Probing the Formation of Dark Interlayer Excitons via Ultrafast Photocurrent.

ABSTRACT: Optically dark excitons determine a wide range of properties of photoexcited semiconductors yet are hard to access via conventional time-resolved spectroscopies. Here, we develop a time-resolved ultrafast photocurrent technique (trPC) to probe the formation dynamics of optically dark excitons. The nonlinear nature of the trPC makes it particularly sensitive to the formation of excitons occurring at the femtosecond time scale after the excitation. As a proof of principle, we extract the interlayer exciton formation time of 0.4 ps at 160 μJ/cm² fluence in a MoS₂/MoSe₂ heterostructure and show that this time decreases with fluence. In addition, our approach provides access to the dynamics of carriers and their interlayer transport. Overall, our work establishe

SUBMITTER: Yagodkin D 

PROVIDER: S-EPMC10603811 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature