Publications
559 results found
Walsh A, Catlow CRA, 2010, Structure, stability and work functions of the low index surfaces of pure indium oxide and Sn-doped indium oxide (ITO) from density functional theory, JOURNAL OF MATERIALS CHEMISTRY, Vol: 20, Pages: 10438-10444, ISSN: 0959-9428
- Author Web Link
- Cite
- Citations: 166
Walsh A, Wei SH, Chen S, et al., 2009, Design of quaternary chalcogenide photovoltaic absorbers through cation mutation, Pages: 001875-001878, ISSN: 0160-8371
Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are identified for two classes of quaternary chalcogenides (I2-II-IV-VI4 and I-III-II2-VI4 systems). For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter η = c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band structure changes on mutation illustrate that although the band gap decreases from binary II-VI to ternary I-III-VI2 are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI 2 to quaternary I2-II-IV-VI4 chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. We find that I2-II-IV- VI4 compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II (001) layer of the kesterite phase. Ten compounds are predicted have band gaps close to the 1 to 2 eV energy window suitable for photovoltaics. ©2009 IEEE.
Yan Y, Walsh A, Da Silva JLF, et al., 2009, Structural, electronic, and optical properties of the In<inf>2</inf>O <inf>3</inf>(ZnO)<inf>n</inf> system, Pages: 000172-000174, ISSN: 0160-8371
We studied the structural, electronic, and optical properties of the In2O3(ZnO)n system by a combination of high-resolution electron microscopy, image simulation, and density-functional theory calculation. We found that the In2O3(ZnO) n system has a polytypoid structure that consists of wurtzite InZnnOn+1 slabs separated by single In-O octahedral layers. These octahedral layers are inversion domain boundaries and satisfy the electronic octet rule. The InZnnOn+1 slabs contain another type of boundary that inverts the polarities again. This boundary prefers a zigzag modulated structure and also obeys the electronic octet rule. We also found that the red-shift in optical transitions for the In2O 3(ZnO)n system as compared to individual In 2O3 and ZnO systems is because the symmetry-forbidden band-edge transitions in In2O3 are overcome by the formation of superlattices, with ZnO contributions to the top of the valence band. We further found that increasing n results in an enhanced valence-band maximum in the ZnO region, while the conduction-band minimum becomes more localized on the InO2 layers, which introduces confinement to electron carriers. Such enhanced localization explains why Zn-rich compounds (higher n) exhibit lower conductivity. ©2009 IEEE.
Da Silva JLF, Walsh A, Wei S-H, et al., 2009, Atomistic origins of the phase transition mechanism in Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub>, JOURNAL OF APPLIED PHYSICS, Vol: 106, ISSN: 0021-8979
- Author Web Link
- Cite
- Citations: 27
Da Silva JLF, Walsh A, Wei S-H, 2009, Theoretical investigation of atomic and electronic structures of Ga<sub>2</sub>O<sub>3</sub>(ZnO)<sub>6</sub>, PHYSICAL REVIEW B, Vol: 80, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 22
Walsh A, Catlow CRA, Sokol AA, et al., 2009, Physical Properties, Intrinsic Defects, and Phase Stability of Indium Sesquioxide, CHEMISTRY OF MATERIALS, Vol: 21, Pages: 4962-4969, ISSN: 0897-4756
- Author Web Link
- Cite
- Citations: 62
Walsh A, Da Silva JLF, Wei S-H, 2009, Interplay between Order and Disorder in the High Performance of Amorphous Transparent Conducting Oxides, Chemistry of Materials, Vol: 21, Pages: 5119-5124, ISSN: 1520-5002
