Sub-100 fs Formation of Dark Excitons in Monolayer WS₂.

ABSTRACT: Two-dimensional semiconducting transition metal dichalcogenides are promising materials for optoelectronic applications due to their strongly bound excitons. While bright excitons have been thoroughly scrutinized, dark excitons have been much less investigated, as they are not directly observable with far-field spectroscopy. However, with their nonzero momenta, dark excitons are significant for applications requiring long-range transport or coupling to external fields. We access such dark excitons in WS₂ monolayer using transient photoemission electron microscopy with subdiffraction limited spatial resolution (75 nm) and exceptionally high temporal resolution (13 fs). Image time series of the monolayer are recorded at several different fluences. We directly observe the ultrafast

SUBMITTER: Kolesnichenko PV 

PROVIDER: S-EPMC11583335 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature