We report the directly measured electronic structure of exfoliated monolayer molybdenum disulfide $\left(\mathrm{Mo}{\mathrm{S}}_2\right)$ using micrometer-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer $\mathrm{Mo}{\mathrm{S}}_2$ elucidate the effects of interaction with a substrate. A suggested relaxation of the in-plane lattice constant is found for both suspended and supported monolayer $\mathrm{Mo}{\mathrm{S}}_2$ crystals. For suspended $\mathrm{Mo}{\mathrm{S}}_2$, a careful investigation of the measured uppermost valence band gives an effective mass at $\overline{\Gamma }$ and $\overline{K}$ of $2.00m_0$ and $0.43m_0$, respectively. We also measure an increase in the band linewidth from the midpoint of $\overline{\Gamma K}$ to the vicinity of $\overline{K}$ and briefly discuss its possible origin.

• Received 2 June 2014

DOI:https://doi.org/10.1103/PhysRevB.91.121409