ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humid... more ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humidity sensing elements, obtained by the deposition of Ti-Si-oxide films in the presence of a Ce-dopant via a sol-gel method using titanium (IV) n-butoxide and polydimethylsiloxane as basic precursors. The proportion between these precursors predetermines the mechanism of polymerization and subsequent gel-formation. As a result, this affects the structure and porosity of the obtained films after their sintering and also their response to humidity. The electrical characteristics of the respective samples were examined by an impedance analyzer. The sintered oxide films were observed by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis. The sensing elements obtained are distinguished for their high response to humidity and the variation in their resistance reaches up to four orders within the range of 15-93% relative humidity at 20 Hz and 25 °C.
Humidity sensing elements were elaborated by deposition of Ce-doped SiO2 films on alumina ceramic... more Humidity sensing elements were elaborated by deposition of Ce-doped SiO2 films on alumina ceramic substrates with silver-palladium electrodes, via sol-gel method. The obtained specimens were sintered either at 400°C, or at 800°C, in order to create durable and reliable sensors and to evaluate the impact of the thermal treatment on the features of the obtained sensing elements. The superficial morphology, and composition of the films, and the electrical characteristics of the respective sensors were investigated. The impedance spectra of the sensing elements were fitted to appropriate equivalent electric circuit. The results obtained show that both of the addition Се(NO3)3 and the sintering at 400°С lead to remarkable improvement of the sensitivity of the SiO2-based sensing elements.
Abstract The present work deals with the comparative investigations of the combined influence of ... more Abstract The present work deals with the comparative investigations of the combined influence of precursors of TiO 2 and SiO 2 : Tetrabutyl orthotitanate, Tetraethoxysilane and (3-Glycidyloxypropyl)trimethoxysilane in the presence of Ce-ions on the properties of the respective thin film humidity sensing elements prepared via a sol–gel method and sintered at 400 °C. SEM, EDX and XRD analyses of the obtained samples have been carried out to study their surface morphology and structural composition. The electrical characteristics and parameters of the samples have been investigated by means of an impedance analyzer. It has been established that the type and proportions of the precursors substantially affect the structure of the films obtained and their humidity sensing properties. The combination of both types of precursors of TiO 2 and SiO 2 in all cases results in an enhancement of the sensor elements’ response to humidity compared to the use of only one of these precursors. The change in resistance of the samples reaches about four orders of magnitude within the range from 15 to 93% relative humidity at a frequency of 20 Hz and at 25 °C.
The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed usi... more The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed using a sol-gel technology and a thermal treatment at 400°C or 800°C. Titanium (IV) n-butoxide and polydimethylsiloxane have been used as titania and silica precursors. Cerium is included in the resulting system via a saturated liquid solution of diammonium hexanitrocerate in isobutanol. It provides sufficiently acidic environment for the running of the hydrolysis processes in the sol-gel system. Zinc nitrate hexahydrate and copper (II) nitrate trihydrate have been used as dopant sources of Zn and Cu. The electrical characteristics, topological features and chemical compositions of the obtained layers have been studied. The frequency characteristics of the samples have been investigated for frequencies from 20 Hz to 1 MHz. The sensitivity of the proposed sensors regarding the environment humidity is significant. The resistance variation of the sensors, sintered at 800°C, amounts to five ord...
This paper presents humidity sensing elements based on Si-Bi-O surface layers prepared via a sol-... more This paper presents humidity sensing elements based on Si-Bi-O surface layers prepared via a sol-gel method and sintered at 400 °C and 800 °C. Tetraethoxysilane has been used as silica precursor and Bismuth acetate as dopant source. Morphological and map-data analysis of these layers has been carried out by means of scanning electron microscopy and dispersive spectroscopy. X-ray diffraction analysis has been carried out to study the structural composition of the material of the sensing layers. The electrical properties of the sensing elements have been studied with a precise impedance analyzer. The influence of frequency within the range of 20 Hz to 1 MHz on the characteristics of samples has also been studied. The developed sensing elements have very high sensitivity to humidity, small hysteresis, and short response and recovery time. The change in the resistance of the samples, sintered at 400 °C, reaches about six orders of magnitude within the range from 17% to 93% relative humidity at a frequency of 20 Hz and at 25 °C.
The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed usi... more The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed using a sol-gel technology and a thermal treatment at 400°C or 800°C. Titanium (IV) n-butoxide and polydimethylsiloxane have been used as titania and silica precursors. Cerium is included in the resulting system via a saturated liquid solution of diammonium hexanitrocerate in isobutanol. It provides sufficiently acidic environment for the running of the hydrolysis processes in the sol-gel system. Zinc nitrate hexahydrate and copper (II) nitrate trihydrate have been used as dopant sources of Zn and Cu. The electrical characteristics, topological features and chemical compositions of the obtained layers have been studied. The frequency characteristics of the samples have been investigated for frequencies from 20 Hz to 1 MHz. The sensitivity of the proposed sensors regarding the environment humidity is significant. The resistance variation of the sensors, sintered at 800°C, amounts to five ord...
The monitoring and control of the ambient medium parameters demand appropriate and reliable senso... more The monitoring and control of the ambient medium parameters demand appropriate and reliable sensors. The present work presents the development of humidity sensing elements based on Cedoped Ti-Si-Zr-O surface layers. Since the sensor performance is entirely predetermined by the compositional, morphological and structural features of the composing materials, their dependence of the sintering temperature was evaluated by Scanning Electron Microscopy (SEM), and X-Ray Diffractometry (XRD) for morphological structural characterization. The dependency of these results and the impedance characteristics for the respective sensing elements was analyzed.
ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humid... more ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humidity sensing elements, obtained by the deposition of Ti-Si-oxide films in the presence of a Ce-dopant via a sol-gel method using titanium (IV) n-butoxide and polydimethylsiloxane as basic precursors. The proportion between these precursors predetermines the mechanism of polymerization and subsequent gel-formation. As a result, this affects the structure and porosity of the obtained films after their sintering and also their response to humidity. The electrical characteristics of the respective samples were examined by an impedance analyzer. The sintered oxide films were observed by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis. The sensing elements obtained are distinguished for their high response to humidity and the variation in their resistance reaches up to four orders within the range of 15-93% relative humidity at 20 Hz and 25 °C.
ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humid... more ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humidity sensing elements, obtained by the deposition of Ti-Si-oxide films in the presence of a Ce-dopant via a sol-gel method using titanium (IV) n-butoxide and polydimethylsiloxane as basic precursors. The proportion between these precursors predetermines the mechanism of polymerization and subsequent gel-formation. As a result, this affects the structure and porosity of the obtained films after their sintering and also their response to humidity. The electrical characteristics of the respective samples were examined by an impedance analyzer. The sintered oxide films were observed by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis. The sensing elements obtained are distinguished for their high response to humidity and the variation in their resistance reaches up to four orders within the range of 15-93% relative humidity at 20 Hz and 25 °C.
Humidity sensing elements were elaborated by deposition of Ce-doped SiO2 films on alumina ceramic... more Humidity sensing elements were elaborated by deposition of Ce-doped SiO2 films on alumina ceramic substrates with silver-palladium electrodes, via sol-gel method. The obtained specimens were sintered either at 400°C, or at 800°C, in order to create durable and reliable sensors and to evaluate the impact of the thermal treatment on the features of the obtained sensing elements. The superficial morphology, and composition of the films, and the electrical characteristics of the respective sensors were investigated. The impedance spectra of the sensing elements were fitted to appropriate equivalent electric circuit. The results obtained show that both of the addition Се(NO3)3 and the sintering at 400°С lead to remarkable improvement of the sensitivity of the SiO2-based sensing elements.
Abstract The present work deals with the comparative investigations of the combined influence of ... more Abstract The present work deals with the comparative investigations of the combined influence of precursors of TiO 2 and SiO 2 : Tetrabutyl orthotitanate, Tetraethoxysilane and (3-Glycidyloxypropyl)trimethoxysilane in the presence of Ce-ions on the properties of the respective thin film humidity sensing elements prepared via a sol–gel method and sintered at 400 °C. SEM, EDX and XRD analyses of the obtained samples have been carried out to study their surface morphology and structural composition. The electrical characteristics and parameters of the samples have been investigated by means of an impedance analyzer. It has been established that the type and proportions of the precursors substantially affect the structure of the films obtained and their humidity sensing properties. The combination of both types of precursors of TiO 2 and SiO 2 in all cases results in an enhancement of the sensor elements’ response to humidity compared to the use of only one of these precursors. The change in resistance of the samples reaches about four orders of magnitude within the range from 15 to 93% relative humidity at a frequency of 20 Hz and at 25 °C.
The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed usi... more The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed using a sol-gel technology and a thermal treatment at 400°C or 800°C. Titanium (IV) n-butoxide and polydimethylsiloxane have been used as titania and silica precursors. Cerium is included in the resulting system via a saturated liquid solution of diammonium hexanitrocerate in isobutanol. It provides sufficiently acidic environment for the running of the hydrolysis processes in the sol-gel system. Zinc nitrate hexahydrate and copper (II) nitrate trihydrate have been used as dopant sources of Zn and Cu. The electrical characteristics, topological features and chemical compositions of the obtained layers have been studied. The frequency characteristics of the samples have been investigated for frequencies from 20 Hz to 1 MHz. The sensitivity of the proposed sensors regarding the environment humidity is significant. The resistance variation of the sensors, sintered at 800°C, amounts to five ord...
This paper presents humidity sensing elements based on Si-Bi-O surface layers prepared via a sol-... more This paper presents humidity sensing elements based on Si-Bi-O surface layers prepared via a sol-gel method and sintered at 400 °C and 800 °C. Tetraethoxysilane has been used as silica precursor and Bismuth acetate as dopant source. Morphological and map-data analysis of these layers has been carried out by means of scanning electron microscopy and dispersive spectroscopy. X-ray diffraction analysis has been carried out to study the structural composition of the material of the sensing layers. The electrical properties of the sensing elements have been studied with a precise impedance analyzer. The influence of frequency within the range of 20 Hz to 1 MHz on the characteristics of samples has also been studied. The developed sensing elements have very high sensitivity to humidity, small hysteresis, and short response and recovery time. The change in the resistance of the samples, sintered at 400 °C, reaches about six orders of magnitude within the range from 17% to 93% relative humidity at a frequency of 20 Hz and at 25 °C.
The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed usi... more The paper proposes humidity sensors on the base of Ti-Si-Ce-Zn-Cu-O surface layers, developed using a sol-gel technology and a thermal treatment at 400°C or 800°C. Titanium (IV) n-butoxide and polydimethylsiloxane have been used as titania and silica precursors. Cerium is included in the resulting system via a saturated liquid solution of diammonium hexanitrocerate in isobutanol. It provides sufficiently acidic environment for the running of the hydrolysis processes in the sol-gel system. Zinc nitrate hexahydrate and copper (II) nitrate trihydrate have been used as dopant sources of Zn and Cu. The electrical characteristics, topological features and chemical compositions of the obtained layers have been studied. The frequency characteristics of the samples have been investigated for frequencies from 20 Hz to 1 MHz. The sensitivity of the proposed sensors regarding the environment humidity is significant. The resistance variation of the sensors, sintered at 800°C, amounts to five ord...
The monitoring and control of the ambient medium parameters demand appropriate and reliable senso... more The monitoring and control of the ambient medium parameters demand appropriate and reliable sensors. The present work presents the development of humidity sensing elements based on Cedoped Ti-Si-Zr-O surface layers. Since the sensor performance is entirely predetermined by the compositional, morphological and structural features of the composing materials, their dependence of the sintering temperature was evaluated by Scanning Electron Microscopy (SEM), and X-Ray Diffractometry (XRD) for morphological structural characterization. The dependency of these results and the impedance characteristics for the respective sensing elements was analyzed.
ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humid... more ABSTRACT This paper presents the studies of the characteristics and parameters of thin film humidity sensing elements, obtained by the deposition of Ti-Si-oxide films in the presence of a Ce-dopant via a sol-gel method using titanium (IV) n-butoxide and polydimethylsiloxane as basic precursors. The proportion between these precursors predetermines the mechanism of polymerization and subsequent gel-formation. As a result, this affects the structure and porosity of the obtained films after their sintering and also their response to humidity. The electrical characteristics of the respective samples were examined by an impedance analyzer. The sintered oxide films were observed by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis. The sensing elements obtained are distinguished for their high response to humidity and the variation in their resistance reaches up to four orders within the range of 15-93% relative humidity at 20 Hz and 25 °C.
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