Scanlon DO, Walsh A, Watson GW, 2009, Understanding the p-Type Conduction Properties of the Transparent Conducting Oxide CuBO<sub>2</sub>: A Density Functional Theory Analysis, CHEMISTRY OF MATERIALS, Vol: 21, Pages: 4568-4576, ISSN: 0897-4756
- Author Web Link
- Cite
- Citations: 95
Scanlon DO, Morgan BJ, Watson GW, et al., 2009, Acceptor Levels in p-Type Cu<sub>2</sub>O: Rationalizing Theory and Experiment, PHYSICAL REVIEW LETTERS, Vol: 103, ISSN: 0031-9007
- Author Web Link
- Cite
- Citations: 245
Chen S, Yin W-J, Yang J-H, et al., 2009, Quaternary semiconductors with positive crystal field splitting: Potential high-efficiency spin-polarized electron sources, APPLIED PHYSICS LETTERS, Vol: 95, ISSN: 0003-6951
- Author Web Link
- Cite
- Citations: 13
Koehler RN, Walsh AM, Moqueet N, et al., 2009, High-throughput genotyping of KIR2DL2/L3, KIR3DL1/S1, and their HLA class I ligands using real-time PCR, TISSUE ANTIGENS, Vol: 74, Pages: 73-80, ISSN: 0001-2815
- Author Web Link
- Cite
- Citations: 19
Huda MN, Yan Y, Walsh A, et al., 2009, Group-IIIA versus IIIB delafossites: Electronic structure study, PHYSICAL REVIEW B, Vol: 80, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 74
Huda MN, Yan Y, Walsh A, et al., 2009, Symmetry-breaking-induced enhancement of visible light absorption in delafossite alloys, APPLIED PHYSICS LETTERS, Vol: 94, ISSN: 0003-6951
- Author Web Link
- Cite
- Citations: 20
Yang J-H, Chen S, Yin W-J, et al., 2009, Electronic structure and phase stability of MgTe, ZnTe, CdTe, and their alloys in the B3, B4, and B8 structures, PHYSICAL REVIEW B, Vol: 79, ISSN: 1098-0121
- Author Web Link
- Cite
- Citations: 53
Walsh A, Edwards H, Fraser J, 2009, Attitudes and subjective norms: determinants of parents' intentions to reduce childhood fever with medications, HEALTH EDUCATION RESEARCH, Vol: 24, Pages: 531-545, ISSN: 0268-1153
- Author Web Link
- Cite
- Citations: 17
Li Y-H, Walsh A, Chen S, et al., 2009, Revised ab initio natural band offsets of all group IV, II-VI, and III-V semiconductors, APPLIED PHYSICS LETTERS, Vol: 94, ISSN: 0003-6951
- Author Web Link
- Cite
- Citations: 186
Walsh A, Da Silva JLF, Wei S-H, 2009, Comment on "Theoretical Description of Carrier Mediated Magnetism in Cobalt Doped ZnO'' Reply, PHYSICAL REVIEW LETTERS, Vol: 102, ISSN: 0031-9007
- Author Web Link
- Cite
- Citations: 7
Scanlon DO, Walsh A, Morgan BJ, et al., 2009, Competing defect mechanisms and hydrogen adsorption on Li-doped MgO low index surfaces: A DFT+U study?, Pages: 395-404
Three competing defect configurations of Li-doping of MgO on the (100), (110) and (111) low index surfaces have been investigated using GGA + U. The three configurations investigated on each of the surfaces were: substitution of Li for Mg with the formation of a compensating oxygen hole state ([Li' Mg - O•o]), substitution of Li for Mg with the addition of a Li surface interstitial ([Li'MgLi•i]) and the clustering of two Li ions with the formation of a neutral [Li' MgVo ••Li'Mg] oxygen vacancy. The electronic structure, geometry and energetics of these defects are examined, and the effect on catalytic activity is discussed. Hydrogen abstraction from methane on the three surfaces is also investigated. Our results demonstrate that the energetics associated with hydrogen adsorption are strongly surface dependent, with the (111) oxygen terminated surface indicated as being the most promising catalytically. © 2009 The Surface Science Society of Japan.
Chen S, Gong XG, Walsh A, et al., 2009, Electronic structure and stability of quaternary chalcogenide semiconductors derived from cation cross-substitution of II-VI and I-III-VI<sub>2</sub> compounds, PHYSICAL REVIEW B, Vol: 79, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 464
Kijak GH, Walsh AM, Koehler RN, et al., 2009, HLA class I allele and haplotype diversity in Ugandans supports the presence of a major east African genetic cluster, TISSUE ANTIGENS, Vol: 73, Pages: 262-269, ISSN: 0001-2815
- Author Web Link
- Cite
- Citations: 26
Walsh A, Da Silva JLF, Yan Y, et al., 2009, Origin of electronic and optical trends in ternary In<sub>2</sub>O<sub>3</sub>(ZnO)<sub>n</sub> transparent conducting oxides (n=1,3,5): Hybrid density functional theory calculations, PHYSICAL REVIEW B, Vol: 79, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 68
Arnold T, Payne DJ, Bourlange A, et al., 2009, X-ray spectroscopic study of the electronic structure of CuCrO<sub>2</sub>, PHYSICAL REVIEW B, Vol: 79, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 88
Chen S, Gong XG, Walsh A, et al., 2009, Crystal and electronic band structure of Cu<sub>2</sub>ZnSnX<sub>4</sub> (X=S and Se) photovoltaic absorbers: First-principles insights, APPLIED PHYSICS LETTERS, Vol: 94, ISSN: 0003-6951
- Author Web Link
- Cite
- Citations: 602
Walsh A, Yan Y, Huda MN, et al., 2009, Band Edge Electronic Structure of BiVO4: Elucidating the Role of the Bi s and V d Orbitals, Chemistry of Materials, Vol: 21, Pages: 547-551, ISSN: 1520-5002
We report the first-principles electronic structure of BiVO 4, a promising photocatalyst for hydrogen generation. BiVO 4 is found to be a direct band gap semiconductor, despite having band extrema away from the Brillouin zone center. Coupling between Bi 6s and O 2p forces an upward dispersion of the valence band at the zone boundary; however, a direct gap is maintained via coupling between V 3d, O 2p, and Bi 6p, which lowers the conduction band minimum. These interactions result in symmetric hole and electron masses. Implications for the design of ambipolar metal oxides are discussed. © 2009 American Chemical Society.
Godinho KG, Walsh A, Watson GW, 2009, Energetic and Electronic Structure Analysis of Intrinsic Defects in SnO<sub>2</sub>, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 113, Pages: 439-448, ISSN: 1932-7447
- Author Web Link
- Cite
- Citations: 269
Scanlon DO, Walsh A, Morgan BJ, et al., 2009, Effect of Cr substitution on the electronic structure of CuAl<sub>1-x</sub>Cr<sub>x</sub>O<sub>2</sub>, PHYSICAL REVIEW B, Vol: 79, ISSN: 2469-9950
- Author Web Link
- Cite
- Citations: 114
Yan Y, Walsh A, Da Silva JLF, et al., 2009, STRUCTURAL, ELECTRONIC, AND OPTICAL PROPERTIES OF THE IN<sub>2</sub>O<sub>3</sub>(ZNO)<sub>N</sub> SYSTEM, 34th IEEE Photovoltaic Specialists Conference, Publisher: IEEE, Pages: 2234-2236, ISSN: 0160-8371
Walsh A, Ahn K-S, Shet S, et al., 2009, Ternary cobalt spinel oxides for solar driven hydrogen production: Theory and experiment, ENERGY & ENVIRONMENTAL SCIENCE, Vol: 2, Pages: 774-782, ISSN: 1754-5692
- Author Web Link
- Cite
- Citations: 56
Walsh AM, Perret K, Koehler R, et al., 2009, Genetic complexity of TRIM5 and APOBEC in East Africa, Publisher: BIOMED CENTRAL LTD, ISSN: 1742-4690
Koehler RN, Walsh AM, Saathoff E, et al., 2009, HLA-A*7401 is associated with protection from HIV-1 acquisition and disease progression in Mbeya, Tanzania, Publisher: BIOMED CENTRAL LTD, ISSN: 1742-4690
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.