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Controlling the Electronic Structures and Properties of in-Plane Transition-Metal Dichalcogenides Quantum Wells.

Wei W, Dai Y, Niu C, Huang B - Sci Rep (2015)

Bottom Line: The true type-II alignment forms due to the coherent lattice and strong interface coupling suggesting the effective separation and collection of excitons.The intrinsic electric polarization enhances the spin-orbital coupling and demonstrates the possibility to achieve topological insulator state and valleytronics in TMD quantum wells.In-plane TMD quantum wells have opened up new possibilities of applications in next-generation devices at nanoscale.

View Article: PubMed Central - PubMed

Affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.

ABSTRACT
In-plane transition-metal dichalcogenides (TMDs) quantum wells have been studied on the basis of first-principles density functional calculations to reveal how to control the electronic structures and the properties. In collection of quantum confinement, strain and intrinsic electric field, TMD quantum wells offer a diverse of exciting new physics. The band gap can be continuously reduced ascribed to the potential drop over the embedded TMD and the strain substantially affects the band gap nature. The true type-II alignment forms due to the coherent lattice and strong interface coupling suggesting the effective separation and collection of excitons. Interestingly, two-dimensional quantum wells of in-plane TMD can enrich the photoluminescence properties of TMD materials. The intrinsic electric polarization enhances the spin-orbital coupling and demonstrates the possibility to achieve topological insulator state and valleytronics in TMD quantum wells. In-plane TMD quantum wells have opened up new possibilities of applications in next-generation devices at nanoscale.

No MeSH data available.


Related in: MedlinePlus

VBM and CBM at the A-point for WS2/MoSe2/WS2 quantum well with different MoSe2 thickness of n = 1–4.(a,c,e,g) represent the VBM, while (b,d,f,h) indicate the CBM. The small spheres are non-metal atoms (S and Se), while big spheres are metal atoms (Mo and W).
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f4: VBM and CBM at the A-point for WS2/MoSe2/WS2 quantum well with different MoSe2 thickness of n = 1–4.(a,c,e,g) represent the VBM, while (b,d,f,h) indicate the CBM. The small spheres are non-metal atoms (S and Se), while big spheres are metal atoms (Mo and W).

Mentions: In case of WS2/MoSe2/WS2 quantum well, both VBM and CBM are predominantly distributed on embedded MoSe2, as shown in Fig. 4. As the MoSe2 thickness increases, the VBM and CBM tend to separate each other to locate at opposite sides of MoSe2 due to the intrinsic electric field, reducing the band gap. However, the separation reduces the recombination efficiency and thus affects the application in light emitting. In addition, charge transfer gives rise to band bending in constituent TMDs and strain-induced piezoelectric polarization results in quantum-confined Stark effect. As a result, further works are in need to omit these factors by, for example, carrier doping, to well confine the carriers in the wells.


Controlling the Electronic Structures and Properties of in-Plane Transition-Metal Dichalcogenides Quantum Wells.

Wei W, Dai Y, Niu C, Huang B - Sci Rep (2015)

VBM and CBM at the A-point for WS2/MoSe2/WS2 quantum well with different MoSe2 thickness of n = 1–4.(a,c,e,g) represent the VBM, while (b,d,f,h) indicate the CBM. The small spheres are non-metal atoms (S and Se), while big spheres are metal atoms (Mo and W).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663467&req=5

f4: VBM and CBM at the A-point for WS2/MoSe2/WS2 quantum well with different MoSe2 thickness of n = 1–4.(a,c,e,g) represent the VBM, while (b,d,f,h) indicate the CBM. The small spheres are non-metal atoms (S and Se), while big spheres are metal atoms (Mo and W).
Mentions: In case of WS2/MoSe2/WS2 quantum well, both VBM and CBM are predominantly distributed on embedded MoSe2, as shown in Fig. 4. As the MoSe2 thickness increases, the VBM and CBM tend to separate each other to locate at opposite sides of MoSe2 due to the intrinsic electric field, reducing the band gap. However, the separation reduces the recombination efficiency and thus affects the application in light emitting. In addition, charge transfer gives rise to band bending in constituent TMDs and strain-induced piezoelectric polarization results in quantum-confined Stark effect. As a result, further works are in need to omit these factors by, for example, carrier doping, to well confine the carriers in the wells.

Bottom Line: The true type-II alignment forms due to the coherent lattice and strong interface coupling suggesting the effective separation and collection of excitons.The intrinsic electric polarization enhances the spin-orbital coupling and demonstrates the possibility to achieve topological insulator state and valleytronics in TMD quantum wells.In-plane TMD quantum wells have opened up new possibilities of applications in next-generation devices at nanoscale.

View Article: PubMed Central - PubMed

Affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.

ABSTRACT
In-plane transition-metal dichalcogenides (TMDs) quantum wells have been studied on the basis of first-principles density functional calculations to reveal how to control the electronic structures and the properties. In collection of quantum confinement, strain and intrinsic electric field, TMD quantum wells offer a diverse of exciting new physics. The band gap can be continuously reduced ascribed to the potential drop over the embedded TMD and the strain substantially affects the band gap nature. The true type-II alignment forms due to the coherent lattice and strong interface coupling suggesting the effective separation and collection of excitons. Interestingly, two-dimensional quantum wells of in-plane TMD can enrich the photoluminescence properties of TMD materials. The intrinsic electric polarization enhances the spin-orbital coupling and demonstrates the possibility to achieve topological insulator state and valleytronics in TMD quantum wells. In-plane TMD quantum wells have opened up new possibilities of applications in next-generation devices at nanoscale.

No MeSH data available.


Related in: MedlinePlus