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Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2
Seohui Kang1, Yonas Assefa Eshete2, Sujin Lee1
1Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
Iscience
|January 6, 2022
Summary
We demonstrate tunable bandgaps in tungsten disulfide (WS₂) monolayers using core-shell structures. This method enables the creation of lateral heterostructures with distinct optical bandgaps for optoelectronic devices.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Tunable bandgaps in tungsten disulfide (WS₂) are crucial for advanced optoelectronic devices.
- Achieving controlled bandgap modulation in 2D materials remains a key challenge.
Purpose of the Study:
- To report bandgap modulation in WS₂ monolayers via 2D core-shell structures.
- To investigate the effects of strain and doping on WS₂ bandgaps.
- To provide a method for fabricating lateral heterostructures with distinct optical bandgaps.
Main Methods:
- Chemical vapor deposition (CVD) to grow WS₂ monolayers with core-shell structures.
- Optical imaging, Raman spectroscopy, and photoluminescence (PL) spectroscopy for characterization.
- Density functional theory (DFT) calculations to understand bandgap modulation mechanisms.
Main Results:
- Core-shell structures in WS₂ monolayers were successfully synthesized using CVD.
- Distinct PL peaks at 1.83 eV (core) and 1.98 eV (shell) were observed, differing from conventional WS₂ (2.02 eV).
- DFT calculations confirmed strain-induced bandgap modulation and a direct-to-indirect bandgap transition.
Conclusions:
- Core-shell structured WS₂ monolayers offer a practical approach to engineer lateral heterostructures.
- The ability to create distinct optical bandgaps is vital for next-generation optoelectronic applications.
- This work presents a pathway for fabricating functional optoelectronic devices using WS₂.
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