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Correlations of charge neutrality level with electronic structure and p-d hybridization

The formation of charge neutrality level (CNL) in highly conducting Cadmium oxide (CdO) thin films is demonstarted by the observed variation in the band gap upon annealing and doping. It may be explained by the observation that Tin (Sn) doping breaks the perfect periodicity of CdO cubic crystal stru...

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Autores principales: Das, Arkaprava, Gautam, Subodh K., Shukla, D. K., Singh, Fouran
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5244377/
https://www.ncbi.nlm.nih.gov/pubmed/28102312
http://dx.doi.org/10.1038/srep40843
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author Das, Arkaprava
Gautam, Subodh K.
Shukla, D. K.
Singh, Fouran
author_facet Das, Arkaprava
Gautam, Subodh K.
Shukla, D. K.
Singh, Fouran
author_sort Das, Arkaprava
collection PubMed
description The formation of charge neutrality level (CNL) in highly conducting Cadmium oxide (CdO) thin films is demonstarted by the observed variation in the band gap upon annealing and doping. It may be explained by the observation that Tin (Sn) doping breaks the perfect periodicity of CdO cubic crystal structure and creates virtual gap states (ViGS). The level of local CNL resides at the branch point of ViGS, making the energy at which native defect’s character changes from predominantly donor-like below CNL to predominantly acceptor-like above the CNL and a schematic band diagram is developed to substantiate the same. Further investigations using soft x-ray absorption spectroscopy (SXAS) at Oxygen and Cadmium edges show the reduction of Sn(4+) to Sn(2+). The analysis of the spectral features has revealed an evidence of p-d interaction between O 2p and Cd 4d orbitals that pushes the valence band minima at higher energies which is symmetry forbidden at г point and causing a positive valance band dispersion away from the zone centre in the г ~ L, K direction. Thus, origin of the CNL is attributed to the high density of the Oxygen vacancies as confirmed by the change in the local electronic structure and p-d hybridization of orbitals.
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spelling pubmed-52443772017-01-23 Correlations of charge neutrality level with electronic structure and p-d hybridization Das, Arkaprava Gautam, Subodh K. Shukla, D. K. Singh, Fouran Sci Rep Article The formation of charge neutrality level (CNL) in highly conducting Cadmium oxide (CdO) thin films is demonstarted by the observed variation in the band gap upon annealing and doping. It may be explained by the observation that Tin (Sn) doping breaks the perfect periodicity of CdO cubic crystal structure and creates virtual gap states (ViGS). The level of local CNL resides at the branch point of ViGS, making the energy at which native defect’s character changes from predominantly donor-like below CNL to predominantly acceptor-like above the CNL and a schematic band diagram is developed to substantiate the same. Further investigations using soft x-ray absorption spectroscopy (SXAS) at Oxygen and Cadmium edges show the reduction of Sn(4+) to Sn(2+). The analysis of the spectral features has revealed an evidence of p-d interaction between O 2p and Cd 4d orbitals that pushes the valence band minima at higher energies which is symmetry forbidden at г point and causing a positive valance band dispersion away from the zone centre in the г ~ L, K direction. Thus, origin of the CNL is attributed to the high density of the Oxygen vacancies as confirmed by the change in the local electronic structure and p-d hybridization of orbitals. Nature Publishing Group 2017-01-19 /pmc/articles/PMC5244377/ /pubmed/28102312 http://dx.doi.org/10.1038/srep40843 Text en Copyright © 2017, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Das, Arkaprava
Gautam, Subodh K.
Shukla, D. K.
Singh, Fouran
Correlations of charge neutrality level with electronic structure and p-d hybridization
title Correlations of charge neutrality level with electronic structure and p-d hybridization
title_full Correlations of charge neutrality level with electronic structure and p-d hybridization
title_fullStr Correlations of charge neutrality level with electronic structure and p-d hybridization
title_full_unstemmed Correlations of charge neutrality level with electronic structure and p-d hybridization
title_short Correlations of charge neutrality level with electronic structure and p-d hybridization
title_sort correlations of charge neutrality level with electronic structure and p-d hybridization
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5244377/
https://www.ncbi.nlm.nih.gov/pubmed/28102312
http://dx.doi.org/10.1038/srep40843
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