Дисертації з теми "TiO2 Thin Film Gas Sensors"
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Brown, J. R. "Tin oxide thin film gas sensors deposited by MOCVD." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434038.
Повний текст джерелаJin, Yoonsil. "Toxic gas sensors using thin film transistor platform at low temperature." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/46669.
Повний текст джерелаIncludes bibliographical references (leaves [71-73]).
Semiconducting metal-oxides such as SnO₂, TiO₂, ZnO and WO₃ are commonly used for gas sensing in the form of thin film resistors (TFRs) given their high sensitivity to many vapor species, simple construction and capability for miniaturization. Furthermore, they are generally more stable than polymer-based gas sensors. However, unlike polymers, metal oxide gas sensors must typically be operated between 200-400°C to insure rapid kinetics. Another problem impacting TFR performance and reproducibility is related to poorly understood substrate-semiconductor film interactions. Space charges at this heterojunction are believed to influence chemisorption on the semiconductor-gas interface, but unfortunately, in an unpredictable manner. In this study, the feasibility of employing illumination and the thin film transistor (TFT) platform as a means of reducing operation temperature was investigated on ZnO based TFTs for gas sensors applications. Response to NO₂ is observed at significantly reduced temperature. Photoconductivity measurements, performed as a function of temperature on ZnO based TFRs, indicate that this results in a photon-induced desorption process. Also, transient changes in TFT channel conductance and transistor threshold voltage are obtained with application of gate bias, suggesting that TFTs offer additional control over chemisorption at the semiconductor-gas interface.
by Yoonsil Jin.
S.M.
Rasheed, Raymond Kelvin. "New sensing materials for the detection of malodours." Thesis, University of the West of England, Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308791.
Повний текст джерелаKirchner, Patrick [Verfasser], and Michael [Akademischer Betreuer] Keusgen. "Thin-film calorimetric gas sensors for hydrogen peroxide monitoring in aseptic food processes / Patrick Kirchner. Betreuer: Michael Keusgen." Marburg : Philipps-Universität Marburg, 2013. http://d-nb.info/1038786169/34.
Повний текст джерелаZhang, Jian. "Zeolite Thin Film-Fiber Integrated Optical Sensors for Highly Sensitive Detection of Chemicals in Gas and Liquid Phases." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195680520.
Повний текст джерелаAbhijith, N. "Semi Conducting Metal Oxide Gas Sensors: Development And Related Instrumentation." Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/281.
Повний текст джерелаFisher, Brian. "Surface Acoustic Wave (SAW) Cryogenic Liquid and Hydrogen Gas Sensors." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5208.
Повний текст джерелаPh.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
Kitenge, Denis. "Optical detection of CO and H2 based on surface plasmon resonance with Ag-YSZ, Au and Ag-Cu nanoparticle films." Scholar Commons, 2009. http://scholarcommons.usf.edu/etd/2047.
Повний текст джерелаCavallari, Marco Roberto. "Filmes de poli (3-hexiltiofeno) (P3HT) para transistores de filmes finos orgânicos utilizados como sensores." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-29122014-165104/.
Повний текст джерелаResearch on organic electronics, compared to conventional silicon-based microelectronics, is necessary as it offers plenty of semiconductors and low-cost deposition techniques that can be performed over wide surfaces. Organic Thin-Film Transistors (OTFTs) are the fundamental unity in electronic circuits and, usually, display the metal insulator semiconductor field-effect transistor (MISFET) structure. OTFTs can be processed over cheap plastic substrates and integrate a high number of applications as: flexible displays, radio frequency identification tags, textile electronics and sensors (e.g. chemical and biological compounds). Nowadays, consumers demand portable and low-cost electronic devices, mainly as sensors for in-situ medical and veterinarian diagnosis. The most widely used OTFT structure in sensing is the bottom-gate/bottom-contact FET over highly-doped silicon substrates and inorganic dielectrics. Polymers as poly(3-hexylthiophene) (P3HT) have found increasing acceptance by the scientific community, attesting their potential as semiconductors for commercial applications. In this context, the thesis lies in the development of organic transistors based in P3HT polymer for the detection of vapor-phase compounds. This study begins with transistor performance optimization through changes in dielectric and semiconductor processing. Thin-film thickness and P3HT cast solution drying time are the main studied parameters. It involves also the understanding of device performance degradation when exposed to atmosphere and under bias stress, before finally mapping sensitivity and specificity against gaseous analytes. P3HT-based sensors are potentially interesting for ammonia, ketones and organochlorides detection. Other polymeric semiconductors may be necessary to increase specificity against water steam and alcohol analytes.
