Local Structure and Surface Properties of CoxZn1-xO Thin Films for Ozone Gas Sensing.
A detailed study of the structural, surface, and gas-sensing properties of nanostructured CoxZn1-xO films is presented. X-ray diffraction (XRD) analysis revealed a decrease in the crystallization degree with increasing Co content. The X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopies (XPS) revealed that the Co2+ions preferentially occupied the Zn2+sites and that the oxygen vacancy concentration increased as the amount of cobalt increased. Electrical measurements showed that the Co dopants not only enhanced the sensor response at low ozone levels (ca. 42 ppb) but also led to a decrease in the operating temperature and improved selectivity. The enhancement in the gas-sensing properties was attributed to the presence of oxygen vacancies, which facilitated ozone adsorption.
Institute of Physics of São Carlos, University of São Paulo , Av. Trabalhador Sãocarlense 400, 13566-590, São Carlos, SP Brazil.
Ariadne C
AC
Catto
Institute of Chemistry, São Paulo State University , P.O. Box 355, 14800-900 Araraquara, SP Brazil.
Luís F da
LF
Silva
Institute of Physics of São Carlos, University of São Paulo , Av. Trabalhador Sãocarlense 400, 13566-590, São Carlos, SP Brazil.
Maria Inês B
MI
Bernardi
Aix-Marseille University, CNRS , IM2NP 7334, Av. E. N. Neimen, 13397 Marseille, France.
Sandrine
S
Bernardini
Aix-Marseille University, CNRS , IM2NP 7334, Av. E. N. Neimen, 13397 Marseille, France.
Khalifa
K
Aguir
Institute of Chemistry, São Paulo State University , P.O. Box 355, 14800-900 Araraquara, SP Brazil.
Elson
E
Longo
Institute of Physics of São Carlos, University of São Paulo , Av. Trabalhador Sãocarlense 400, 13566-590, São Carlos, SP Brazil.
Valmor R
VR
Mastelaro
XANES spectroscopy; XPS; cobalt; gas sensor; ozone; zinc oxide