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Robust Direct Bandgap Characteristics of One- and Two-Dimensional ReS2.

Yu ZG, Cai Y, Zhang YW - Sci Rep (2015)

Bottom Line: Two-dimensional (2D) transition-metal dichalcogenides (TMDs), most notably, MoS2 and WS2, have attracted significant attention due to their sizable and direct bandgap characteristics.In addition, the direct bandgap of ReS2 nanoribbons is only weakly dependent on their width.These robust characteristics strongly suggest that ReS2 has great potential for applications in optoelectronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Institute of High Performance Computing, Singapore 138632, Singapore.

ABSTRACT
Two-dimensional (2D) transition-metal dichalcogenides (TMDs), most notably, MoS2 and WS2, have attracted significant attention due to their sizable and direct bandgap characteristics. Although several interesting MoS2 and WS2-based optoelectronic devices have been reported, their processability and reproducibility are limited since their electrical properties are strongly dependent of the number of layers, strain and sample sizes. It is highly desirable to have a robust direct bandgap TMD, which is insensitive to those factors. In this work, using density functional theory, we explore the effects of layer number, strain and ribbon width on the electronic properties of ReS2, a new member in the TMD family. The calculation results reveal that for monolayer ReS2, the nature (direct versus indirect) and magnitude of its bandgap are insensitive to strain. Importantly, the predicted bandgap and also charge carrier mobilities are nearly independent of the number of layers. In addition, the direct bandgap of ReS2 nanoribbons is only weakly dependent on their width. These robust characteristics strongly suggest that ReS2 has great potential for applications in optoelectronic nanodevices.

No MeSH data available.


Related in: MedlinePlus

The optimized model of RY-S8Re4 NR unitcell.
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f4: The optimized model of RY-S8Re4 NR unitcell.

Mentions: where ERB is the total energy of the ReS2 NR, and is the energy of ReS2 unitcell calculated from the monolayer. L is the length of NRs. nS,(Re) is the number of extra S or Re atoms at the edges, respectively. μS,(Re) is the chemical potentials of S or Re, respectively. It should be noted that the chemical potentials of Re and S are decided by the thermodynamics condition. For ReS2, at equilibrium, we have , where is the chemical potential of ReS226. The calculated edge energies of bare NRs as well as 3D view of their corresponding NR configurations are shown in Fig. 3. It is seen that RY-S8Re4 has the minimum edge energy. Consequently, we only focus on exploring the electronic properties of RY-S8Re4 NR. The optimized structure of RY-S8Re4 NR is shown in Fig. 4.


Robust Direct Bandgap Characteristics of One- and Two-Dimensional ReS2.

Yu ZG, Cai Y, Zhang YW - Sci Rep (2015)

The optimized model of RY-S8Re4 NR unitcell.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562306&req=5

f4: The optimized model of RY-S8Re4 NR unitcell.
Mentions: where ERB is the total energy of the ReS2 NR, and is the energy of ReS2 unitcell calculated from the monolayer. L is the length of NRs. nS,(Re) is the number of extra S or Re atoms at the edges, respectively. μS,(Re) is the chemical potentials of S or Re, respectively. It should be noted that the chemical potentials of Re and S are decided by the thermodynamics condition. For ReS2, at equilibrium, we have , where is the chemical potential of ReS226. The calculated edge energies of bare NRs as well as 3D view of their corresponding NR configurations are shown in Fig. 3. It is seen that RY-S8Re4 has the minimum edge energy. Consequently, we only focus on exploring the electronic properties of RY-S8Re4 NR. The optimized structure of RY-S8Re4 NR is shown in Fig. 4.

Bottom Line: Two-dimensional (2D) transition-metal dichalcogenides (TMDs), most notably, MoS2 and WS2, have attracted significant attention due to their sizable and direct bandgap characteristics.In addition, the direct bandgap of ReS2 nanoribbons is only weakly dependent on their width.These robust characteristics strongly suggest that ReS2 has great potential for applications in optoelectronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Institute of High Performance Computing, Singapore 138632, Singapore.

ABSTRACT
Two-dimensional (2D) transition-metal dichalcogenides (TMDs), most notably, MoS2 and WS2, have attracted significant attention due to their sizable and direct bandgap characteristics. Although several interesting MoS2 and WS2-based optoelectronic devices have been reported, their processability and reproducibility are limited since their electrical properties are strongly dependent of the number of layers, strain and sample sizes. It is highly desirable to have a robust direct bandgap TMD, which is insensitive to those factors. In this work, using density functional theory, we explore the effects of layer number, strain and ribbon width on the electronic properties of ReS2, a new member in the TMD family. The calculation results reveal that for monolayer ReS2, the nature (direct versus indirect) and magnitude of its bandgap are insensitive to strain. Importantly, the predicted bandgap and also charge carrier mobilities are nearly independent of the number of layers. In addition, the direct bandgap of ReS2 nanoribbons is only weakly dependent on their width. These robust characteristics strongly suggest that ReS2 has great potential for applications in optoelectronic nanodevices.

No MeSH data available.


Related in: MedlinePlus