Download or read book Application of Sculptured Thin Film Technology to Metal Oxide Gas Sensors written by William Jay Kiether and published by . This book was released on 2007 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: A conductive MOS sensor was designed based on an anatase chevron formation. Following the fabrication of a sensor test chamber, the sensor response was characterized versus temperature for inert, oxidizing, and reducing atmospheres.

Download or read book Application of Sculptured Thin Film Technology to Metal Oxide Gas Sensors written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main goal of this research has been the application of glancing angle deposition (GLAD) techniques to create highly porous sculptured thin films (STF) structures for use as gas sensors. The glancing angle technique utilizes physical vapor depositions at highly oblique (>70 & deg;) angles of incidence to form porous film structures. Process conditions including the deposition rate, rotation speed, and flux angle were investigated to produce pillar and chevron formations. Control of the anatase/rutile percentages in TiO2 gas sensors is critical for design and development. Thin films were deposited using reactive e-beam evaporation with a titanium source melt at various partial pressures of oxygen and argon. Post deposition anneal studies were conducted in air from 150-900 & deg;C. The combination of reactive evaporation at high oxygen partial pressures and low temperature (150 & deg;C) anneals in air formed films with the highest percentage of anatase. Depositions at lower oxygen partial pressures yielded films with a higher percentage of rutile, which supports the role of oxygen vacancies as nucleation centers for the anatase to rutile transformation. Higher temperature annealing produced rutile films as expected from the thermodynamics of the TiO2 system. After the formation of anatase STF structures, the films displayed a high degree of temperature stability with subsequent annealing. Anatase films structures were still evident even after annealing at 1200 & deg;C in air. The GLAD technique produces films with preferred crystal orientations which differ based on the deposition angle. A series of experiments looked at the effect of the angle of incidence, the deposition conditions, and the substrate material on the crystal structure of the STF structures. The titanium films did show a dependence of the crystalline structure on the angle of incidence for both as-deposited films and after oxidation at 900 & deg;C in air. A conductive MOS sensor was designed based on.

Download or read book Gas Sensors Based on Conducting Metal Oxides written by Nicolae Barsan and published by Elsevier. This book was released on 2018-10-17 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas Sensors Based on Conducting Metal Oxides: Basic Understanding, Technology and Applications focuses on two distinct types of gas sensors based on conducting metal oxides. Ion conduction, applied in so-called solid-state electrolytic sensors for one, and electronic conduction used in semiconductivity gas sensors for the other. The well-known ?–probe, a key component to optimize combustion in car engines, is an example of the former type, and the in-cabin car air-quality control SnO2 and WO2 sensor array stands for the semiconductivity type. Chapters cover basic aspects of functioning principles and describe the technologies and challenges of present and future sensors. - Provides reader background and context on sensors, principles, fabrication and applications - Includes chapters on specific technological applications, such as exhaust sensors, environmental sensors, explosive gases alarms and more - Presents a structured presentation that allows for quick reference of vital information

Download or read book Transition Metal Oxide Thin Film Based Chromogenics and Devices written by Pandurang Ashrit and published by Elsevier. This book was released on 2017-05-18 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: The phase transition and the reversible optical and electrical switching that occur in chromogenic materials under the influence of external forces such as heat, light, and electric field are topics of enormous scientific interest. Transition Metal Oxide Thin Film–Based Chromogenics and Devices discusses experimental and theoretical developments in the field of chromogenics based on the transition metal oxide (TMO) thin films. Understanding the relationship between the switching properties of TMO materials and their nanostructure is of paramount importance in developing efficient chromogenic devices. The tailoring of these switching behaviors is afforded detailed coverage in this book, alongside in-depth discussion of a range of chromogenic materials and devices, including photochromics, thermochromics, and electrochromics. Transition Metal Oxide Thin Film–Based Chromogenics and Devices covers both the theoretical aspects of TMO thin film–based chromogenics and their engineering applications in device construction. Academics and professionals in the fields of materials science and optics will find this book to be a key resource, whether their focus is low-dimension materials, light-materials interactions, or device development. - Enables researchers to keep up with developments in thin film–based chromogenics - Provides detailed coverage of the switching mechanism of the various TMO thin films to assist readers in developing more efficient devices - Offers in-depth discussion of a range of chromogenic materials and devices, including thermochromics, photochromics, and electrochromics

