Effect of Distance on Photoluminescence Quenching and Proximity-Induced Spin-Orbit Coupling in Graphene/WSe<sub>2</sub> Heterostructures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29852737.
- Also identified by DOI 10.1021/acs.nanolett.8b00691.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Spin-orbit coupling (SOC) in graphene can be greatly enhanced by proximity coupling it to transition metal dichalcogenides (TMDs) such as WSe<sub>2</sub>. We find that the strength of the acquired SOC in graphene depends on the stacking order of the heterostructures when using hexagonal boron nitride ( h-BN) as the capping layer, i.e., SiO<sub>2</sub>/graphene/WSe<sub>2</sub>/ h-BN exhibiting stronger SOC than SiO<sub>2</sub>/WSe<sub>2</sub>/graphene/ h-BN. We utilize photoluminescence (PL) as an indicator to characterize the interaction between graphene and monolayer WSe<sub>2</sub> grown by chemical vapor deposition. We observe much stronger PL quenching in the SiO<sub>2</sub>/graphene/WSe<sub>2</sub>/ h-BN stack than in the SiO<sub>2</sub>/WSe<sub>2</sub>/graphene/ h-BN stack and, correspondingly, a much larger weak antilocalization (WAL) effect or stronger induced SOC in the former than in the latter. We attribute these two effects to the interlayer distance between graphene and WSe<sub>2</sub>, which depends on whether graphene is in immediate contact with h-BN. Our observations and hypothesis are further supported by first-principles calculations, which reveal a clear difference in the interlayer distance between graphene and WSe<sub>2</sub> in these two stacks.