Raval, Mehul Chandrakant. "Sol-Gel Derived Titania Films And Their Potential Application As Gas Sensor." Thesis, 2008. http://hdl.handle.net/2005/930.
Повний текст джерелаSu, Wei-Chi, and 蘇威吉. "Design of Organic thin-film gas sensors." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/32179109779481572616.
Повний текст джерела國防大學理工學院
光電工程碩士班
97
The design of gas sensor with array organic thin films is discussed. Resistivity change of phenylene films from absorbing to-be-measured gas molecules can help distinguish the pernicious gases from others. This research is aimed at development of signal-acquiring circuit, control and identification software. We have finished designing the portable gas sensor, building the prototype, and creating the useful database to identify industrial pernicious gas such as ethyl alcohol ethanol, methyl ethyl ketene, trichloromethane, tetrahydrofuran and xylene. So far it can distinguish five gases described above real-time; besides, in the future it can also utilized to detect and analyze other pernicious gases through training.
Li, ZHE-MING, and 李哲名. "Ozone gas sensor deposed of TiO2/SnO2Composite thin films by RF magnetron sputtering." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54539648290393757016.
Повний текст джерела靜宜大學
應用化學研究所
99
SnO2 thin films have many excellent properties which used as a gas sensor material.TiO2 photocatalyst material is used as a photolysis. photocatalyst have advantages of high activity、good stability、non-toxic and low cost. However,UV radiation resulting from the electron and hole addition to photocatalytic effect,will also produce another effect of the binding reaction and reduce the photocatalyst. We used the heterogeneous bonding film to increase electron and hole in the life cycle. This study combines two materials using RF magnetron sputtering, the sensor material will be covered in a web printing gold electrode on alumina substrate as a ozone sensor. This coating method can not only material were not easily fall off, but also fewer steps to the powder recovery, achieving environmental protection. In the experiment, change the deposition parameters as substrate temperature and working pressure , and film thickness change to get different kinds of performance films. We used X-ray powder diffraction (XRD) to analyze the structure;By scanning electron microscopy (SEM) and atomic force microscope (AFM) to observe the film surface morphology and roughness;UV (365 nm) surface after exposure and access of ozone gas through the conversion of electrical signals to achieve the effect of the calculation on the sensor gas sensor. Results showed that the sputtering power at 100 W, substrate temperature of 100 ℃, working pressure 10 mtorr, the sensor has the best effect. The crystalline phase of TiO2, Anatase phase has a larger band gap than the Rutile phase, and the electron - hole with a long life cycle, it results in the sensor would be better. Sensors sensing different gases, the sensor can be found in this study has good selectivity. TiO2/SnO2 bilayers because of its amorphous structure with short-range order of the Anatase phase spread , Compared with TiO2-SnO2 co-deposited thin films which have Rutile Phase,sensing effects will be better. Also proved that film can effectively reduce the heterogeneity of bonding electron and hole recombination, and greatly enhance the effect of sensing. Order to further enhance sensor selectivity, combined with semiconductor and MEMS technology, manufacturing composite membrane electrode sensors and changing the material of the stack, will help to improve sensor performance, and shorten the reaction time.
Liu, Yung-Chen, and 劉永振. "Study on Barium Strontium Titanate thin film gas sensors." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/63197803170200803187.
Повний текст джерела國立雲林科技大學
電子與資訊工程研究所碩士班
90
In this thesis, the solution of the ferroelectric materials, Barium Strontium Titanate(BaxSr1-xTiO3, BST) were prepared and deposited on SiO2/p-Si(100) substrate as the sensing layer of gas sensor by using sol-gel spin coating technique. In order to increase the sensitivity, the catalyst, Pd, was added in the sensor. The structure of the gas sensor is metal/ferroelectrics thin-film/insulator/semiconductor (MFIS). The current-voltage measurements were made by adding oxygen gas and carbon monoxide (CO) into the testing chamber as sensing gas for sensors processing under different annealed temperature and time. We deploied four kinds of different Barium(Ba) and Strontium(Sr) ratio of the Barium Strontium Titanate(BaxSr1-xTiO3) solutions by sol-gel method, where x is 1, 0.8, 0.7 and 0.5. The experiments were shown that the senseing device wasn’t suitable for long-time annealing . Experimental results clearly show that the BaTiO3 thin film had a optimum voltage shift at 1000 ppm oxygen and carbon monoxide (CO) gas. And the Ba0.7Sr0.3TiO3 thin film only detected oxygen gas that had the good gas sensitivity, so selectivity was optimum. Experimental results show that the response time of the BaTiO3 thin film to gas concentration that was short than others. BST thin films would form perovskite phase after thermal annealing treatment upward 450 ℃ by XRD measurement. AFM measurements BST thin films could decrease the surface roughness under low temperature and short time of thermal annealing treatment, but the surface roughness increase after high temperature of thermal annealing treatment .
Wu, Chang-Yeh, and 吳昶燁. "Study on Arrayed Potassium Sensors Based on Sputtering TiO2 Thin Film." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/50507378420681173502.
Повний текст джерела華梵大學
電子工程學系碩士班
97
In this thesis, sputter technology was used to deposit titanium oxide (TiO2) membrane on Indium tin oxide (ITO/glass) substrate to fabricate pH sensors and Potentiometric potassium sensors. The sensitivity was between 42.51 and 52.5 mV/pH when the buffer solution was between pH2 and pH12, providing good linearity and sensitivity. The potentiometric potassium sensors on TiO2/ITO were fabricated by Poly (vinyl chloride) carboxylated (PVC-COOH), plasticizer Bis (2-ethylhexyl) sebacate (DOS), Potassium Ionophore Valinomycin and K-TpClPB. After six repeated measurements, detection limit was 1×10-6M ,the sensitivity is about 49.76mV/decade for the potassium solutions ranging from 1M to 1×10-6M. The advantage of arrayed-sensors is to enhance signal to noise ratio (S/N) and have high accuracy because of eliminating unreasonable values with read-out circuit. In this study 1×4 linear arrays was prepared to detect potassium using parallel-measurement, the corresponding sensitivity is between 50 and 51.8mV/decade. The Hysteresis and drift of arrayed-sensor were better than that of single-sensor. Otherwise the 1×4 arrayed-sensor used parallel measurement comparing with 1×4 arrayed-sensor used average measurement have more stable output voltage and promote hysteresis.
Kiether, William Jay. "Application of sculptured thin film technology to metal oxide gas sensors." 2007. http://www.lib.ncsu.edu/theses/available/etd-03262007-123607/unrestricted/etd.pdf.
Повний текст джерелаChen, Kuan-Ting, and 陳冠廷. "The Study of ZnO thin film gas sensors activation by UV light." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/65272214137911850271.
Повний текст джерела國立高雄大學
電機工程學系--先進電子構裝技術產業研發碩
97
In this dissertation, the nano structured Zinc Oxide (ZnO) was achieved by the thermally evaporated Zinc (Zn) on sapphire substrate followed by suitable thermal treatment. The resistance for the film was studied under different oxygen and nitrogen gas conditions and ultra violet light illumination. The response and recovery time for the film with different conditions was studied. The mechanism was discussed with the surface morphology study and the corresponded physical models. Under the pulse light modulation and the followed signal process, applications with short response and recovery time can be achieved.
