Hybrid functional studies of the oxygen vacancy in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>TiO</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

Janotti, Anderson; Varley, Joel B.; Rinke, Patrick; Umezawa, Naoto; Kresse, Georg; Walle, Chris G. Van de

doi:10.1103/physrevb.81.085212

Cited by 576 publications

(450 citation statements)

References 39 publications

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“…Recently, DFT methods beyond conventional DFT, specifically the LDA+U method 14 as well as hybrid functionals 15 , have been used to study TiO 2 , yielding in general satisfactory results. 7,16,17 For example, the experimental band gap of pristine TiO 2 is reproduced, and the relative stability of various vacancy charge states and the location of defect states in the band gap also agree well with experiments.…”

Section: Introductionsupporting

confidence: 64%

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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Understanding electronic properties of sub-stoichiometric phases of titanium oxide such as Magnéli phase Ti 4 O 7 is crucial in designing and modeling resistive switching devices. Here we present our study on Magnéli phase Ti 4 O 7 together with rutile TiO 2 and Ti 2 O 3 using density functional theory methods with atomic-orbital-based self-interaction correction (ASIC). We predict a new antiferromagnetic ground state in the low temperature phase (or LT phase), and we explain energy difference with a competing antiferromagnetic state using a Heisenberg model. The predicted energy ordering of these states in the LT phase is calculated to be robust in a wide range of modeled isotropic strain. We have also investigated the dependence of the electronic structures of the Ti-O phases on stoichiometry. The splitting of titanium t 2g orbitals is enhanced with increasing oxygen deficiency as Ti-O is reduced. The electronic properties of all these phases can be reasonably well described by applying ASIC with a 'standard' value for transition metal oxides of the empirical parameter α of 0.5 representing the magnitude of the applied self-interaction correction.

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Section: Introductionsupporting

confidence: 64%

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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“…43 However, in the literature lattice contraction is evidenced under the inuence of V O s. 45 In the case of TiO 2 when an O atom is removed, the three nearest Ti atoms tend to relax away from the vacancy in the process of strengthening their bonding with the rest of the lattice. 45,46 In the present case, most probably because of the low density of V O s, a negligible effect on the bond lengths/cell volume is seen. Moving onto the XRD pattern of the TiO 2 -ZnO CSHJ sample, we have identied reections of the hexagonal (wurtzite) ZnO and annotated the corresponding Miller indices on Fig.…”

Section: Photocatalytic Activity Of Core-shell Heterojunction Nanobersmentioning

confidence: 46%

Selective isolation of the electron or hole in photocatalysis: ZnO–TiO2 and TiO2–ZnO core–shell structured heterojunction nanofibers via electrospinning and atomic layer deposition

et al. 2014

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Heterojunctions are a well-studied material combination in photocatalysis studies, the majority of which aim to improve the efficacy of the catalysts. Developing novel catalysts begs the question of which photo-generated charge carrier is more efficient in the process of catalysis and the associated mechanism. To address this issue we have fabricated core-shell heterojunction (CSHJ) nanofibers from ZnO and TiO 2 in two combinations where only the 'shell' part of the heterojunction is exposed to the environment to participate in the photocatalysis. Core and shell structures were fabricated via electrospinning and atomic layer deposition, respectively which were then subjected to calcination. These CSHJs were characterized and studied for photocatalytic activity (PCA). These two combinations expose electrons or holes selectively to the environment. Under suitable illumination of the ZnO-TiO 2 CSHJ, e/h pairs are created mainly in TiO 2 and the electrons take part in catalysis (i.e. reduce the organic dye) at the conduction band or oxygen vacancy sites of the 'shell', while holes migrate to the core of the structure. Conversely, holes take part in catalysis and electrons diffuse to the core in the case of a TiO 2 -ZnO CSHJ. The results further revealed that the TiO 2 -ZnO CSHJ shows $1.6 times faster PCA when compared to the ZnO-TiO 2 CSHJ because of efficient hole capture by oxygen vacancies, and the lower mobility of holes.

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“…Since defect levels are sensitive not to the band gap itself, but to their position relative to the host band states, this ambiguity can result in many different predictions for defect ground states. 5,6,25 Furthermore, corrections for SIE are especially important for charged defect calculations as reducing interaction error tends to increase the ionicity of the crystal 26 resulting in more ionic relaxation as a defect state is populated and hence greater energy benefit for a charged defect.…”

Section: Band-gap Errormentioning

confidence: 99%

Intrinsic defects and dopability of zinc phosphide

Demers

Walle

2012

Phys. Rev. B

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Zinc phosphide (Zn 3 P 2 ) could be the basis for cheap and highly efficient solar cells. Its use in this regard is limited by the difficulty in n-type doping of the material. In an effort to understand the mechanism behind this, the energetics and electronic structure of intrinsic point defects in zinc phosphide are studied using generalized Kohn-Sham theory and utilizing the Heyd, Scuseria, and Ernzerhof (HSE) hybrid functional for exchange and correlation. Novel "perturbation extrapolation" is utilized to extend the use of the computationally expensive HSE functional to this large-scale defect system. According to calculations, the formation energy of charged phosphorus interstitial defects are very low in n-type Zn 3 P 2 and act as "electron sinks," nullifying the desired doping and lowering the Fermi-level back toward the p-type regime. This is consistent with experimental observations of both the tendency of conductivity to rise with phosphorus partial pressure, and with current partial successes in n-type doping in very zinc-rich growth conditions.

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Hybrid functional studies of the oxygen vacancy inTiO2

Cited by 576 publications

References 39 publications

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Selective isolation of the electron or hole in photocatalysis: ZnO–TiO2 and TiO2–ZnO core–shell structured heterojunction nanofibers via electrospinning and atomic layer deposition

Intrinsic defects and dopability of zinc phosphide

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