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

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

Nat Commun. 2022 Sep 12;13(1):5354. doi: 10.1038/s41467-022-33082-6.

Authors

Affiliations

¹ Department of Physics, University of Arizona, Tucson, AZ, 85721, USA.
² Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing & School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai, 519082, China.
³ IAMM Diffraction Facility, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, TN, 37920, USA.
⁴ Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA.
⁵ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
⁶ Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.
⁷ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁸ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁹ Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA.
¹⁰ Department of Physics, University of Arizona, Tucson, AZ, 85721, USA. johnschaibley@email.arizona.edu.

Abstract

Interlayer excitons (IXs) in MoSe₂-WSe₂ heterobilayers have generated interest as highly tunable light emitters in transition metal dichalcogenide (TMD) heterostructures. 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. We show that spectrally narrow IX PL lines are present even when the moiré potential is suppressed by inserting a bilayer hexagonal boron nitride (hBN) spacer between the TMD layers. We compare the doping, electric field, magnetic field, and temperature dependence of IXs in a directly contacted MoSe₂-WSe₂ region to those in a region separated by bilayer hBN. The doping, electric field, and temperature dependence of the narrow IX lines are similar for both regions, but their excitonic g-factors have opposite signs, indicating that the origin of narrow IX PL is not the moiré potential.

Grants and funding

DMR-2003583/National Science Foundation (NSF)