The role of momentum-dark excitons in the elementary optical response of bilayer WSe₂.

ABSTRACT: Monolayer transition metal dichalcogenides (TMDs) undergo substantial changes in the single-particle band structure and excitonic optical response upon the addition of just one layer. As opposed to the single-layer limit, the bandgap of bilayer (BL) TMD semiconductors is indirect which results in reduced photoluminescence with richly structured spectra that have eluded a detailed understanding to date. Here, we provide a closed interpretation of cryogenic emission from BL WSe₂ as a representative material for the wider class of TMD semiconductors. By combining theoretical calculations with comprehensive spectroscopy experiments, we identify the crucial role of momentum-indirect excitons for the understanding of BL TMD emission. Our results shed light on the origin of quantum dot

SUBMITTER: Lindlau J 

PROVIDER: S-EPMC6030057 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature