Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Liang, Dong; Namburu, Raju R.; O’Regan, Terrance; Dubey, Madan; Dongare, Avinash M.

doi:10.1007/s10853-014-8370-5

Cited by 70 publications

(47 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This effect is caused by an increase in the energy level of the indirect valley at the Σ point as well as a corresponding decrease in the energy level of the direct valley at the K point 7 . While it is important to note these results are obtained under uniaxial strain, similar trends between uniaxial and biaxial strain have been observed in theoretical studies on other 2D material systems 29 . Figure 4c depicts the PL spectra of as-grown, exfoliated and transferred bilayer WSe 2 .…”

Section: Resultssupporting

confidence: 84%

Strain-engineered growth of two-dimensional materials

et al. 2017

Self Cite

View full text Add to dashboard Cite

The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe2, respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.

show abstract

Section: Resultssupporting

confidence: 84%

Strain-engineered growth of two-dimensional materials

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…44,45 Our results are consistent with previous theoretical study performed by Yun et al 46 which was shown that strain makes band gap of monolayer dichalcogenides indirect. 44,45 Our results are consistent with previous theoretical study performed by Yun et al 46 which was shown that strain makes band gap of monolayer dichalcogenides indirect.…”

Section: Charge Transfer Analysissupporting

confidence: 92%

Band engineering and charge separation in the Mo_1−xW_xS₂/TiO₂heterostructure by alloying: first principle prediction

et al. 2015

View full text Add to dashboard Cite

The composition dependent electronic properties of the Mo 1Àx W x S 2 monolayer deposited over a TiO 2 (110) substrate were investigated based on ab initio density functional calculations by applying periodic boundary conditions. Adsorption of the Mo 1Àx W x S 2 monolayer on the TiO 2 is physical in nature based on calculated binding energy values. It was found that the mechanical strain generated by the presence of TiO 2 beneath the Mo 1Àx W x S 2 layer resulted in a shift in band position of the Mo 1Àx W x S 2 in favor of photoelectrochemical water splitting. Moreover, variation of W concentration in Mo 1Àx W x S 2 could improve the charge separation and increase the effective mass ratio leading to an extension of the electron-hole pair lifetime which is useful for photocatalytic and photoelectrochemical applications. † Electronic supplementary information (ESI) available: 2D proles of charge density difference, experimental and optimized lattice constants of TiO 2 and MS 2 (M ¼ Mo, W) and optimized atomic coordinates of Mo 1Àx W x S 2 /TiO 2 (110) and Mo 1Àx W x S 2 . See

show abstract

“…Similarly, bandgap engineering is possible by applying strain. The application of strain drives a direct-to-indirect band gap transition in single-layer MoS 2 [27,28,29,30,31,32]. Moreover, suitable hydrostatic pressure reduces the band gap of single-and multi-layer MoS 2 resulting in a phase transition from semiconductor to metal [33,34].…”

Section: Introductionmentioning

confidence: 99%

Vibrational and optical properties of MoS2: From monolayer to bulk

Molina-Sánchez

Hummer

Wirtz

2015

Surface Science Reports

206

167

View full text Add to dashboard Cite

Molybdenum disulfide, MoS 2 , has recently gained considerable attention as a layered material where neighboring layers are only weakly interacting and can easily slide against each other. Therefore, mechanical exfoliation allows the fabrication of single and multi-layers and opens the possibility to generate atomically thin crystals with outstanding properties. In contrast to graphene, it has an optical gap of 1.9 eV. This makes it a prominent candidate for transistor and opto-electronic applications. Single-layer MoS 2 exhibits remarkably different physical properties compared to bulk MoS 2 due to the absence of interlayer hybridization. For instance, while the band gap of bulk and multi-layer MoS 2 is indirect, it becomes direct with decreasing number of layers. In this review, we analyze from a theoretical point of view the electronic, optical, and vibrational properties of single-layer, few-layer and bulk MoS 2 . In particular, we focus on the effects of spinorbit interaction, number of layers, and applied tensile strain on the vibrational and optical properties. We examine the results obtained by different methodologies, mainly ab initio approaches. We also discuss which approximations are suitable for MoS 2 and layered materials. The effect of external strain on the band gap of single-layer MoS 2 and the crossover from indirect to direct band gap is investigated. We analyze the excitonic effects on the absorption spectra. The main features, such as the double peak at the absorption threshold and the high-energy exciton are presented. Furthermore, we report on the phonon dispersion relations of single-layer, few-layer and bulk MoS 2 . Based on the latter, we explain the behavior of the Raman-active A 1g and E 1 2g modes as a function of the number of layers. Finally, we compare theoretical and experimental results of Raman, photoluminescence, and optical-absorption spectroscopy.

show abstract

Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Cited by 70 publications

References 40 publications

Strain-engineered growth of two-dimensional materials

Strain-engineered growth of two-dimensional materials

Band engineering and charge separation in the Mo_1−xW_xS₂/TiO₂heterostructure by alloying: first principle prediction

Vibrational and optical properties of MoS2: From monolayer to bulk

Contact Info

Product

Resources

About

Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Cited by 70 publications

References 40 publications

Strain-engineered growth of two-dimensional materials

Strain-engineered growth of two-dimensional materials

Band engineering and charge separation in the Mo1−xWxS2/TiO2heterostructure by alloying: first principle prediction

Vibrational and optical properties of MoS2: From monolayer to bulk

Contact Info

Product

Resources

About

Band engineering and charge separation in the Mo_1−xW_xS₂/TiO₂heterostructure by alloying: first principle prediction