Time-Resolved Arpes Determination Of A Quasi-Particle Band Gap And Hot Electron Dynamics In Monolayer Mos2

The electronic structure and dynamics of 2D transition metal dichalcogenide (TMD) monolayers provide important underpinnings both for understanding the many-body physics of electronic quasi-particles and for applications in advanced optoelectronic devices. However, extensive experimental investigations of semiconducting monolayer TMDs have yielded inconsistent results for a key parameter, the quasi-particle band gap (QBG), even for measurements carried out on the same layer and substrate combination. Here, we employ sensitive time- and angle-resolved photoelectron spectroscopy (trARPES) for a high-quality large-area MoS2 monolayer to capture its momentumresolved equilibrium and excited-state electronic structure in the weakexcitation limit. For monolayer MoS2 on graphite, we obtain QBG values of similar to 2.10 eV at 80 K and of similar to 2.03 eV at 300 K, results well-corroborated by the scanning tunneling spectroscopy (STS) measurements on the same material.