Growth of monolayer 1T′-WTe2 with a nearly complete coverage

Monolayer WTe2, known for its intriguing properties as a quantum spin Hall insulator, presents significant challenges for high-quality epitaxial film growth. These difficulties primarily arise from the low mobility of W on the substrate and the reduced reaction rate between W and Te. This study addresses these challenges by employing a low-temperature deposition technique combined with the introduction of a Te buffer layer to mitigate these limitations. High-quality monolayer 1T′-WTe2 with nearly complete coverage has been grown on the SrTiO3 (100) substrate. Furthermore, scanning tunneling microscopy/spectroscopy demonstrates the presence of random domain orientations and variations in gap size within the monolayer WTe2. This approach offers a solution to the primary obstacles in WTe2 epitaxial growth and may be extended to other transition metal dichalcogenides.