Epitaxial fabrication of two-dimensional NiSe₂ on Ni(111) substrate

Two-dimensional (2D) transition metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, optoelectronics, and catalysis. A high-quality 2D film of NiSe₂, a TMD material, is grown epitaxially by a single step direct selenization of a Ni(111) substrate. X-ray photoemission spectroscopy, low-energy electron diffraction, scanning tunneling microscopy, and density functional theory calculations are combined to confirm the formation and structure of the film, revealing a (√3 × √3) superlattice of the NiSe₂ film formed on the (√7 × √7) superlattice of the substrate. Fabrication of this 2D NiSe₂ film opens opportunities to research its applications, especially for electrocatalysis and energy storage devices.