Download or read book Fabrication of Thin Film Tin Oxide Gas Sensors by Sol gel Technique written by Arporn Teeramongkonrasmee and published by . This book was released on 1998 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, a systematic study involving the fabrication of thin film SnO2 gas sensors by sol-gel technique had been carried out. The sol solution of SnO2 was prepared by chemical synthesis process. Tin tetrachloride and sodium ethoxide were used as the fundamental reactants. The synthesis sol had been coated on the glass substrate by spin coating technique to form thin films. The coated films were then subjected to anneal at 550 C for 1 hour to change their structure to SnO2. It was found that the thickness of SnO2 films could be linearly controlled by varying the number of coatings. The thickness of each coating was about 350 A. In order to analyze the gas sensing performance quantitatively, a novel gas measuring circuit was proposed. This circuit could be used to calculate sensitivity and recovery time without depending on the external circuit components such as resistance. The performance of this proposed circuit had been compared with that of the conventional circuit in both theoretical and experiment aspects. The results indicated the conventional measuring circuit is not suitable for calculating gas sensitivity in the case which a semiconductor gas sensor under test has a nonlinear I-V characteristic. For the proposed sircuit, this nonlinear property did not cause any problem in calculating sensitivity. Moreover, the gas sensing performance of various gas sensors could be compared quantitatively if the bias voltage of all gas sensors were set to the same value. The characterization of the fabricating gas sensors had been performed on a flow injection system combining with the proposed measuring circuit. The sensitivity of gas sensor had been found to be strongly dependent on the film thickness. The experiments showed that the optimum thickness was about 1000 A. From the gas response tests to alcohol and ammonia solutions, it was found that the unmodified SnO2 gas sensor gave the highest sensitivity. The addition of some modified substances such as CuSO4, AgNO3 and Au reduced the gas sensitivity. However, there was a tendency to increase sensitivity by adding FeCl3. By using the power law model to analyze the change of sensitivity with sample concentration, it was found that the unmodified SnO2 gas sensor could be used to detect alcohol and ammonia in the range of 0.08-10 and 0.05-10% by volume respectively. The optimum operating temperature was 250 C for alcohol detection and 350 C ammonia detection.

Download or read book Tests and Fabrication of Thin Films of Tin Oxide to be Used as Gas Sensors written by Lavi B. Malhotra and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Characterization of Mixed Transition Metal Oxide Thin Film Gas Sensors Derived Trhough Sol gel Chemistry written by Lee Wesley Hoffman and published by . This book was released on 1996 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication of Gas Sensors Based on Aluminum Tin Oxide ATO Thin Films Decorated with Catalytic Metal Nano Particles written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensors for Environment Health and Security written by M.-I. Baraton and published by Springer Science & Business Media. This book was released on 2008-11-25 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NATO Advanced Study Institute on “Sensors for Environment, Health and Security: Advanced Materials and Technology” was held in Vichy (France) on September 16–27, 2007 where more than 65 participants, ranging from Ph. D. students to experienced senior scientists, met and exchanged ideas and know-how in a friendly atmosphere. The present book intends to cover the main topics of this NATO ASI through 32 chapters distributed over two parts (Part I: “Materials and Technologies” and Part II: “Applications to Environment, Health and Security”). The scientific programme of the NATO ASI consisted in 28 1-hour lectures given by 14 invited lecturers, 5 additional 1-hour lectures given by seminar speakers, 22 oral presentations by selected ASI participants and a poster session. The programme was divided into four sessions: (1) Advanced materials and technologies; (2) Sensors for environment; (3) Sensors for health; (4) Sensors for security. During the “Advanced Materials and Technologies” session (Part I of the present book), the lectures were dedicated to critical analyses of current methods for the synthesis of materials, nanomaterials (nanoparticles, nanowires, nanotubes, ...) and nanocomposites to be used for the fabrication of sensing devices, mainly semiconductor sensors. Among the synthesis methods, chemical (sol-gel, etc. ) and physical methods (laser deposition, DC magnetron sputtering, etc. ) were discussed. Several lectures addressed characterization techniques and it was concluded that the physical and chemical control of the materials/nanomaterials, including surface chemistry, remains a key issue for the reproducibility of the final device.

