Band gap engineering and vibrational properties of van der Waals semiconductor ZnPSe₃ under compression

In recent years, transition metal phosphorus trichalcogenides MPX₃ (M = transition metal, X = S, Se) have garnered significant attention in the field of two-dimensional van der Waals materials on account of their unique layered structures and diverse physical properties. In this work, we systematically investigated the vibrational modes and band gap evolution of ZnPSe₃ under extreme conditions using Raman spectroscopy and high-pressure ultraviolet–visible (UV-vis) absorption spectroscopy. The experimental results demonstrate that the vibrational modes of ZnPSe₃ remain stable at low temperatures (5–300 K) and high pressures (0–22.1 GPa). Notably, the band gap of ZnPSe₃ exhibits an initial increase followed by a decrease under pressures ranging from 0 to 20.6 GPa, which is likely associated with a pressure-induced transition from an indirect to a direct band gap. This work not only enriches the understanding of van der Waals materials but also provides crucial experimental insights for their application in band gap engineering.