Credit: Research published in Surface Science, 660 (2017).
LEEM (a and b) was used to locate the sample area of interest, followed by dynamical LEED acquired at different electron energies (c, d, and e), to investigate the crystalline structure of molybdenum disulfide on a silicon substrate. The first LEEM image (a) shows bulk (more than 100 layers thick), monolayer (1 ML), bilayer (2 ML), and trilayer (3 ML) molybdenum disulfide. The second LEEM image (b) shows areas where circular holes were drilled and covered with 1 ML of molybdenum sulfide; without a substrate underneath, the 1 ML is "suspended." The dynamical LEED patterns are of bulk molybdenum disulfide, with c and e clearly displaying three-fold symmetry.