title: Synthesis of Epitaxial Single-Layer MoS2 on Au(111).
abstract: 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 nanoislands 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 the 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.
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Signe S
authors: SS
authors: Grønborg
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Søren
authors: S
authors: Ulstrup
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Marco
authors: M
authors: Bianchi
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Maciej
authors: M
authors: Dendzik
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Charlotte E
authors: CE
authors: Sanders
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Jeppe V
authors: JV
authors: Lauritsen
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Philip
authors: P
authors: Hofmann
authors: Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , 8000 Aarhus, Denmark.
authors: Jill A
authors: JA
authors: Miwa