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| 2. |
- Ribeiro, R.M., et al.
(författare)
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Ab initio study of CsI and its surface
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:3, s. 35430-1
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Tidskriftsartikel (refereegranskat)abstract
- Cesium iodide properties, both in the bulk and on (110) and (100) surfaces, are studied using density functional theory. The bulk lattice constant, bulk modulus, and elastic constants are in good agreement with the experimental values. The electronic band structure is also calculated, as well as the density of states. On the surfaces, relaxation of the atoms was performed, and the atomic geometry and electronic structure have been studied
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| 3. |
- Sque, S. J., et al.
(författare)
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Carbon nanotubes and their interaction with the surface of diamond
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:11
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Tidskriftsartikel (refereegranskat)abstract
- Calculations based on density-functional theory have been used to model armchair carbon nanotubes existing in isolation, close-packed into nanoropes, and lying prone on both the hydrogen-terminated and clean (001) surfaces of diamond. In the combined nanotube:diamond systems, the electronic band structures are indicative of electron transfer from the hydrogen-terminated diamond to the physisorbed nanotubes; that is, carbon nanotubes-like C60-appear to be capable of transfer doping diamond p type. Total-energy comparisons with separated systems suggest that the nanotubes are positively bound to the diamond substrate. Diffusion techniques have been used to model movement of the (7,7) nanotube across the hydrogen-terminated diamond surface, with the results suggesting that this substrate presents a rather smooth energy surface to the nanotube; this is consistent with the fact that no covalent bonding across the interface has been found. For comparison, the same nanotube has been modeled above a completely clean diamond (001) surface, and while the nanotube remains bound to the diamond substrate, there is no charge transfer across such an interface.
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| 4. |
- Sque, S.J., et al.
(författare)
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First-principles study of C60 and C60F36 as transfer dopants for p-type diamond
- 2005
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Ingår i: Journal of Physics. - 0953-8984 .- 1361-648X. ; 17:2, s. L21-L26
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio density-functional-theory has been used to investigate transfer doping between C60 monolayers and the hydrogenated (100) diamond surface. An electron transfer from diamond to C60 is predicted for a C60 coverage of around one monolayer, and the possibility of electron transfer is expected to increase for higher coverages, leading to an accumulation of holes at the diamond surface. It has been found that the greater electron affinity of fluorinated C60 is likely to enhance the effect. Results are reported on the structural and electronic properties of isolated C60 and C60F36 molecules, solid C60, and a monolayer of each material adjacent to the (100)-(2 × 1):H diamond surface.
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| 5. |
- Sque, S.J., et al.
(författare)
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Theoretical study on the adsorption of armchair carbon nanotubes on the hydrogenated surface of diamond
- 2006
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Ingår i: Physica Status Solidi (a) applications and materials science. - : Wiley. - 1862-6300 .- 1862-6319. ; 203:12, s. 3107-3113
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Tidskriftsartikel (refereegranskat)abstract
- First-principles density-functional theory has been used to investigate the interaction of (metallic) (7,7) carbon nanotubes with the hydrogenated (001) surface of diamond. There is no evidence for a significant chemical interaction between the nanotubes and the diamond surface, although an appreciable binding energy is obtained. The corresponding electronic band structures are indicative of moderate electron transfer from the diamond substrate to the nanotube, which would in practice leave behind a mobile layer of holes. These results suggest that carbon nanotubes may, like buckminsterfullerene, act as suitable p-type transfer dopants for diamond.
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| 6. |
- Sque, S.J., et al.
(författare)
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Transfer doping of diamond : the use of C60 and C60F36 to effect p-type surface conductivity
- 2006
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 376, s. 268-71
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio density-functional theory is used to determine the suitability for transfer doping of diamond surfaces with various hydrogen and oxygen terminations. Transfer doping of the hydrogenated (0 0 1) diamond surface with C60 is investigated, and electron transfer from diamond to C60 (leaving a hole layer near the diamond surface) is predicted for a C60 coverage of about one monolayer. The efficiency of electron transfer is expected to increase for higher coverages. It is also shown that the greater electron affinity of fluorinated C60 is likely to enhance the effect, in that C60F36 can extract electrons from hydrogenated diamond at much lower coverages. The consequences of oxygenation of the diamond surface on the transfer-doping properties of C60 are also investigated
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| 7. |
- Sque, S.J., et al.
(författare)
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Transfer doping of diamond : Buckminsterfullerene on hydrogenated, hydroxylated, and oxygenated diamond surfaces
- 2006
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Ingår i: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 17:6, s. 459-465
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Tidskriftsartikel (refereegranskat)abstract
- A monolayer of buckminsterfullerene (C60) has been modelled on hydrogenated, hydroxylated (-OH-terminated), and oxygenated diamond surfaces using ab-initio, density-functional-theory calculations, with a view to assessing the likelihood of transfer doping in each case. The C60 layer is predicted to spontaneously extract electrons from the hydrogenated surface, although on the hydroxylated surface there is an energy gap of ~1 eV preventing a similar electron transfer. With the fully oxygenated surface, there is a gap to electron transfer of ~4 eV, effectively prohibiting the transfer-doping effect. In each case, the molecule causes only very little disturbance to the substrate, although chemical reaction remains a significant possibility
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