WSe ₂ Monolayers Grown by Molecular Beam Epitaxy on hBN

High Resolution Image Download MS PowerPoint Slide A three-step process was developed for growing high-quality, optically uniform WSe 2 monolayers by molecular beam epitaxy (MBE), taking advantage of the use of hexagonal boron nitride (hBN) as a substrate. The process was optimized to maximize the efficiency of photoluminescence and promote the formation of hexagonal WSe 2 domains. Atomic force microscopy was employed to estimate the dispersion of the WSe 2 hexagonal domains' orientation. Monolayer character of the film was identified using optical methods and verified with a high-resolution transmission electron microscopy cross-section. Temperature- and magnetic-field-dependent studies revealed the behavior of exciton complexes to be analogous to that of exfoliated counterparts. Direct growth on hBN, combined with a uniform optical response, proves that MBE-grown WSe 2 is superior to mechanically exfoliated WSe 2 in terms of the convenience of use and reproducibility. The provided results establish significant progress in the optical quality of epitaxially grown transition-metal dichalcogenide monolayers and the fabrication of large-scale functional devices.