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Publikācija: Influence of Iron Non-Stoichiometry on Spinel Zinc Ferrite Gas Sensing Properties

Publication Type Scientific article indexed in SCOPUS or WOS database
Funding for basic activity Unknown
Defending: ,
Publication language English (en)
Title in original language Influence of Iron Non-Stoichiometry on Spinel Zinc Ferrite Gas Sensing Properties
Field of research 2. Engineering and technology
Sub-field of research 2.5 Materials engineering
Authors Andris Šutka
Gundars Mežinskis
Andrejs Lūsis
Dmitrijs Jakovļevs
Keywords Zinc ferrite, gas sensor, non-stoichiometry, nanomaterial, impedance spectroscopy
Abstract It is demonstrated for the first time that the gas sensing properties of a spinel ferrite complex metal oxide semiconductor can be improved by controlling iron stoichiometry. Conductivity and sensitivity was analysed for ZnFe2+zO4± spinel type ferrite with z from -0,01 to 0,15. By increasing iron content from z=-0,01 to z=0,1, sensitivity increases up to 3 times but for samples with z>0,1 sensitivity drops. It was observed from impedance spectroscopy measurements that resistance decreases with an increase of the iron content. Complex impedance spectra reveal two phases with different resistance attributed to depletion layer (Rd) and bulk (Rb). With increasing iron content increases Rd/Rb ratio due to decrease of depletion layer width. Outer surface of the grain of the sensing material estimated higher ratio (Rd(air)/Rd(gas)) with gas exposure in comparison with bulk (Rb(air)/Rb(gas)). Overall sensitivity increases due to increase of donor concentration leading down to increase adsorbed oxygen species on grain surface. Sensitivity drops when z > 0,1 due to remarkable decrease of depletion layer width.
DOI: 10.1016/j.snb.2012.03.012
Reference Šutka, A., Mežinskis, G., Lūsis, A., Jakovļevs, D. Influence of Iron Non-Stoichiometry on Spinel Zinc Ferrite Gas Sensing Properties. Sensors and Actuators B: Chemical, 2012, Vol.171-172, pp.204-209. ISSN 0925-4005. Available from: doi:10.1016/j.snb.2012.03.012
Additional information Citation count:
ID 13036