Download or read book Fabrication of Gas Sensors Based on Gallium Tin Oxide GTO Thin Films Decorated with Catalytic Metal Nano Particles written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sol Gel Derived Titania Films And Their Potential Application As Gas Sensor written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Today there is a great deal of interest in the development of gas sensors for various applications like monitoring of toxic gases, detection in oil reservoirs, mines, homes etc. Solid-state gas sensors have many advantages over the conventional analytical methods and hence are widely used. Amongst them, semiconducting metal-oxides based sensors are popular due to many advantages like low cost, small size, high sensitivity and long life. The present thesis reports a detailed work of TiO2 (Titania) thin film fabrication based on sol-gel method, study of their crystallization behavior and surface morphology, and characterizing them for alcohol sensing properties Sol-gel method is a wet chemical technique with many advantages over the conventional methods and offers a high degree of versatility to modify the film properties. Titania thin films were made with titanium isopropoxide as the precursor and ethanol and isopropanol as the solvents. Also effect of surfactants(PEG and CTAB) on the sol properties and film properties have experimentally examined. A in-house gas sensor testing setup has been designed and fabricated to characterize the sensors. Sensors with three different electrode configurations and also two different electrode material have been tested. The electrode geometry and material play a significant role on the sensing behavior and results for the same have been discussed.

Download or read book Fundamentals and Applications of Chemical Sensors written by Dennis Schuetzle and published by . This book was released on 1986 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the first comprehensive collection of articles on the fundamentals and applications of a wide variety of chemical sensors. Discusses a range of topics from the development of new sensor concepts to improvement in sensors that have been mass produced for several years. Specific types of sensors discussed include oxygen, electrochemical, microbial, drug, and glucose sensors.

Download or read book Semiconductor Gas Sensors written by Raivo Jaaniso and published by Woodhead Publishing. This book was released on 2019-09-24 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor Gas Sensors, Second Edition, summarizes recent research on basic principles, new materials and emerging technologies in this essential field. Chapters cover the foundation of the underlying principles and sensing mechanisms of gas sensors, include expanded content on gas sensing characteristics, such as response, sensitivity and cross-sensitivity, present an overview of the nanomaterials utilized for gas sensing, and review the latest applications for semiconductor gas sensors, including environmental monitoring, indoor monitoring, medical applications, CMOS integration and chemical warfare agents. This second edition has been completely updated, thus ensuring it reflects current literature and the latest materials systems and applications. - Includes an overview of key applications, with new chapters on indoor monitoring and medical applications - Reviews developments in gas sensors and sensing methods, including an expanded section on gas sensor theory - Discusses the use of nanomaterials in gas sensing, with new chapters on single-layer graphene sensors, graphene oxide sensors, printed sensors, and much more

Download or read book Synthesis Fabrication and Surface Modification of Nanocrystalline Nickel Oxide for Electronic Gas Sensors written by Amir Masoud Soleimanpour and published by . This book was released on 2013 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, metal oxide gas sensors have attracted much attention in connection with monitoring of combustible and toxic gases because of their higher sensitivity, fast response and recovery times, low power consumption, and low fabrication cost. Nickel oxide (NiO) is a wide band gap and p-type semiconductor with stable chemical and physical properties. NiO has been recognized as one of the most promising material for optical, electrical and gas sensor application owing to its electronic and catalytic properties. NiO is synthesized using different techniques, such as pulsed laser deposition, RF sputtering, electrochemical deposition and sol-gel. The focus of this research was to synthesize and characterize the gas sensing behavior of nickel oxide metal oxide gas sensors. Thin films of nickel oxide synthesized by a sol-gel method have fine nanostructured grains with a high surface to volume ratio, which is beneficial for gas sensor applications. The effect of thickness, fabricating technique, operating temperature, post laser irradiation and metallization on the gas sensing behavior of nickel oxide have been studied. The microstructure, optical and electrical properties of coated film were studied by XRD, SEM, TEM, EDAX, XPS, UV-Vis spectrometer. The gas sensing properties of NiO based sensors were studied for different explosive and hazardous gases as a function of gas concentration and operating temperature. The dependence of fabrication method, film thickness and operating temperature on the hydrogen gas sensing behavior of NiO thin films was investigated. It was observed that the samples with multi-step annealing possessed smaller grain size, higher porosity and higher gas sensing performance. The sample with lower thickness showed better gas sensing performance in all operating temperatures. Moreover, the operating temperature was an important parameter for nickel oxide thin film, and the maximum gas sensor response was recorded at 175oC for hydrogen gas. The effect of post laser irradiation on the gas sensing property of NiO was investigated using Nd:YVO4 laser with a wavelength of 532 nm in different power levels. After laser irradiation, the microstructure, crystallinity and conductivity of the thin films were changed. Results indicated that the irradiated sample with specific power showed better gas sensing performance for hydrogen. Also, the gas sensor response decreased using laser irradiation on the sample. As a result, laser irradiation is an additional tool for tuning the gas sensing behavior of nickel oxide gas sensor. Later, the nickel oxide film was tested for other reducing gases, such as CH4, NH3, and in a mixed gas environment at different operating temperatures. These measurements were conducted to study the selectivity of nickel oxide gas sensor. It was found that the NiO thin film showed a relatively high response to a low concentration of ammonia gas (25 ppm) at a relatively low operating temperature. Instead, the sample showed a relatively low response to methane gas compared to hydrogen and ammonia in the same concentration level. Besides, the gas response of the device at different operating temperature was studied for reducing gases. The film showed a maximum sensitivity for methane and hydrogen gases at 175oC, and the highest response was recorded at 150oC for ammonia gas. These findings are valuable to design selective gas sensors. Finally, Pt decorated sample was tested for various concentrations of hydrogen gas at different operating temperature. The gas sensing property of the film was improved significantly due to the catalyst effect of Pt particles on the surface of metal oxide. Pt decorated sample increased the hydrogen sensing property of nickel oxide by decreasing the energy needed for splitting H2 or O2 molecules on the surface of metal oxide. This study shows several important parameters for nickel oxide gas sensors and it is expected that these techniques can be used to improve the gas sensing performance of different metal oxide gas sensor devices in the future. Collected data at various operating temperatures and gas mixtures can be used to design more selective gas sensors. More detailed research is necessary to establish a general rule for other metal oxide thin films.

