Electro-absorption of silicene and bilayer graphene quantum dots

Abdelsalam, Hazem; Talaat, Mohamed; Luk’yanchuk, I.; Portnoi, M. E.; Saroka, V. A.

doi:10.1063/1.4955222

Cited by 39 publications

(30 citation statements)

References 47 publications

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“…These states are absent in graphene dots of similar shape and are attributed to the puckered structure of phosphorene. Similar states exist only in triangular graphene and silicene counterparts with zigzag edges [42,72]. We found that for each type of phosphorene dot with regular edges the number of these peculiar states is related to the dot size indexed by the number of hexagonal elements at one edge, see Table III.…”

Section: Discussionmentioning

confidence: 63%

Electro-optical properties of phosphorene quantum dots

et al. 2017

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We study electronic and optical properties of single layer phosphorene quantum dots with various shapes, sizes, and edge types (including disordered edges) subjected to an external electric field normal to the structure plane. Compared to graphene quantum dots, in phosphorene clusters of similar shape and size there is a set of edge states with energies dispersed at around the Fermi level. These states make the majority of phosphorene quantum dots metallic and enrich the phosphorene absorption gap with low-energy absorption peaks tunable by the electric field. The presence of the edge states dispersed at around the Fermi level is a characteristic feature that is independent of the edge morphology and roughness.

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Section: Discussionmentioning

confidence: 63%

Electro-optical properties of phosphorene quantum dots

et al. 2017

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“…ZES appear in triangle GQDs while DES appear in other shapes such as hexagonal and circular GQDs. Due to the inclusion of electron-electron interactions in the density functional theory (DFT) calculations, a tiny energy gap is opened between ZES [2,6,9]. In general, TB or DFT calculations confirmed the appearance of edge states in GQDs.…”

Section: -Introductionmentioning

confidence: 99%

“…Flake-like graphene quantum dots (GQDs) have attracted great attention due to their unique electronic [1][2][3][4][5] and optical [6][7][8][9][10] properties. The distinguishable properties of GQDs arise from the electron confinement in the finite size graphene cluster that leads to the opening of energy gap and quantization of electronic energy levels.…”

Section: -Introductionmentioning

confidence: 99%

First principles study of edge carboxylated graphene quantum dots

Abdelsalam

Elhaes

Ibrahim

2018

Physica B: Condensed Matter

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The structure stability and electronic properties of edge carboxylated hexagonal and triangular graphene quantum dots are investigated by using density functional theory. The calculated binding energies show that the hexagonal clusters with armchair edges have the highest stability among all other flakes. The binding energy of carboxylated graphene quantum dots increases by increasing the number of attached carboxyl groups. Our study shows that the total dipole moment significantly increases by adding COOH with the highest values observed in triangular clusters. The edge states in triangular graphene with zigzag edges produce completely different energy spectrum from other shapes as (a) the energy gap in triangular zigzag cluster is very small compared to other clusters and (b) the highest occupied molecular orbital is localized at the edges which is in contrast to other clusters where it is distributed over the cluster surface. The enhanced reactivity and the controllable energy gap by shape and edge termination make graphene quantum dots ideal nanodevices for various applications such as sensors. The infrared spectra for different flakes are presented for confirmation and detection of the obtained results.

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“…In what follows we consider only quasi-metallic AGNRs, for which the edge effects lead to more prominent interband transitions between the closest valence and conduction subbands than for ZGNRs [16](triangular bilayer graphene clusters with zigzag edges also have weak interband transitions between the edge states [17]). The band structure of AGNRs can be obtained from that of graphene by a technique similar to that used for dealing with CNTs.…”

Section: Graphene Nanoribbonsmentioning

confidence: 99%

Terahertz transitions in carbon nanotubes and graphene nanoribbons

Saroka

Hartmann

Portnoi

2017

2017 International Conference on Electromagnetics in Advanced Applications (ICEAA)

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-Interband dipole transitions are calculated in quasi-metallic single-walled carbon nanotubes and armchair graphene nanoribbons. It is shown that the curvature effects for tubes and the edge effects for ribbons result not only in a small band gap opening, corresponding to THz frequencies, but also in a significant enhancement of the transition probability rate across the band gap. This makes these nanostructures perspective canditates for sources and detectors of THz radiation.

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Electro-absorption of silicene and bilayer graphene quantum dots

Cited by 39 publications

References 47 publications

Electro-optical properties of phosphorene quantum dots

Electro-optical properties of phosphorene quantum dots

First principles study of edge carboxylated graphene quantum dots

Terahertz transitions in carbon nanotubes and graphene nanoribbons

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