paper

Defect healing and charge transfer mediated valley polarization in MoS $_{2}$ /MoSe $_{2}$ /MoS $_{2}$ trilayer van der Waals heterostructures

arXiv:1703.00806 · doi:10.1021/acs.nanolett.7b00904

Abstract

Monolayer transition metal dichalcogenides (TMDC) grown by chemical vapor deposition (CVD) are plagued by a significantly lower optical quality compared to exfoliated TMDC. In this work we show that the optical quality of CVD-grown MoSe $_{2}$ is completely recovered if the material is sandwiched in MoS $_{2}$ /MoSe $_{2}$ /MoS $_{2}$ trilayer van der Waals heterostructures. We show by means of density-functional theory that this remarkable and unexpected result is due to defect healing: S atoms of the more reactive MoS $_{2}$ layers are donated to heal Se vacancy defects in the middle MoSe $_{2}$ layer. In addition, the trilayer structure exhibits a considerable charge-transfer mediated valley polarization of MoSe $_{2}$ without the need for resonant excitation. Our fabrication approach, relying solely on simple flake transfer technique, paves the way for the scalable production of large-area TMDC materials with excellent optical quality.

Just accepted for publication in Nano Letters (http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b00904)

Defect healing and charge transfer mediated valley polarization in MoS2​/MoSe2​/MoS2​ trilayer van der Waals heterostructures

Abstract

Defect healing and charge transfer mediated valley polarization in MoS $_{2}$ /MoSe $_{2}$ /MoS $_{2}$ trilayer van der Waals heterostructures