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Electronic and opti...
Electronic and optical properties of nanocrystalline WO3 thin films studied by optical spectroscopy and density functional calculations
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- Johansson, Malin B. (författare)
- Uppsala universitet,Fasta tillståndets fysik,Uppsala University, Sweden
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- Baldissera, Gustavo (författare)
- KTH,Tillämpad materialfysik,Kungliga Tekniska Högskolan,Royal Institute of Technology KTH, Stockholm, Sweden
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- Valyukh, Iryna (författare)
- Linköpings universitet,Tillämpad optik,Tekniska högskolan
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- Persson, Clas (författare)
- KTH,Tillämpad materialfysik,University of Oslo, Norway,Kungliga Tekniska Högskolan,Royal Institute of Technology KTH, Stockholm, Sweden
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- Arwin, Hans (författare)
- Linköpings universitet,Tillämpad optik,Tekniska högskolan
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- Niklasson, Gunnar A., 1953- (författare)
- Uppsala universitet,Fasta tillståndets fysik,Uppsala University, Sweden
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- Österlund, Lars (författare)
- Uppsala universitet,Fasta tillståndets fysik,Uppsala University, Sweden
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(creator_code:org_t)
- 2013-04-25
- 2013
- Engelska.
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 25:20, s. 205502-
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- The optical and electronic properties of nanocrystalline WO3 thin films prepared by reactive dc magnetron sputtering at different total pressures (P-tot) were studied by optical spectroscopy and density functional theory (DFT) calculations. Monoclinic films prepared at low P-tot show absorption in the near infrared due to polarons, which is attributed to a strained film structure. Analysis of the optical data yields band-gap energies E-g approximate to 3.1 eV, which increase with increasing P-tot by 0.1 eV, and correlate with the structural modifications of the films. The electronic structures of triclinic delta-WO3, and monoclinic gamma- and epsilon-WO3 were calculated using the Green function with screened Coulomb interaction (GW approach), and the local density approximation. The delta-WO3 and gamma-WO3 phases are found to have very similar electronic properties, with weak dispersion of the valence and conduction bands, consistent with a direct band-gap. Analysis of the joint density of states shows that the optical absorption around the band edge is composed of contributions from forbidden transitions (>3 eV) and allowed transitions (>3.8 eV). The calculations show that E-g in epsilon-WO3 is higher than in the delta-WO3 and gamma-WO3 phases, which provides an explanation for the P-tot dependence of the optical data.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- Microscopic Surface-Roughness
- Augmented-Wave Method
- Tungsten-Oxide
- Phase-Transitions
- Crystal-Structure
- Smart Windows
- Trioxide
- Electrochromics
- Photoemission
- Dependence
- Engineering Science with specialization in Solid State Physics
- TECHNOLOGY
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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