Localized interlayer excitons in MoSe2–WSe2 heterostructures without a moiré potential

Fateme Mahdikhanysarvejahany; Daniel N. Shanks; Matthew Klein; Qian Wang; Michael R. Koehler; David G. Mandrus; Takashi Taniguchi; Kenji Watanabe; Oliver L. A. Monti; Brian J. LeRoy; John R. Schaibley

doi:10.1038/s41467-022-33082-6

Article Localized interlayer excitons in MoSe2–WSe2 heterostructures without a moiré potential

Fateme Mahdikhanysarvejahany ; Daniel N. Shanks ; Matthew Klein ; Qian Wang ; Michael R. Koehler ; David G. Mandrus ; Takashi Taniguchi (National Institute for Materials Science) ; Kenji Watanabe (National Institute for Materials Science) ; Oliver L. A. Monti ; Brian J. LeRoy ; John R. Schaibley

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Fateme Mahdikhanysarvejahany, Daniel N. Shanks, Matthew Klein, Qian Wang, Michael R. Koehler, David G. Mandrus, Takashi Taniguchi, Kenji Watanabe, Oliver L. A. Monti, Brian J. LeRoy, John R. Schaibley. Localized interlayer excitons in MoSe2–WSe2 heterostructures without a moiré potential. Nature Communications. 2022, 13 (1), 5354. https://doi.org/10.1038/s41467-022-33082-6

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Trapped interlayer excitons (IXs) in MoSe2-WSe2 heterobilayers have generated interest for use as single quantum emitter arrays and an opportunity to study moiré physics in transition metal dichalcogenide (TMD) heterostructures. IXs are spatially indirectly excitons comprised of an electron in the MoSe2 layer bound to a hole in the WSe2 layer. Previous reports of spectrally narrow (<1 meV) photoluminescence (PL) emission lines at low temperature have been attributed to IXs localized by the moiré potential between the TMD layers. Here, we show that spectrally narrow IX PL lines are present even when the moiré potential is suppressed by inserting a bilayer hBN spacer between the TMD layers. We directly compare the doping, electric field, and magnetic field, and temperature dependence of IXs in a directly contacted MoSe2-WSe2 region to those separated by bilayer hBN. Our results show that the localization potential resulting in the narrow PL lines is independent of the moiré potential, and instead likely due to extrinsic effects such as nanobubbles or defects. We show that while the doping, electric field, and temperature dependence of the narrow IX lines is similar for both regions, their excitonic g-factors have opposite signs, indicating that the IXs in the directly contacted region are trapped by both moiré and extrinsic localization potentials.

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