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nanomaterials-08-00013-v2.pdf
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Author
Bruzzi, MaraMori, Riccardo
Baldi, Andrea
Carnevale, Ennio
Cavallaro, Alessandro
Scaringella, Monica
Affiliation
Univ Arizona, LBT ObservIssue Date
2018-01-05Keywords
thermally stimulated currentsphotocurrent
titanium dioxide
hopping
nanoporous film
desorption current
chemisorbed current
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Thermally Stimulated Currents in Nanocrystalline Titania 2018, 8 (2):13 NanomaterialsJournal
NanomaterialsRights
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
A thorough study on the distribution of defect-related active energy levels has been performed on nanocrystalline TiO2. Films have been deposited on thick-alumina printed circuit boards equipped with electrical contacts, heater and temperature sensors, to carry out a detailed thermally stimulated currents analysis on a wide temperature range (5-630 K), in view to evidence contributions from shallow to deep energy levels within the gap. Data have been processed by numerically modelling electrical transport. The model considers both free and hopping contribution to conduction, a density of states characterized by an exponential tail of localized states below the conduction band and the convolution of standard Thermally Stimulated Currents (TSC) emissions with gaussian distributions to take into account the variability in energy due to local perturbations in the highly disordered network. Results show that in the low temperature range, up to 200 K, hopping within the exponential band tail represents the main contribution to electrical conduction. Above room temperature, electrical conduction is dominated by free carriers contribution and by emissions from deep energy levels, with a defect density ranging within 10(14)-10(18) cm(-3), associated with physio- and chemi-sorbed water vapour, OH groups and to oxygen vacancies.Note
Open access journal.ISSN
2079-4991Version
Final published versionAdditional Links
http://www.mdpi.com/2079-4991/8/1/13ae974a485f413a2113503eed53cd6c53
10.3390/nano8010013
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Except where otherwise noted, this item's license is described as © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.