Electronic structure of thin MoS2 films†

The valence electron structure of exfoliated monolayer MoS₂ deposited onto SiO₂ was determined by UV photoelectron spectroscopy through component analysis in combination with Auger electron microscopy. The valence electron cut-off for bulk MoS₂ was found at 0.64 eV binding energy whilst monolayer MoS₂ and few layer MoS₂ have higher binding energies of 0.89 eV and 1.26 eV respectively. SiO₂ is known to interact only weakly with MoS₂. Thus, the valence electron structure of higher binding energy determined here is thus considered to represent that of a material not affected by strain. The implications of the change in the valence electron cut-off are discussed.