title: Probing charge transfer excitons in a MoSe2-WS2 van der Waals heterostructure.
abstract: We show that the van der Waals heterostructure formed by MoSe2 and WS2 provides a unique system with near degenerate interlayer and intralayer excitonic states. Photoluminescence measurements indicate that the charge transfer exciton states are approximately 50 meV below the MoSe2 exciton states, with a significant spectral overlap. The transient absorption of a femtosecond pulse was used to study the dynamics of the charge transfer excitons at room temperature. We found a lifetime of approximately 80 ps for the charge transfer excitons. A diffusion coefficient of about 14 cm(2) s(-1) was deduced, which is comparable to individual excitons in transition metal dichalcogenides.
authors.affiliation: Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, USA. huizhao@ku.edu.
authors.forename: Frank
authors.initials: F
authors.lastname: Ceballos
authors.forename: Matthew Z
authors.initials: MZ
authors.lastname: Bellus
authors.forename: Hsin-Ying
authors.initials: HY
authors.lastname: Chiu
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao