Visualizing Hot-Carrier Expansion and Cascaded Transport in WS₂ by Ultrafast Transient Absorption Microscopy.

ABSTRACT: The competition between different spatiotemporal carrier relaxation determines the carrier harvesting in optoelectronic semiconductors, which can be greatly optimized by utilizing the ultrafast spatial expansion of highly energetic carriers before their energy dissipation via carrier-phonon interactions. Here, the excited-state dynamics in layered tungsten disulfide (WS₂ ) are primarily imaged in the temporal, spatial, and spectral domains by transient absorption microscopy. Ultrafast hot carrier expansion is captured in the first 1.4 ps immediately after photoexcitation, with a mean diffusivity up to 980 cm² s^-1 . This carrier diffusivity then rapidly weakens, reaching a conventional linear spread of 10.5 cm² s^-1 after 2 ps after the

SUBMITTER: Liu Q 

PROVIDER: S-EPMC8981895 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature