Synthesis of Epitaxial Single-Layer MoS₂ on Au(111)

الأصل · EN

We present a method for synthesizing large area epitaxial single-layer MoS₂ on the Au(111) surface in ultrahigh vacuum. Using scanning tunneling microscopy and low energy electron diffraction, the evolution of the growth is followed from nanoscale single-layer MoS₂ islands to a continuous MoS₂ layer. An exceptionally good control over the MoS₂ coverage is maintained using an approach based on cycles of Mo evaporation and sulfurization to first nucleate the MoS₂ nano-islands and then gradually increase their size. During this growth process the native herringbone reconstruction of Au(111) is lifted as shown by low energy electron diffraction measurements. Within these MoS₂ islands, we identify domains rotated by 60∘ that lead to atomically sharp line defects at domain boundaries. As the MoS₂ coverage approaches the limit of a complete single-layer, the formation of bilayer MoS₂ islands is initiated. Angle-resolved photoemission spectroscopy measurements of both single and bilayer MoS₂ samples show a dramatic change in their band structure around the center of the Brillouin zone. Brief exposure to air after removing the MoS₂ layer from vacuum is not found to affect its quality.