| Records |
| Author |
Bafekry, A.; Shojai, F.; Hoat, D.M.; Shahrokhi, M.; Ghergherehchi, M.; Nguyen, C. |
| Title |
The mechanical, electronic, optical and thermoelectric properties of two-dimensional honeycomb-like of XSb (X = Si, Ge, Sn) monolayers: a first-principles calculations |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Rsc Advances |
Abbreviated Journal |
Rsc Adv |
Volume  |
10 |
Issue |
51 |
Pages |
30398-30405 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Herein, by using first-principles calculations, we demonstrate a two-dimensional (2D) of XSb (X = Si, Ge, and Sn) monolayers that have a honey-like crystal structure. The structural, mechanical, electronic, thermoelectric efficiency, and optical properties of XSb monolayers are studied.Ab initiomolecular dynamic simulations and phonon dispersion calculations suggests their good thermal and dynamical stabilities. The mechanical properties of XSb monolayers shows that the monolayers are considerably softer than graphene, and their in-plane stiffness decreases from SiSb to SnSb. Our results shows that the single layers of SiSb, GeSb and SnSb are semiconductor with band gap of 1.48, 0.77 and 0.73 eV, respectively. The optical analysis illustrate that the first absorption peaks of the SiSb, GeSb and SnSb monolayers along the in-plane polarization are located in visible range of light which may serve as a promising candidate to design advanced optoelectronic devices. Thermoelectric properties of the XSb monolayers, including Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor and figure of merit are calculated as a function of doping level at temperatures of 300 K and 800 K. Between the studied two-dimensional materials (2DM), SiSb single layer may be the most promising candidate for application in the thermoelectric generators. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000561344000009 |
Publication Date |
2020-08-17 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2046-2069 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.9 |
Times cited |
2 |
Open Access |
|
| Notes |
; This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2017R1A2B2011989). ; |
Approved |
Most recent IF: 3.9; 2020 IF: 3.108 |
| Call Number |
UA @ admin @ c:irua:172074 |
Serial |
6624 |
| Permanent link to this record |
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| Author |
Bafekry, A.; Shojaei, F.; Obeid, M.M.; Ghergherehchi, M.; Nguyen, C.; Oskouian, M. |
| Title |
Two-dimensional silicon bismotide (SiBi) monolayer with a honeycomb-like lattice: first-principles study of tuning the electronic properties |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Rsc Advances |
Abbreviated Journal |
Rsc Adv |
| Volume |
10 |
Issue |
53 |
Pages |
31894-31900 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Using density functional theory, we investigate a novel two-dimensional silicon bismotide (SiBi) that has a layered GaSe-like crystal structure.Ab initiomolecular dynamic simulations and phonon dispersion calculations suggest its good thermal and dynamical stability. The SiBi monolayer is a semiconductor with a narrow indirect bandgap of 0.4 eV. Our results show that the indirect bandgap decreases as the number of layers increases, and when the number of layers is more than six layers, direct-to-indirect bandgap switching occurs. The SiBi bilayer is found to be very sensitive to an E-field. The bandgap monotonically decreases in response to uniaxial and biaxial compressive strain, and reaches 0.2 eV at 5%, while at 6%, the semiconductor becomes a metal. For both uniaxial and biaxial tensile strains, the material remains a semiconductor and indirect-to-direct bandgap transition occurs at a strain of 3%. Compared to a SiBi monolayer with a layer thickness of 4.89 angstrom, the bandgap decreases with either increasing or decreasing layer thickness, and at a thicknesses of 4.59 to 5.01 angstrom, the semiconductor-to-metal transition happens. In addition, under pressure, the semiconducting character of the SiBi bilayer with a 0.25 eV direct bandgap is preserved. Our results demonstrate that the SiBi nanosheet is a promising candidate for designing high-speed low-dissipation devices. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000565206400027 |
Publication Date |
2020-09-02 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
|
| ISSN |
2046-2069 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.9 |
Times cited |
8 |
Open Access |
|
| Notes |
; This work was supported by the National Research Foundation of Korea (NRF) grant, funded by the Korea government (MSIT) (NRF-2017R1A2B2011989). ; |
Approved |
Most recent IF: 3.9; 2020 IF: 3.108 |
| Call Number |
UA @ admin @ c:irua:172045 |
Serial |
6644 |
| Permanent link to this record |
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| |
| Author |
Bafekry, A.; Obeid, M.; Nguyen, C.; Bagheri Tagani, M.; Ghergherehchi, M. |
| Title |
Graphene hetero-multilayer on layered platinum mineral Jacutingaite (Pt₂HgSe₃): Van der Waals heterostructures with novel optoelectronic and thermoelectric performances |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Materials Chemistry A |
Abbreviated Journal |
J Mater Chem A |
| Volume |
8 |
Issue |
26 |
Pages |
13248-13260 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
| Abstract |
Motivated by the recent successful synthesis of the layered platinum mineral jacutingaite (Pt2HgSe3), we have studied the optoelectronic, mechanical, and thermoelectric properties of graphene hetero-multilayer on Pt(2)HgSe(3)monolayer (PHS) heterostructures (LG/PHS) by using first-principles calculations. PHS is a topological insulator with a band gap of about 160 meV with fully relativistic calculations; when graphene layers are stacked on PHS, a narrow band gap of similar to 10-15 meV opens. In the presence of gate-voltage and out-of plane strain,i.e.pressure, the electronic properties are modified; the Dirac-cone of graphene can be shifted upwards (downward) to a lower (higher) binding energy. The absorption spectrum shows two peaks, which are located around 216 nm (5.74 eV) and protracted to 490 nm (2.53 eV), indicating that PHS could absorb more visible light. Increasing the number of graphene layers on PHS has a positive impact on the UV-vis light absorption and gives a clear red-shift with enhanced absorption intensity. To investigate the electronic performance of the heterostructure, the electrical conductance and thermopower of a device composed of graphene layers and PHS is examined by a combination of DFT and Green function formalism. The number of graphene layers can significantly tune the thermopower and electrical conductance. This analysis reveals that the heterostructures not only significantly affect the electronic properties, but they can also be used as an efficient way to modulate the optic and thermoelectric properties. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000546391600032 |
Publication Date |
2020-05-28 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
|
Edition |
|
| ISSN |
2050-7488; 2050-7496 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
11.9 |
Times cited |
20 |
Open Access |
|
| Notes |
; This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIT) (NRF-2017R1A2B2011989) and Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 103.01-2019.05. ; |
Approved |
Most recent IF: 11.9; 2020 IF: 8.867 |
| Call Number |
UA @ admin @ c:irua:169755 |
Serial |
6529 |
| Permanent link to this record |
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| Author |
Bafekry, A.; Shahrokhi, M.; Shafique, A.; Jappor, H.R.; Fadlallah, M.M.; Stampfl, C.; Ghergherehchi, M.; Mushtaq, M.; Feghhi, S.A.H.; Gogova, D. |
| Title |
Semiconducting chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula with outstanding properties : a first-principles calculation study |
Type |
A1 Journal article |
| Year |
2021 |
Publication |
ACS Omega |
Abbreviated Journal |
|
| Volume |
6 |
Issue |
14 |
Pages |
9433-9441 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Very recently, a new class of the multicationic and -anionic entropy-stabilized chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula has been successfully fabricated and characterized experimentally [Zihao Deng et al., Chem. Mater. 32, 6070 (2020)]. Motivated by the recent experiment, herein, we perform density functional theory-based first-principles calculations in order to investigate the structural, mechanical, electronic, optical, and thermoelectric properties. The calculations of the cohesive energy and elasticity parameters indicate that the alloy is stable. Also, the mechanical study shows that the alloy has a brittle nature. The GeSnPbSSeTe alloy is a semiconductor with a direct band gap of 0.4 eV (0.3 eV using spin-orbit coupling effect). The optical analysis illustrates that the first peak of Im(epsilon) for the GeSnPbSSeTe alloy along all polarization directions is located in the visible range of the spectrum which renders it a promising material for applications in optical and electronic devices. Interestingly, we find an optically anisotropic character of this system which is highly desirable for the design of polarization-sensitive photodetectors. We have accurately predicted the thermoelectric coefficients and have calculated a large power factor value of 3.7 x 10(11) W m(-1) K-2 s(-1) for p-type. The high p-type power factor is originated from the multiple valleys near the valence band maxima. The anisotropic results of the optical and transport properties are related to the specific tetragonal alloy unit cell. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000640649500012 |
Publication Date |
2021-03-30 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
| Notes |
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Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:178395 |
Serial |
7017 |
| Permanent link to this record |
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| Author |
Bafekry, A.; Stampfl, C.; Ghergherehchi, M. |
| Title |
Strain, electric-field and functionalization induced widely tunable electronic properties in MoS2/BC3, /C3N and / C3N4 van der Waals heterostructures |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Nanotechnology (Bristol. Print) |
Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
295202 pp |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
| Abstract |
In this paper, the effect of BC3, C3N and C3N4BC(3) and MoS2/C(3)N4 heterostructures are direct semiconductors with band gaps of 0.4 and 1.74 eV, respectively, while MoS2/C3N is a metal. Furthermore, the influence of strain and electric field on the electronic structure of these van der Waals heterostructures is investigated. The MoS2/BC3 heterostructure, for strains larger than -4%, transforms it into a metal where the metallic character is maintained for strains larger than -6%. The band gap decreases with increasing strain to 0.35 eV (at +2%), while for strain (>+6%) a direct-indirect band gap transition is predicted to occur. For the MoS2/C3N heterostructure, the metallic character persists for all strains considered. On applying an electric field, the electronic properties of MoS2/C3N4 are modified and its band gap decreases as the electric field increases. Interestingly, the band gap reaches 30 meV at +0.8 V/angstrom, and with increase above +0.8 V/angstrom, a semiconductor-to-metal transition occurs. Furthermore, we investigated effects of semi- and full-hydrogenation of MoS2/C3N and we found that it leads to a metallic and semiconducting character, respectively. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000532366000001 |
Publication Date |
2020-04-09 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
|
ISBN |
0957-4484 |
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
19 |
Open Access |
|
| Notes |
; This work has supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(NRF-2017R1A2B2011989). ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:169523 |
Serial |
6444 |
| Permanent link to this record |
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| Author |
Bafekry, A.; Van Nguyen, C.; Stampfl, C.; Akgenc, B.; Ghergherehchi, M. |
| Title |
Oxygen vacancies in the single layer of Ti₂CO₂ MXene: effects of gating voltage, mechanical strain, and atomic impurities |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physica Status Solidi B-Basic Solid State Physics |
Abbreviated Journal |
Phys Status Solidi B |
| Volume |
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Issue |
|
Pages |
2000343-2000349 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Herein, using first-principles calculations the structural and electronic properties of the Ti(2)CO(2)MXene monolayer with and without oxygen vacancies are systematically investigated with different defect concentrations and patterns, including partial, linear, local, and hexagonal types. The Ti(2)CO(2)monolayer is found to be a semiconductor with a bandgap of 0.35 eV. The introduction of oxygen vacancies tends to increase the bandgap and leads to electronic phase transitions from nonmagnetic semiconductors to half-metals. Moreover, the semiconducting characteristic of O-vacancy Ti(2)CO(2)can be adjusted via electric fields, strain, and F-atom substitution. In particular, an electric field can be used to alter the nonmagnetic semiconductor of O-vacancy Ti(2)CO(2)into a magnetic one or into a half-metal, whereas the electronic phase transition from a semiconductor to metal can be achieved by applying strain and F-atom substitution. The results provide a useful guide for practical applications of O-vacancy Ti(2)CO(2)monolayers in nanoelectronic and spinstronic nanodevices. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000571060800001 |
Publication Date |
2020-09-04 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0370-1972 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.6 |
Times cited |
|
Open Access |
|
| Notes |
; This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (NRF-2017R1A2B2011989). ; |
Approved |
Most recent IF: 1.6; 2020 IF: 1.674 |
| Call Number |
UA @ admin @ c:irua:171948 |
Serial |
6576 |
| Permanent link to this record |
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| Author |
Bafekry, A.; Yagmurcukardes, M.; Akgenc, B.; Ghergherehchi, M.; Nguyen, C. |
| Title |
Van der Waals heterostructures of MoS₂ and Janus MoSSe monolayers on graphitic boron-carbon-nitride (BC₃, C₃N, C₃N₄ and C₄N₃) nanosheets: a first-principles study |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Physics D-Applied Physics |
Abbreviated Journal |
J Phys D Appl Phys |
| Volume |
|
Issue |
|
Pages |
1-10 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
In this work, we extensively investigate the structural and electronic properties of van der Waals heterostructures (HTs) constructed by MoS${2}$/$BC3$, MoS${2}$/$C3N$, MoS${2}$/$C3N4$, MoS${2}$/$C4N3$ and those using Janus MoSSe instead of MoS$2$ by performing density functional theory calculations. The electronic band structure calculations and the corresponding partial density of states reveal that the significant changes are driven by quite strong layer-layer interaction between the constitutive layers. Our results show that although all monolayers are semiconductors as free-standing layers, the MoS${2}$/$C3N$ and MoS${2}$/$C4N3$ bilayer HTs display metallic behavior as a consequence of transfer of charge carriers between two constituent layers. In addition, it is found that in MoSSe/$C3N$ bilayer HT, the degree of metallicity is affected by the interface chalcogen atom type when Se atoms are facing to $C3N$ layer, the overlap of the bands around the Fermi level is smaller. Moreover, the half-metallic magnetic $C4N3$ is shown to form magnetic half-metallic trilayer HT with MoS$2$ independent of the stacking sequence, i.e. whether it is sandwiched or two $C4N3$ layer encapsulate MoS$2$ layer. We further analyze the trilayer HTs in which MoS$2$ is encapsulated by two different monolayers and it is revealed that at least with one magnetic monolayer, it is possible to construct a magnetic trilayer. While the trilayer of $C4N3$/MoS${2}$/$BC3$ and $C4N3$/MoS${2}$/$C3N4$ exhibit half-metallic characteristics, $C4N3$/MoS${_2}$/$C3$N possesses a magnetic metallic ground state. Overall, our results reveal that holly structures of BCN crystals are suitable for heterostructure formation even over van der Waals type interaction which significantly changes electronic nature of the constituent layers. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000543344800001 |
Publication Date |
2020-04-07 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
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Edition |
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| ISSN |
0022-3727 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
|
Open Access |
|
| Notes |
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Approved |
Most recent IF: 3.4; 2020 IF: 2.588 |
| Call Number |
UA @ admin @ c:irua:169754 |
Serial |
6651 |
| Permanent link to this record |
