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S-Vacancy induced indirect-to-direct band gap transition in multilayer MoS

Two-dimensional (2D) MoS 2 has various potential applications due to its attractive band gap of 1.29-1.90 eV and unique photoelectric properties. Furthermore, it is well-known that multilayer and bulk MoS 2 structures possess an indirect band gap. In this paper, however, our first-principles calcula...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2020-11, Vol.22 (44), p.265-2614
Main Authors: Zhu, Bingyu, Lang, Junyu, Hu, Yun Hang
Format: Article
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Summary:Two-dimensional (2D) MoS 2 has various potential applications due to its attractive band gap of 1.29-1.90 eV and unique photoelectric properties. Furthermore, it is well-known that multilayer and bulk MoS 2 structures possess an indirect band gap. In this paper, however, our first-principles calculations demonstrated that the creation of S vacancies in the multilayer and bulk MoS 2 structures can achieve indirect-to-direct band gap transition, leading to a decrease in the band gap energies from 0.984-1.542 eV to 0.629-0.971 eV. Although the generation of Mo vacancies cannot cause such indirect-to-direct band gap transition, the Mo vacancies also decrease the band gap energies of the multilayer and bulk MoS 2 structures to 0.369-0.460 eV. Furthermore, the band gap energy of the vacancy-defected multilayer MoS 2 decreases with the increasing number of layers. Optical properties are also remarkably affected by atomic vacancies, that is, the absorption edges in the defect structures of MoS 2 present a redshift and significantly enhance the visible light absorption compared to the corresponding pristine structures. These findings provide a novel approach to tuning the electronic structure and dielectric properties of MoS 2 for specific future applications. Two-dimensional (2D) MoS 2 has a tunable band structure.
ISSN:1463-9076
1463-9084
DOI:10.1039/d0cp04201c