Tunable electronic and optical properties of a type-II violet phosphorus/ZrS2 heterojunction: First-principles calculation

Constructing two-dimensional (2D) van der Waals (vdW) heterojunctions is an effective strategy for tuning the electronic structures and optical response of 2D materials. This study systematically investigates the interfacial stability, electronic structure, interfacial charge transfer, and optical response of the VP/ZrS2 vdW heterojunction based on first-principles calculations. Our results demonstrate that the optimized configuration has an interfacial binding energy of −5.07 eV and maintains structural integrity during molecular dynamics simulations at 300 K. The VP/ZrS2 heterojunction exhibits a type-II indirect bandgap with a value of 0.53 eV. A potential drop of about 3.67 eV is formed at the interface, accompanied by interfacial charge transfer from VP to ZrS2, which may provide favorable conditions for carrier separation across the interface. The optical calculations show that the VP/ZrS2 heterojunction has stronger absorption than the individual monolayers in the ultraviolet and visible regions, and it also shows a certain degree of anisotropy. Further strain calculations indicate that tensile strain causes a blue shift of the absorption edge, while compressive strain is more favorable for enhancing absorption in the near-infrared region. When the compressive strain reaches −6% and −8%, band overlap appears and the system exhibits metallic characteristics. These results suggest that the VP/ZrS2 heterojunction has potential value for the design of tunable 2D optoelectronic materials and for studies on optical response modulation.