Indirect–direct bandgap transition and gap width tuning in bilayer MoS 2 superlattices

Jiang, Junke; Xiu, Shu; Zheng, Mengmeng; Jia, Tian Tian; Liu, H.Y.; Zhang, Y.; Chen, G.

doi:10.1016/j.cplett.2014.08.060

Cited by 23 publications

(13 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our example case, the rotation between the two MoS 2 layers is 0.8° with a Moiré periodicity of ~14 nm, as shown in Figure 5. Our DFT calculations (see Methods) confirm that AB stacking is energetically favored over AA 31 stacking and the AB-AA transition region, all of which are observed in the experimental image. Since these different stackings also have different equilibrium distances (by less than 0.6 Å), it is reasonable to expect that one or both of the overlapping layers have an undulating structure.…”

Section: Resultssupporting

confidence: 70%

“…In our example case, the rotation between the two MoS 2 layers is 0.8° with a Moiré periodicity of ~14 nm, as shown in Figure 5. Our DFT calculations (see Methods) confirm that AB stacking is energetically favored over AA 31 Due to the sensitivity of the electronic properties of MoS 2 to the stacking order (see Supplementary Material) and external influences 32 , this allows at least in principle tuning those properties by controlling the misorientation of the overlapping grains.…”

Section: Resultsmentioning

confidence: 59%

“…Using a plane-wave basis (cutoff energy 700 eV, 16×16×1 k-point mesh) we relaxed the atomic positions using the C09 van der Waals functional 36 (we tested other exchange correlation functionals but this one seemed to give the best agreement with Refs. 31,37 ) so that maximum forces were below 0.01 eV/Å. Comparing the total energies (E) for each stacking order, we found E AB , E AA , and E AA-AB to be 22.926 eV, 22.971 eV and 22.969 eV, respectively.…”

Section: Methodsmentioning

confidence: 89%

See 2 more Smart Citations

Grain boundary-mediated nanopores in molybdenum disulfide grown by chemical vapor deposition

et al. 2017

View full text Add to dashboard Cite

Molybdenum disulfide (MoS) is a particularly interesting member of the family of two-dimensional (2D) materials due to its semiconducting and tunable electronic properties. Currently, the most reliable method for obtaining high-quality industrial scale amounts of 2D materials is chemical vapor deposition (CVD), which results in polycrystalline samples. As grain boundaries (GBs) are intrinsic defect lines within CVD-grown 2D materials, their atomic structure is of paramount importance. Here, through atomic-scale analysis of micrometer-long GBs, we show that covalently bound boundaries in 2D MoS tend to be decorated by nanopores. Such boundaries occur when differently oriented MoS grains merge during growth, whereas the overlap of grains leads to boundaries with bilayer areas. Our results suggest that the nanopore formation is related to stress release in areas with a high concentration of dislocation cores at the grain boundaries, and that the interlayer interaction leads to intrinsic rippling at the overlap regions. This provides insights for the controlled fabrication of large-scale MoS samples with desired structural properties for applications.

show abstract

Section: Resultssupporting

confidence: 70%

“…In our example case, the rotation between the two MoS 2 layers is 0.8° with a Moiré periodicity of ~14 nm, as shown in Figure 5. Our DFT calculations (see Methods) confirm that AB stacking is energetically favored over AA 31 Due to the sensitivity of the electronic properties of MoS 2 to the stacking order (see Supplementary Material) and external influences 32 , this allows at least in principle tuning those properties by controlling the misorientation of the overlapping grains.…”

Section: Resultsmentioning

confidence: 59%

Section: Methodsmentioning

confidence: 89%

See 1 more Smart Citation

Grain boundary-mediated nanopores in molybdenum disulfide grown by chemical vapor deposition

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The inversion symmetry preserved (ISP) defect has been found to open bandgap in the 3 p silicene nanomeshes, which would however not alter the conducting properties of the 3 p + 1 and 3 p + 2 nanomeshes 19 20 21 22 . The periodically arranged defects would impose new Born von Karman boundary conditions on silience to make it into superlattice 24 25 , which have been introduced in by the modulation of the Bravais lattice. In the defect free pristine silicene crystal, the hexagonal primitive unit cell defined by a × b (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Silicene nanomeshes: bandgap opening by bond symmetry breaking and uniaxial strain

Jia

Fan

Zheng

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Based on the first-principles calculations, we have investigated in detail the bandgap opening of silicene nanomeshes. Different to the mechanism of bandgap opening induced by the sublattice equivalence breaking, the method of degenerate perturbation through breaking the bond symmetry could split the π-like bands in the inversion symmetry preserved silicene nanomeshes, resulting into the πa1 − πa2 and πz1 − πz2 band sets with sizable energy intervals. Besides the bandgap opening in the nanomeshes with Dirac point being folded to Γ point, the split energy intervals are however apart away from Fermi level to leave the semimetal nature unchanged for the other nanomeshes with Dirac points located at opposite sides of Γ point as opposite pseudo spin wave valleys. A mass bandgap could be then opened at the aid of uniaxial strain to transfer the nanomesh to be semiconducting, whose width could be continuously enlarged until reaching its maximum Emax. Moreover, the Emax could also be tuned by controlling the defect density in silicene nanomeshes. These studies could contribute to the understanding of the bandgap engineering of silicene-based nanomaterials to call for further investigations on both theory and experiment.

show abstract

“…These progresses in fabricating advanced nanomaterials suggest the possibilities in preparing graphene nanomeshes in experiment with nice precision. In fact, this could be regarded as to pattern graphene into superlattice with carbon vacancies, which would modulate the corresponding Born-von Karman boundary conditions 24 25 26 . As shown in the experimental studies 20 21 22 23 , the antidot with circular vacancy hole may be easily realized, which preserves the inversion symmetry.…”

mentioning

confidence: 99%

Dirac cone move and bandgap on/off switching of graphene superlattice

Jia

Zheng

Fan

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Using the density functional theory with generalized gradient approximation, we have studied in detail the cooperative effects of degenerate perturbation and uniaxial strain on bandgap opening in graphene. The uniaxial strain could split π bands into πa and πz bands with an energy interval Es to move the Dirac cone. The inversion symmetry preserved antidot would then further split the πa (πz) bands into πa1 (πz1) and πa2 (πz2) bands with an energy interval Ed, which accounts for the bandgap opening in a kind of superlattices with Dirac cone being folded to Γ point. However, such antidot would not affect the semimetal nature of the other superlattices, showing a novel mechanism for bandstructure engineering as compared to the sublattice-equivalence breaking. For a superlattice with bandgap of ~Ed opened at Γ point, the Es could be increased by strengthening strain to close the bandgap, suggesting a reversible switch between the high velocity properties of massless Fermions attributed to the linear dispersion relation around Dirac cone and the high on/off ratio properties associated with the sizable bandgap. Moreover, the gap width actually could be continuously tuned by controlling the strain, showing attractive application potentials.

show abstract

Indirect–direct bandgap transition and gap width tuning in bilayer MoS 2 superlattices

Cited by 23 publications

References 24 publications

Grain boundary-mediated nanopores in molybdenum disulfide grown by chemical vapor deposition

Grain boundary-mediated nanopores in molybdenum disulfide grown by chemical vapor deposition

Silicene nanomeshes: bandgap opening by bond symmetry breaking and uniaxial strain

Dirac cone move and bandgap on/off switching of graphene superlattice

Contact Info

Product

Resources

About