| 1. |
- Coomer, B.J., et al.
(författare)
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Identification of the tetra-interstitial in silicon
- 2001
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 13:1, s. L1-L7
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Tidskriftsartikel (refereegranskat)abstract
- First-principles computational methods are employed to investigate the structural, vibrational, optical and electronic properties of the self-interstitial aggregate, I4 in silicon. We find the defect to be electrically active and identify it with the B3 EPR centre. We also show that its properties are consistent with DLTS and optical spectra observed following implantation of silicon.
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| 2. |
- Coomer, B.J., et al.
(författare)
-
Interstitial aggregates and a new model for the I1/W optical centre in silicon
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 273-274, s. 505-508
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Tidskriftsartikel (refereegranskat)abstract
- The properties of di-interstitial (I2), tri-interstitial (I3) and tetra-interstitial (I4) structures in silicon were studied by employing first principles local-density-functional (LDF) theory. A tri-interstitial defect can account for many of the fundamental properties of the I1/W-optical center which is observed in irradiated, annealed silicon. Energy comparisons between di-interstitial defects reveal four low-energy structures within 0.5 eV of each other.
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| 3. |
- Coomer, B.J., et al.
(författare)
-
The divacancy in silicon and diamond
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 273-274, s. 520-523
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Tidskriftsartikel (refereegranskat)abstract
- First-principles studies of the divacancy (V2) in both silicon and diamond are reported. We demonstrate that the contrasting experimental spin-density localisation of both systems can be explained through the one-electron pictures arising from opposing distortions
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| 4. |
- Coomer, B.J., et al.
(författare)
-
Vacancy-hydrogen complexes in germanium
- 1998
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Ingår i: E-MRS Meeting. - : European Materials Research Society.
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Konferensbidrag (refereegranskat)abstract
- Local-density-functional pseudopotential theory is used to investigate the structural, electronic and vibrational properties of vacancy-hydrogen complexes in germanium. The results are compared with recent infrared absorption data from proton and deuteron implanted Ge. The acceptor and donor levels of the VH defects are derived semi-empirically from the relaxed structures
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| 5. |
- Coomer, B.J., et al.
(författare)
-
Vacancy-hydrogen complexes in germanium
- 1999
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 58:1-2, s. 36-38
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Tidskriftsartikel (refereegranskat)abstract
- Local-density-functional pseudopotential theory is used to investigate the structural, electronic and vibrational properties of vacancy-hydrogen complexes in germanium. The results are compared with recent infrared absorption data from proton and deuteron implanted Ge. The acceptor and donor levels of the VHn defects are derived semi-empirically from the relaxed structures
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| 6. |
- Eberlein, T.A.G., et al.
(författare)
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Self-interstitial clusters in silicon
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308-310, s. 454-457
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Tidskriftsartikel (refereegranskat)abstract
- Although there have been made many calculations for structures of the self-interstitial in Si and small aggregates of interstitials, In, there have been relatively few attempts to relate these defects with experimental data. Here, we discuss the assignments of the self-interstitial to the AA12 EPR centre and the di-interstitial to the P6 EPR centre.
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| 7. |
- Goss, J.P., et al.
(författare)
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Extended defects in diamond: the interstitial platelet
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 67:16, s. 165208-1
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Tidskriftsartikel (refereegranskat)abstract
- The structure and properties of the {001} planar platelet in diamond are investigated using ab initio theory. We find that a carbonaceous model, based on a layer of self-interstitials, satisfies the requirements of transmission electron microscopy, infrared absorption data, and energetic considerations. The energetics of self-interstitial production during nitrogen aggregation are considered. It is found that the growth mechanism of the platelet involves a thermally activated release of vacancies from platelets. The role of vacant sites and platelet nitrogen are also investigated and it is shown that these defects embedded within the platelet could account for the observed optical activity.
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| 8. |
- Goss, J.P., et al.
(författare)
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Interstitial aggregates in diamond
- 2001
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Ingår i: Diamond and related materials. - 0925-9635 .- 1879-0062. ; 10:3, s. 434-438
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical modelling of magnetic resonance signals lead to convincing models for the first three self-interstitial aggregates in diamond. These in turn suggest the manner in which larger more stable aggregates including the platelet, observed in annealed type I diamonds, are formed.
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| 9. |
- Goss, J.P., et al.
(författare)
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Self-interstitial aggregation in diamond
- 2001
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 63:19, s. 195208-
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Tidskriftsartikel (refereegranskat)abstract
- First-principles methods are used to investigate the self-interstitial and its aggregates in diamond. The experimental assignment of the spin-1 R2 EPR center to the single interstitial has been questioned because of the small fine-structure term observed. We calculate the spin-spin interaction tensor for the three interstitial defects I1〈001〉, I2NN, and I3 and compare with the experimental D tensors. The results give support for the assignments of the single and di-interstitials to microscopic models and allow us to conclusively identify a recently observed EPR center, O3, with I3. This identification, in turn, suggests a low-energy structure for I4 and a generic model for an extended defect called the platelet. We also determine the optical properties of I1〈001〉 as well as its piezospectroscopic or stress tensor and find these to be in agreement with experiment. Several multi-interstitial defects are found to possess different structural forms which may coexist. We propose that a different form of the charged I2 defect gives rise to the 3H optical peak. Several structures of the platelet are considered, and we find that the lowest-energy model is consistent with microscopic and infrared studies.
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| 10. |
- Goss, J.P., et al.
(författare)
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Small aggregates of interstitials and models for platelets in diamond
- 2000
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 12:49, s. 10257-10261
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Tidskriftsartikel (refereegranskat)abstract
- By examining the structure of small clusters of self-interstitials in diamond using local-density-functional techniques, we have developed models for the planar defects called platelets. We present the structures, energies and vibrational properties
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