Download or read book Metal Oxide Nanostructures as Gas Sensing Devices written by G. Eranna and published by Taylor & Francis. This book was released on 2016-04-19 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxide Nanostructures as Gas Sensing Devices explores the development of an integrated micro gas sensor that is based on advanced metal oxide nanostructures and is compatible with modern semiconductor fabrication technology. This sensor can then be used to create a compact, low-power, handheld device for analyzing air ambience.The book first c

Download or read book Handbook of Gas Sensor Materials written by Ghenadii Korotcenkov and published by Springer Science & Business Media. This book was released on 2013-11-08 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two volumes of Handbook of Gas Sensor Materials provide a detailed and comprehensive account of materials for gas sensors, including the properties and relative advantages of various materials. Since these sensors can be applied for the automation of myriad industrial processes, as well as for everyday monitoring of such activities as public safety, engine performance, medical therapeutics, and in many other situations, this handbook is of great value. Gas sensor designers will find a treasure trove of material in these two books.

Download or read book Chemical Solution Deposition of Functional Oxide Thin Films written by Theodor Schneller and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 801 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first text to cover all aspects of solution processed functional oxide thin-films. Chemical Solution Deposition (CSD) comprises all solution based thin- film deposition techniques, which involve chemical reactions of precursors during the formation of the oxide films, i. e. sol-gel type routes, metallo-organic decomposition routes, hybrid routes, etc. While the development of sol-gel type processes for optical coatings on glass by silicon dioxide and titanium dioxide dates from the mid-20th century, the first CSD derived electronic oxide thin films, such as lead zirconate titanate, were prepared in the 1980’s. Since then CSD has emerged as a highly flexible and cost-effective technique for the fabrication of a very wide variety of functional oxide thin films. Application areas include, for example, integrated dielectric capacitors, ferroelectric random access memories, pyroelectric infrared detectors, piezoelectric micro-electromechanical systems, antireflective coatings, optical filters, conducting-, transparent conducting-, and superconducting layers, luminescent coatings, gas sensors, thin film solid-oxide fuel cells, and photoelectrocatalytic solar cells. In the appendix detailed “cooking recipes” for selected material systems are offered.

Download or read book Enhancement of Nanocrystalline Zinc Oxide Based Electronic Gas Sensor by Surface Modification written by Yue Hou and published by . This book was released on 2014 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing concerns of industrial safety, chemical control and environmental pollution are spurring demand for high performance gas sensors. Growing use of gas sensors is making gas sensors on demand. After decades of research and development activities, semiconductor based gas sensors are now used in a variety of applications. However, challenges still remain in the area of sensitivity, selectivity, response and recovery speeds and power consumption. Therefore, improvement of metal oxide gas sensors by the incorporation of different technology is important. In this research, modification of metal oxide semiconductor based gas sensor by impurity doping, laser irradiation, and plasma treatment was investigated. Zinc oxide (ZnO) is an n-type semiconductor with a wide direct band gap (~3.3 eV) and large binding energy (~60 meV). Due to its superior electrical properties and chemical stability, ZnO has been considered one of the most promising materials for gas sensor applications. ZnO thin films have been fabricated by different techniques, such as rf magnetron sputtering, pulsed laser deposition, molecular beam epitaxy, and sol-gel. Sol-gel is a powerful alternative for vacuum deposition. The purpose of this research was to enhance properties and gas sensor performance of nanocrystalline so-gel derived ZnO thin films via surface modification techniques. The effects of process conditions, impurity doping, laser irradiation, laser doping and plasma treatment on properties and gas sensor performance were investigated. The gas sensor performance of ZnO thin films was investigated at different operating temperatures for various reducing and oxidizing gases such as H2, NH3, CH4 and NOx. Al-doped ZnO thin films were prepared using the sol-gel process by changing the Al concentration from 0 to 5.0 at% using two different Zn precursors. It was found that 3.0 at% Al-doped ZnO films had optimum properties such as high electrical conductivity, crystallinity, high sensing response and short response time for ZnO films derived with both Zn precursors. Ga-doped ZnO thin films were also presented by changing the concentration of Ga from 0.1 to 1.0 at%. The gas sensing behavior was investigated at an operating temperature of 130oC. It was found that the 0.3 at% Ga-doped ZnO thin film sensor had more than a 40% higher sensing response and a shorter response time than the sensors made with as-deposited films. Laser irradiation was utilized as a novel heat treatment method in this dissertation. A pulsed laser system with a wavelength of 532 nm was used as the irradiation source. Laser irradiation produced two kinds of Al-doped ZnO films depending on the laser energy level. The impact of laser irradiation was also varied according to the film thickness. The Al-doped ZnO sensors exhibited enhanced sensor performance with optimum laser fluence compared with that of as-deposited sensors. The results suggested that the crystallinity of the Al-doped ZnO thin films was essential to achieve an optimum gas detection capability. A laser doping process using a pre-deposited Al precursor layer for ZnO thin films was also investigated. Plasma treatment was utilized in the research with the intention to adjust the number of intrinsic defects in ZnO films. Both O2 and H2 plasmas were carried out with the treatment time varying from 3 to 15 min. The gas sensor performance was investigated for NH3 and NOx at various concentrations. An improvement of more than 50% in sensing response was observed with the optimum treatment time for NH3 detection. The impact of H2 plasma treatment of ZnO sensors on its gas sensor performance was also studied. The selectivity was studied for a likelihood mixture of reducing gases. The results indicated that ZnO sensors had a low detection limit towards NH3. It was found that the selectivity of these reducing gases was in the order of NH3> H2> CH4. However, unless high concentration of NH3 exposure is a factor, ZnO sensors are selective respond to H2. Furthermore, the ZnO sensors are also capable of discriminating different gases such as NH3, H2, CH4 and NOx. This research involves different techniques, which have been employed on the ZnO thin film based gas sensors in order to enhance the gas sensing characteristics such as sensing response and response time. As expected, the ZnO sensors exhibited high response, short response time and decent selectivity toward target gases with optimum treatment conditions. The results also suggested that the ZnO sensors were capable of detecting ppm level gases at relatively low operating temperature range (100 ~ 200oC), which is beneficial in many applications. Therefore, these techniques can be utilized to manufacture gas sensors using metal oxide semiconductors.

Download or read book Microfabricated Systems and MEMS VI written by Peter J. Hesketh and published by The Electrochemical Society. This book was released on 2002 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Oxides in Supercapacitors written by Deepak P. Dubal and published by Elsevier. This book was released on 2017-07-10 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides in Supercapacitors addresses the fundamentals of metal oxide-based supercapacitors and provides an overview of recent advancements in this area. Metal oxides attract most of the materials scientists use due to their excellent physico-chemical properties and stability in electrochemical systems. This justification for the usage of metal oxides as electrode materials in supercapacitors is their potential to attain high capacitance at low cost. After providing the principles, the heart of the book discusses recent advances, including: binary metal oxides-based supercapacitors, nanotechnology, ternary metal oxides, polyoxometalates and hybrids. Moreover, the factors affecting the charge storage mechanism of metal oxides are explored in detail. The electrolytes, which are the soul of supercapacitors and a mostly ignored character of investigations, are also exposed in depth, as is the fabrication and design of supercapacitors and their merits and demerits. Lastly, the market status of supercapacitors and a discussion pointing out the future scope and directions of next generation metal oxides based supercapacitors is explored, making this a comprehensive book on the latest, cutting-edge research in the field. - Explores the most recent advances made in metal oxides in supercapacitors - Discusses cutting-edge nanotechnology for supercapacitors - Includes fundamental properties of metal oxides in supercapacitors that can be used to guide and promote technology development - Contains contributions from leading international scientists active in supercapacitor research and manufacturing

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2676 pages. Available in PDF, EPUB and Kindle. Book excerpt: