Structural Properties and Sensing Performance of CeYxOy Sensing Films for Electrolyte–Insulator–Semiconductor pH Sensors
Abstract In this study we developed CeY x O y sensing membranes displaying super-Nernstian pH-sensitivity for use in electrolyte–insulator–semiconductor (EIS) pH sensors. We examined the effect of thermal annealing on the structural properties and sensing characteristics of the CeY x O y sensing mem...
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| Autores principales: | , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Nature Portfolio
2017
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/ff467dd0d7a04bb1bc2570b75cf5e607 |
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| Sumario: | Abstract In this study we developed CeY x O y sensing membranes displaying super-Nernstian pH-sensitivity for use in electrolyte–insulator–semiconductor (EIS) pH sensors. We examined the effect of thermal annealing on the structural properties and sensing characteristics of the CeY x O y sensing membranes deposited through reactive co-sputtering onto Si substrates. X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy revealed the structural, morphological, and chemical features, respectively, of the CeY x O y films after their annealing at 600–900 °C. Among the tested systems, the CeY x O y EIS device prepared with annealing at 800 °C exhibited the highest sensitivity (78.15 mV/pH), the lowest hysteresis voltage (1.4 mV), and the lowest drift rate (0.85 mV/h). Presumably, these annealing conditions optimized the stoichiometry of (CeY)O2 in the film and its surface roughness while suppressing silicate formation at the CeY x O y –Si interface. We attribute the super-Nernstian pH-sensitivity to the incorporation of Y ions in the Ce framework, thereby decreasing the oxidation state Ce (Ce4+ → Ce3+) and resulting in less than one electron transferred per proton in the redox reaction. |
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