Open AccessSensitivity of CoWO4 thin films to CO
Author(s) -
Irina Kärkkänen,
Margus Kodu,
Tea Avarmaa,
J. Kozlova,
Leonard Matisen,
Hugo Mändar,
A. Saar,
Väino Sammelselg,
Raivo Jaaniso
Publication year - 2010
Publication title -
procedia engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.32
H-Index - 74
ISSN - 1877-7058
DOI - 10.1016/j.proeng.2010.09.072
Subject(s) - x ray photoelectron spectroscopy , materials science , thin film , annealing (glass) , oxygen , analytical chemistry (journal) , conductivity , relative humidity , stoichiometry , pulsed laser deposition , atmospheric pressure , ambient pressure , electrical resistivity and conductivity , x ray reflectivity , substrate (aquarium) , chemical engineering , composite material , chemistry , nanotechnology , environmental chemistry , engineering , physics , oceanography , electrical engineering , organic chemistry , geology , thermodynamics
A new p-type thin film material for gas sensing was prepared and investigated for CO response. The films of CoWO4 were fabricated by pulsed laser deposition (PLD) and characterised by XRD, XRR, XPS and SEM. The substrate temperature and oxygen pressure in PLD chamber were varied in order to examine the relations between deposition parameters, film structure and gas sensitivity. Conductometric response to CO was measured at 150–350∘C and was found to be the highest at relatively low temperatures, at 200–250∘C depending on relative humidity or annealing time in ambient atmosphere. Highest sensitivity was obtained for the films grown on silicone nitrite substrates at 400–500∘C at oxygen pressures 10−3 to 10−2 mbar. At higher oxygen pressures or after annealing in oxygen environment the film stoichiometry was seriously altered and the conductivity of the films was significantly decreased
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