Blue-shifted and strongly-enhanced light emission in transition-metal dichalcogenide twisted heterobilayers

Moiré heterostructures produced by twisted heterojunction of transition-metal dichalcogenides are recognized as novel platforms for unique and tunable means of controlling the optical phenomena including photoluminescence (PL). Despite some interesting results on the PL peak shifts by the heterojunc...

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Bibliographic Details
Published in:NPJ 2D materials and applications 2022-05, Vol.6 (1), p.1-7, Article 36
Main Authors: Ko, Jung Sun, Jang, Chan Wook, Lee, Won Jun, Kim, Jae Kuk, Kim, Hyeong Ku, Liu, Boqing, Lu, Yuerui, Crosse, J. A., Moon, Pilkyung, Kim, Sung, Choi, Suk-Ho
Format: Article
Language:English
Subjects:
639/301/930/527/1819
639/766/119/1000/1018
639/766/930/2735
639/766/930/527/1821
Behavior
Chalcogenides
Chemistry and Materials Science
Energy
Excitons
Heterojunctions
Heterostructures
Interlayers
Light
Light emission
Materials Science
Microscopy
Molybdenum disulfide
Nanotechnology
Optoelectronic devices
Photoluminescence
Physics
Surfaces and Interfaces
Thin Films
Transition metal compounds
Tungsten disulfide
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Summary:Moiré heterostructures produced by twisted heterojunction of transition-metal dichalcogenides are recognized as novel platforms for unique and tunable means of controlling the optical phenomena including photoluminescence (PL). Despite some interesting results on the PL peak shifts by the heterojunction at twist angles ( θ ) far from 0 or 60°, all of them are redshifts. Here, we first report blue shift of energy and strong enhancement of intensity in the PL by twisted heterojunction of MoS 2 and WS 2 monolayers (MLs) in a particular range of θ . The PL peak energy of the heterobilayer steeply increases (about 120 meV) as θ gets closer to 15 or 52° from 3 or 57°, respectively and reaches a plateau at around 2.01 eV in the θ range from 15 to 52°, higher than that of the separate MoS 2 or WS 2 ML. The PL intensity shows a similar θ -dependent behavior with its magnitude in the plateau being ∼4 or 80 times larger than that of the WS 2 or MoS 2 ML, respectively. These novel light-emission behaviors are well explained with reference to theoretical predictions on the avoided crossing between the intralayer and interlayer excitons. Our findings highlight extendable tuning and remarkable enhancement of light emission from two-dimensional semiconductors by a simple approach of twisted heterojunction in a proper θ range, very useful for their optoelectronic device applications.
ISSN:2397-7132
2397-7132
DOI:10.1038/s41699-022-00308-6