Abstract
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.
Highlights
The growth of large-area epitaxial transition metal dichalgogenides (TMDCs) are of central importance for scalable integrated device applications
chemical vapor deposition (CVD) growth of micrometer-sized 2D WSe2 structures has been well developed, it typically requires high temperature process (700 to 1300 °C) and has the limits of the substrates used for the synthesis[16,17,18,19]
Inspired by the selenization method widely used in the fabrication of Cu(In1−xGax)Se2 (CIGS) solar cells[23,24], here we report a new method for large-area epitaxial WSe2 synthesis on SiO2/Si substrates
Summary
The growth of large-area epitaxial transition metal dichalgogenides (TMDCs) are of central importance for scalable integrated device applications. 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. CVD growth of micrometer-sized 2D WSe2 structures has been well developed, it typically requires high temperature process (700 to 1300 °C) and has the limits of the substrates used for the synthesis[16,17,18,19]. Large-area CVD prepared WSe2 films on glass substrates at a lower temperature from reaction of WCl6 and diethyl diselenide have been reported[15], but they are composed of either platelet or needle like crystalline structure with different orientations. Through a vapor transfer method[21,22], highly textured WSe2 films have been fabricated on insulating substrates, films with high crystallinity and scalability are still lacking. A mechanism involved with the formation of a self-assembled PtSe2 buffer layer has been proposed
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