Abstract
We study the electronic structure of a heterojunction made of two monolayers of MoS and WS. Our first-principles density functional calculations show that, unlike in the homogeneous bilayers, the heterojunction has an optically active band gap, smaller than the ones of MoS and WS single layers. We find that the optically active states of the maximum valence and minimum conduction bands are localized on opposite monolayers, and thus the lowest energy electron-holes pairs are spatially separated. Our findings portray the MoS-WS bilayer as a prototypical example for band-gap engineering of atomically thin two-dimensional semiconducting heterostructures.
- Received 10 December 2012
DOI:https://doi.org/10.1103/PhysRevB.87.075451
©2013 American Physical Society