Anomalously polarised emission from a MoS₂/WS₂ heterostructure.

ABSTRACT: We report circularly polarised emission, with helicity opposite to the optical excitation, from a van der Waals heterostructure (HS) consisting of a monolayer MoS₂ and three-layer WS₂. Selective excitation of the MoS₂ layer confirms that this cross-polarized emission is due to the charge transfer from the WS₂ layers to the MoS₂ layer. We propose that the high levels of n-doping in the constituent layers due to sulphur vacancies and defects give rise to an enhanced transition rate of electrons from the k valley of WS₂ to the k' valley of MoS₂, which leads to the emission, counter polarized to the excitation. Simulations based on the rate equation model support this conclusion.

SUBMITTER: Mol PR 

PROVIDER: S-EPMC9417150 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature