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Author |
Xiao, H.; Zhang, Z.; Xu, W.; Wang, Q.; Xiao, Y.; Ding, L.; Huang, J.; Li, H.; He, B.; Peeters, F.M. |
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Title |
Terahertz optoelectronic properties of synthetic single crystal diamond |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Diamond and related materials |
Abbreviated Journal |
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Volume |
139 |
Issue  |
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Pages |
110266-110268 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A systematic investigation is undertaken for studying the optoelectronic properties of single crystal diamond (SCD) grown by microwave plasma chemical vapor deposition (MPCVD). It is indicated that, without intentional doping and surface treatment during the sample growth, the terahertz (THz) optical conduction in SCD is mainly affected by surface H-terminations, -OH-, O- and N-based functional groups. By using THz time-domain spectroscopy (TDS), we measure the transmittance, the complex dielectric constant and optical conductivity σ(ω) of SCD. We find that SCD does not show typical semiconductor characteristics in THz regime, where σ(ω) cannot be described rightly by the conventional Drude formula. Via fitting the real and imaginary parts of σ(ω) to the Drude-Smith formula, the ratio of the average carrier density to the effective electron mass γ = ne/m*, the electronic relaxation time τ and the electronic backscattering or localization factor can be determined optically. The temperature dependence of these parameters is examined. From the temperature dependence of γ, a metallic to semiconductor transition is observed at about T = 10 K. The temperature dependence of τ is mainly induced by electron coupling with acoustic-phonons and there is a significant effect of photon-induced electron backscattering or localization in SCD. This work demonstrates that THz TDS is a powerful technique in studying SCD which contains H-, N- and O-based bonds and has low electron density and high dc resistivity. The results obtained from this study can benefit us to gain an in-depth understanding of SCD and may provide new guidance for the application of SCD as electronic, optical and optoelectronic materials. |
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Wos |
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Publication Date |
2023-08-02 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0925-9635 |
ISBN |
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Additional Links |
UA library record |
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Impact Factor |
4.1 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 4.1; 2023 IF: 2.561 |
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Call Number |
UA @ admin @ c:irua:200920 |
Serial |
9103 |
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Author |
Ozdemir, I.; Arkin, H.; Milošević, M.V.; V. Barth, J.; Aktuerk, E. |
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Title |
Exploring the adsorption mechanisms of neurotransmitter and amino acid on Ti3C2-MXene monolayer : insights from DFT calculations |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Surfaces and interfaces |
Abbreviated Journal |
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Volume |
46 |
Issue |
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Pages |
104169-9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In this study, we conducted a systematic density functional theory (DFT) investigation of the interaction between Ti3C2-MXene monolayer and biological molecules dopamine (DA) and serine (Ser) as neurotransmitter and amino acid, respectively. Our calculations show good agreement with previous literature findings for the optimized Ti3C2 monolayer. We found that DA and Ser molecules bind to the Ti3C2 surface with adsorption energies of -2.244 eV and -3.960 eV, respectively. The adsorption of Ser resulted in the dissociation of one H atom. Electronic density of states analyses revealed little changes in the electronic properties of the Ti3C2-MXene monolayer upon adsorption of the biomolecules. We further investigated the interaction of DA and Ser with Ti3C2 monolayers featuring surface -termination with OH functional group, and Ti -vacancy. Our calculations indicate that the adsorption energies significantly decrease in the presence of surface termination, with adsorption energies of -0.097 eV and -0.330 eV for DA and Ser, respectively. Adsorption energies on the Ti -vacancy surface, on the other hand, are calculated to be -3.584 eV and -3.856 eV for DA and Ser, respectively. Our results provide insights into the adsorption behavior of biological molecules on Ti3C2-MXene, demonstrating the potential of this material for biosensing and other biomedical applications. These findings highlight the importance of surface modifications in the development of functional materials and devices based on Ti3C2-MXene, and pave the way for future investigations into the use of 2D materials for biomedical applications. |
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001206950300001 |
Publication Date |
2024-03-08 |
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ISSN |
2468-0230 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
6.2 |
Times cited |
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Open Access |
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Notes |
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Most recent IF: 6.2; 2024 IF: NA |
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Call Number |
UA @ admin @ c:irua:205977 |
Serial |
9150 |
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Author |
Zhou, S.; Zhang, C.; Xu, W.; Zhang, J.; Xiao, Y.; Ding, L.; Wen, H.; Cheng, X.; Hu, C.; Li, H.; Li, X.; Peeters, F.M. |
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Title |
Observation of temperature induced phase transitions in TiO superconducting thin film via infrared measurement |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Infrared physics and technology |
Abbreviated Journal |
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Volume |
137 |
Issue |
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Pages |
105160-105169 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In contrast to conventional polycrystalline titanium oxide (TiO), it was found recently that the superconducting transition temperature Tc can be significantly enhanced from about 2 K to 7.4 K in cubic TiO thin films grown epitaxially on alpha-Al2O3 substrates. This kind of TiO film is also expected to have distinctive optoelectronic properties, which are still not very clear up to now. Herein, by using infrared (IR) reflection measurement we investigate the temperature-dependent optoelectronic response of a cubic TiO thin film, in which temperature induced phase transitions are observed. The semiconductor-, metallic- and semiconductor-like electronic phases of this superconducting film are found in the temperature regimes from 10 to 110 K, 110 to 220 K and above 220 K, respectively. The results obtained optically are consistent with those measured by transport experiment. Furthermore, based on an improved reflection model developed here, we extract the complex optical conductivity of the cubic TiO thin film. We are able to approximately determine the characteristic parameters (e.g., effective electron mass, carrier density, scattering time, etc.) for different electronic phases by fitting the optical conductivity with the modified Lorentz formula. These results not only deepen our understanding of the fundamental physics for cubic TiO thin films but also may find applications in optoelectronic devices based on superconductors. |
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Wos |
001170490200001 |
Publication Date |
2024-01-21 |
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Edition |
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ISSN |
1350-4495 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.3 |
Times cited |
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Open Access |
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Notes |
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Most recent IF: 3.3; 2024 IF: 1.713 |
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Call Number |
UA @ admin @ c:irua:204853 |
Serial |
9162 |
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Author |
Xiao, H.; Wen, H.; Xu, W.; Cheng, Y.; Zhang, J.; Cheng, X.; Xiao, Y.; Ding, L.; Li, H.; He, B.; Peeters, F.M. |
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Title |
Terahertz magneto-optical properties of Nitrogen-doped diamond |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Infrared physics and technology |
Abbreviated Journal |
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Volume |
138 |
Issue |
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Pages |
105237-105239 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Nitrogen-doped diamond (N-D) is one of the most important carbon-based electronic and optical materials. Here we study the terahertz (THz) magneto-optical (MO) properties of N-D grown by microwave plasma-enhanced chemical vapor deposition. The optical microscope, SEM, XRD, Raman spectrum, FTIR spectroscopy and XPS are used for the characterization of N-D samples. Applying THz time-domain spectroscopy (TDS), in combination with the polarization test and the presence of magnetic field in Faraday geometry, THz MO transmissions through N-D are measured from 0 to 8 T at 80 K. The complex right- and left-handed circular transmission coefficients and MO conductivities for N-D are obtained accordingly. Through fitting the experimental results with theoretical formulas of the dielectric constant and MO conductivities for an electron gas, we are able to determine magneto-optically the key electronic parameters of N-D, such as the static dielectric constant epsilon b, the electron density ne, the electronic relaxation time tau, the electronic localization factor alpha and, particularly, the effective electron mass m* obtained under non-resonant condition. The dependence of these parameters upon magnetic field is examined and analyzed. We find that the MO conductivities of N-D can be described rightly by the MO Drude-Smith formulas developed by us previously. It is shown that N-doping and the presence of the magnetic field can lead towards the larger epsilon b and heavier m* in diamond, while ne/tau/alpha in N-D decreases/increases/decreases with increasing magnetic field. The results obtained from this work are benefit to us in gaining an in-depth understanding of the electronic and optoelectronic properties of N-D. |
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Wos |
001200173100001 |
Publication Date |
2024-02-15 |
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Edition |
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ISSN |
1350-4495 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.3 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 3.3; 2024 IF: 1.713 |
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Call Number |
UA @ admin @ c:irua:205523 |
Serial |
9178 |
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Author |
Hassani, N.; Movafegh-Ghadirli, A.; Mahdavifar, Z.; Peeters, F.M.; Neek-Amal, M. |
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Title |
Two new members of the covalent organic frameworks family : crystalline 2D-oxocarbon and 3D-borocarbon structures |
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A1 Journal article |
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Year |
2024 |
Publication |
Computational materials science |
Abbreviated Journal |
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Volume |
241 |
Issue |
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Pages |
1-9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Oxocarbons, known for over two centuries, have recently revealed a long-awaited facet: two-dimensional crystalline structures. Employing an intelligent global optimization algorithm (IGOA) alongside densityfunctional calculations, we unearthed a quasi -flat oxocarbon (C 6 0 6 ), featuring an oxygen -decorated hole, and a novel 3D-borocarbon. Comparative analyses with recently synthesized isostructures, such as 2D -porous carbon nitride (C 6 N 6 ) and 2D -porous boroxine (B 6 0 6 ), highlight the unique attributes of these compounds. All structures share a common stoichiometry of X 6 Y 6 (which we call COF-66), where X = B, C, and Y = B, N, O (with X not equal Y), exhibiting a 2D -crystalline structure, except for borocarbon C 6 B 6 , which forms a 3D crystal. In our comprehensive study, we conducted a detailed exploration of the electronic structure of X 6 Y 6 compounds, scrutinizing their thermodynamic properties and systematically evaluating phonon stability criteria. With expansive surface areas, diverse pore sizes, biocompatibility, pi-conjugation, and distinctive photoelectric properties, these structures, belonging to the covalent organic framework (COF) family, present enticing prospects for fundamental research and hold potential for biosensing applications. |
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Wos |
001215960700001 |
Publication Date |
2024-04-23 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0927-0256 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.3 |
Times cited |
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Open Access |
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Notes |
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Most recent IF: 3.3; 2024 IF: 2.292 |
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Call Number |
UA @ admin @ c:irua:206005 |
Serial |
9179 |
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