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Interlayer excitonic states in MoSe2/Mo S2 van der Waals heterostructures

Arora, A and Nayak, PK and Bhattacharyya, S and Maity, N and Singh, AK and Krishnan, A and Rao, MSR (2021) Interlayer excitonic states in MoSe2/Mo S2 van der Waals heterostructures. In: Physical Review B, 103 (20).

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Official URL: https://doi.org/10.1103/PhysRevB.103.205406


In the present work, we report different interlayer excitonic states of an aligned MoSe2/MoS2 incommensurate van der Waals (vdW) heterostructure (HS). The HS was fabricated by stacking chemical vapor deposited monolayers, and it was studied using photoluminescence (PL) measurements. We observed the emergence of two low-energy peaks in the PL spectrum of the HS measured at 100 K, which were absent in the constituent monolayers. The orbital resolved electronic band structure and the optical absorption considering the electron-hole interaction for these HSs were calculated using first-principles density functional theory simulations, which showed energy band hybridization and the presence of interlayer excitons (ILEs). Based on these observations, the peak at ∼1.57 eV was assigned to a momentum direct ILE, while the other peak at ∼1.35 eV showed feeble emission intensity and was assigned to a momentum indirect ILE. The emergence of both of these excitonic peaks in the HS PL spectrum can be attributed to the formation of a spatially periodic moiré potential at a nanometer length scale resulting in hybridization. Our results can help to understand the physics of ILEs and to engineer vdW HSs for efficient optoelectronic devices.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to American Physical Society.
Keywords: Band structure; Density functional theory; Hydraulic structures; Light absorption; Monolayers; Optoelectronic devices, Chemical vapor deposited; Electron-hole interactions; Electronic band structure; Emission intensity; First-principles density functional theory; Low-energy peaks; Nanometer length scale; Photoluminescence measurements, Van der Waals forces
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 13 Apr 2023 07:50
Last Modified: 13 Apr 2023 07:50
URI: https://eprints.iisc.ac.in/id/eprint/80604

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