Tailored Vapor Deposition Unlocks Large‐Grain, Wafer‐Scale Epitaxial Growth of 2D Magnetic CrCl ₃

Abstract

ABSTRACT Two‐dimensional magnetic materials (2D‐MM) are an exciting playground for fundamental research, and for spintronics and quantum sensing. However, their large‐grain, wafer‐scale synthesis using scalable vapor deposition methods is still an unsolved challenge. Here, a tailored physical vapor transport deposition (PVTD) method is developed, which enables centimeter‐scale, epitaxial growth of semiconducting 2D‐MM CrCl 3 at 500°C (on mica substrate). A controlled synthesis protocol, enabled via four process innovations, (i) low emissivity secondary heating source, (ii) very‐high carrier‐gas flow, (iii) dynamic precursor flux control, and (iv) oxygen/moisture removal, suppresses redox etching and drives growth beyond the diffusion limit for wafer‐scale growth. Optical, stoichiometric, structural, and magnetic characterization confirm single‐crystalline, phase‐pure 2D‐MM CrCl 3 . Substrate temperature tunes thickness of films from few‐layers to tens of nanometers, while flow rate controls nucleation density and coverage. Further, we demonstrate selective‐area growth and large‐area transfer, validating potential wafer‐level device integration. Substrate‐dependent growth features are explained using density functional theory and state‐of‐the‐art machine learning interatomic potential‐based atomic‐scale simulations. This scalable, flexible vapor deposition approach offers a general route for synthesizing several (volatile and reactive) 2D‐MM and bridges the scalability gap from conventional wafer‐scale materials. The low‐temperature growth will enable the creation of hybrid functional heterostructures.