Download or read book Semiconducting Metal Oxides for Gas Sensing written by Yonghui Deng and published by Springer Nature. This book was released on 2023-08-23 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of this book focuses on the synthesis, design, and application of semiconducting metal oxides as gas sensing materials, including the gas sensing mechanism, and modification methods for sensing materials, while also providing a comprehensive introduction to semiconductor gas sensing devices. As an essential part of IoT (Internet of things), gas sensors have shown great significance and promising prospects. Therefore, studies on functional mesoporous metal oxides, one of the most important gas sensing materials based on their unique Knudsen diffusion behavior and tailored pore structure, have increasingly attracted attention from various disciplines. The book offers a valuable reference guide to metal oxide gas sensing materials for undergraduate and graduate students alike. It will also benefit all researchers who are involved in synthesis and gas sensing of metal oxides nanomaterials with relevant frontier theories and concepts. Engineers working on research and development of semiconductor gas sensors will also find some new ideas for sensor design.

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 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 Complex and Composite Metal Oxides for Gas VOC and Humidity Sensors Volume 2 written by Bal Chandra Yadav and published by Elsevier. This book was released on 2024-04-01 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approx.530 pages Provides an overview of the material preparation and synthesis strategies of metal oxide composite and metal oxide hybrid materials for use in gas and humidity sensors Reviews emerging advanced metal oxide materials such as perovskites, spinel ferrites, and quaternary materials for gas and VOC sensors Discusses the potential opportunities and challenges to be circumvented in the use of metal oxide materials to enable new sensor technologies

Download or read book Fabrication and Testing of Doped Metal Oxide Thin Films for Gas Sensing Applications written by Kevin M. Dwane and published by . This book was released on 2000 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Integrated Thin Film Metal Oxide Gas Sensor Arrays with Application to Monitoring of Organic Vapors written by Xiaodong Wang and published by . This book was released on 1994 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Structure Surface Properties and Gas Sensor Applications of Thermoelectric Metal Oxide Thin Films written by Gavin D'Arcy and published by . This book was released on 2002 with total page 486 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 A Review on Metal Oxide Graphene Derivative Nano Composite Thin Film Gas Sensors written by Arnab Hazra and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the available commercial solid-state gas/vapor sensors are based on metal oxide semiconductors. Metal oxides (MOs) change their conductivity while exposed to gas or vapors ambient can be utilized as gas or vapor sensing materials. In recent days, graphene has attracted tremendous attention owing to its two-dimensional structure with an extremely high surface to volume ratio, electron mobility, and thermal conductivity. However, intrinsic graphene is relatively inefficient for the adsorption of gas/vapor molecules. In this regard, graphene oxide (GO) and reduced graphene oxide (rGO), which are graphene species functionalized with different oxygen groups that offer a higher amount of adsorption sites improving the sensitivity of the film. Up to now, many research groups across the globe have reported the promising performance towards gas detection using various GO/rGO-metal oxide nanocomposites. This chapter reviews the composites of graphene oxide or reduced graphene oxide and metal oxides in nanoscale dimensions (0-D, 1-D, 2-D, and 3-D) for gas sensing applications considering two specific focus areas, that is, synthesis of nanocomposites and performance assessment for gas/vapor sensing.

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 Processing microstructure property Relationships of Tin Oxide Thin Films for Gas Sensor Applications written by Li Fu and published by . This book was released on 2000 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Nano crystalline Metal Oxide Thin Films for Gas Sensors written by Dennis James Wagner and published by . This book was released on 2006 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: