Scalable Epitaxial Growth of WSe₂ Thin Films on SiO₂/Si via a Self-Assembled PtSe₂ Buffer Layer

The growth of large-area epitaxial transition metal dichalgogenides (TMDCs) are of central importance for scalable integrated device applications. Different methods have been developed to achieve large-sized high quality films. However, reliable approaches for centimeter-sized or even wafer-level epitaxial growth of TMDCs are still lacking. Here we demonstrate a new method to grow inch-sized epitaxial WSe₂ films on SiO₂/Si substrates at a much lower temperature with high repeatability and scalability. High quality crystalline films are achieved through direct selenization of a tungsten film with platinum as the underlayer. The self-assembled PtSe₂ buffer layer, formed during selenization, assists epitaxial growth of WSe₂. Using fabricated WSe₂ films, excellent performance memory devices are demonstrated. As a member of the TMDC family, our findings based on WSe₂ may also be applied to other TMDC materials for large-scale production of high quality TMDC films for various applications.