by Raman Spectroscopy

In addition to graphene, the transition metal dichalcogenides, black phosphorus and multiple other layered materials have undergone immense investigations. Among them, metal thiophosphates (MPS_x) have emerged as a promising material for various applications. While several layered metal thiophosphates with general-formula MPS_x have been scrutinized extensively, van der Waals (vdW) CdPS₃ has been overlooked in the literature. Here we report on the extensive Raman scattering of layered CdPS₃, showing structural phase transition at a low temperature. The emergence of multiple new peaks at low frequency and a significant shift in peak position with temperature implied a probable change in crystal symmetry from trigonal D_3d to triclinic C_i below the phase transition temperature, T_K~180 K. In addition, we also showed a p-type performance of CdPS₃ FET fabricated using Au electrodes. This work adds CdPS₃ to the list of potential layered materials for energy application.