ARPES and Low-Energy Electron Microscopy Study on Supported, Suspended, and Bilayer Twisted MoS2

We report on the directly measured electronic structure of exfoliated monolayer molybdenum disulfide (MoS2) using micron-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer MoS2 elucidate the effects of interaction with a substrate. For suspended MoS2, a careful investigation of the measured uppermost valence band gives the effective mass at $\Gamma $ and K, and the estimated value of spin-orbit coupling induced splitting at K. Moreover, we prepare CVD synthesized twisted-bilayer MoS2 flakes on a native-oxide silicon substrate. Band structure of MoS2 for different twist angles is measured by using micro-ARPES, and their crystal orientations are determined by Micro-LEED. We investigate their dispersions, effective mass, and valence band maximum with respect to twist angle.