Effect of distance on photoluminescence quenching and proximity-induced spin-orbit coupling in graphene-WSe2 heterostructures

Abstract

Spin-orbit coupling (SOC) in graphene can be greatly enhanced by proximity coupling it to transition metal dichalcogenides (TMDs) such as WSe2. 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., SiO2/graphene/WSe2/h-BN exhibiting stronger SOC than SiO2/WSe2/graphene/h-BN. We utilize photoluminescence (PL) as an indicator to characterize the interaction between graphene and monolayer WSe2 grown by chemical vapor deposition. We observe much stronger PL quenching in the SiO2/graphene/WSe2/h-BN stack than in the SiO2/WSe2/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 WSe2, 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 WSe2 in these two stacks.

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Cited by in corpus (11)

• Gate tunability of highly efficient spin-to-charge conversion by spin Hall effect in graphene proximitized with WSe${}_2$
• Unconventional charge-to-spin conversions in graphene/MoTe2 van der Waals heterostructures
• Exposing the trion's fine structure by controlling the carrier concentration in hBN-encapsulated MoS${}_2$
• Impacts of dielectric screening on the luminescence of monolayer WSe${}_2$
• Quantum Geometric Exciton Drift Velocity
• Influence of interface-induced valley-Zeeman and spin-orbit couplings\\ on transport in graphene-on-WSe${}_2$ heterostructures
• Landau Levels of Bilayer Graphene in a WSe${}_2$/Bilayer Graphene van der Waals Heterostructure
• Atomically-precise synthesis and simultaneous integration of 2D transition metal dichalcogenides enabled by nano-confinement
• Valley Gapless Semiconductor: Models and Applications
• Electrical Control of Excitons in Bare-MoSe2 and MoSe2/NbSe2 Heterostructure
• Ultrafast Spin Injection in Graphene via Dynamical Carrier Filtering at Transition Metal Dichalcogenide Interfaces