The electronic structure of epitaxial single-layer ${\mathrm{MoS}}_2$ on Au(111) is investigated by angle-resolved photoemission spectroscopy, scanning tunneling spectroscopy, and first-principles calculations. While the band dispersion of the supported single layer is close to a free-standing layer in the vicinity of the valence-band maximum at $\overline{K}$ and the calculated electronic band gap on Au(111) is similar to that calculated for the free-standing layer, significant modifications to the band structure are observed at other points of the two-dimensional Brillouin zone: at $\overline{\mathrm{\Gamma }}$, the valence-band maximum has a significantly higher binding energy than in the free ${\mathrm{MoS}}_2$ layer and the expected spin-degeneracy of the uppermost valence band at the $\overline{M}$ point cannot be observed. These band structure changes are reproduced by the calculations and can be explained by the detailed interaction of the out-of-plane ${\mathrm{MoS}}_2$ orbitals with the substrate.

Single-layer ${\mathrm{TaS}}_2$ is epitaxially grown on Au(111) substrates. The resulting two-dimensional crystals adopt the $1H$ polymorph. The electronic structure is determined by angle-resolved photoemission spectroscopy and found to be in excellent agreement with density functional theory calculations. The single-layer ${\mathrm{TaS}}_2$ is found to be strongly $n$ doped, with a carrier concentration of $0.3\left(1\right)$ extra electrons per unit cell. No superconducting or charge density wave state is observed by scanning tunneling microscopy at temperatures down to 4.7 K.