Band Structure Engineering of Monolayer MoS2 by Surface Ligand Functionalization
Monolayer transition metal dicalcogenide (TMDC) materials are currently attracting extensive attention due to their distinctive electronic, transport, and optical properties. For example, monolayer MoS2 exhibits a direct band gap in the visible frequency range, which makes it an attractive candidate for the photocatalytic water splitting. For the photoelectrochemical water splitting, the appropriate band edge positions that overlap with the water redox potential are necessary. Similarly, appropriate band level alignments will be crucial for the light emitting diode and photovoltaic applications utlizing heterojunctions between two TMDC materials. Carrying out first-principles calculations, we here investigate how the band edges of MoS2 can be adjusted by surface ligand functionalization. This study will provide useful information for the realization of ligand-based band engineering of monolayer MoS2 for various electronic, energy, and bio device applications.