Niu, Jing-Shiuan, and 牛敬璿. "Applications of Al2O3 Thin Film on Field-Effect Transistors and Gas Sensors." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/f52ptd.
Повний текст джерела國立高雄師範大學
電子工程學系
107
In this dissertation, a series of AlGaN/AlN/GaN high electron mobility transistors (HEMTs) on silicon substrates and Al2O3 thin film-based resistor-type gas sensors are successfully fabricated and studied. We first fabricated AlGaN/AlN/GaN HEMTs with Ni/Au gate electrode and focused on their properties. Then, nickel oxide (NiO) and aluminum oxide (Al2O3) layers are deposited by radio-frequency (RF) sputtering as gate oxide layers, respectively. Under the optimal process conditions, the improved device performance of the metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) has been achieved. The DC characteristics of the MOS-HEMT with NiO and Al2O3 gate oxide layers include maximum drain-to-source saturation current densities IDS, max of 626.5 and 692.0 mA/mm, maximum transconductances gm, max of 87.6 and 94.2 mS/mm, gate-to-drain leakage currents IGD at VGD = -40 V of 1.47 10-7 and 8.21 10-11 mA/mm, threshold voltages Vth of -3.48 and -3.45 V, gate voltage swings GVS of 2.88 and 3.08 V, respectively. Due to the high dielectric constant, the gate dielectric layers can decrease the surface state density and drain-to-source resistance to cause sheet carrier concentration to increase. Second, in order to improve the stability of the gate electrode under the thermal effects, we used palladium (Pd) metal to replace Ni/Au metal. After that, we inserted Al2O3 as the gate dielectric layer to develop a MOS-HEMT. The DC characteristics of the MOS-HEMT and MS-HEMT include IDS, max of 624.9 and 548.1 mA/mm, gm, max of 84.2 and 78.2 mS/mm, IGD at VGD = -40 V of 7.71 10-11 and 3.65 10-6 mA/mm, Vth of -3.13 and -4.28 V, GVS of 3.12 and 3.04 V, respectively. The experimental results show that the use of Pd metal as the gate electrode of HEMT has better thermal stability, allowing devices to obtain a larger operating range. Then, five kinds of devices with the different metal gate electrodes and gate dielectric layers were fabricated and investigated. Experimentally, the device with the Pd gate electrode had lower gate leakage current and larger gate voltage swings than Ni/Au gate-electrode devices because Pd metal exhibits lower diffusion and higher thermal stability than Ni. Moreover, the gate dielectric layer can reduce interface charges and suppress gate leakage current to improve the device characteristics and reliability. Finally, we deposited Al2O3 thin film on the interdigitated electrodes to fabricate a resistor-type gas sensor, which Al2O3 thin film is the sensing region. We used two different catalytic metals and structures. The first structure was the Pd nanoparticles (NPs)/Pd film/Al2O3 film and the second structure was the Pt NPs/Pt film/Al2O3 film. The experimental results showed that the sensing response ratios of the first structure are 14.4% in 1000 ppm H2/air and 15% in 20 ppm HCOH/air. The sensing response ratios are 8.2% in 1000 ppm NH3/air and -9.5% in 100 ppm NO2/air for the second structure, respectively.
Singh, Inderjit. "Gas Sensors - Micro-Heater Designs And Studies On Sensor Film Deposition." Thesis, 2006. http://hdl.handle.net/2005/393.
Повний текст джерелаChang, Yi-Po, and 張一博. "In-situ photopolymerization of nanopowder TiO2/polypyrrole nanocomposite thin film combined with QCM as low humidity sensors." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74456167786064087305.
Повний текст джерела中國文化大學
應用化學研究所
96
Novel low humidity sensors were fabricated through in-situ photopolymerization of polypyrrole/TiO2 nanoparticles (PPy/TiO2 NPs) composite thin films on quartz-crystal microbalance (QCM). The characterizations of the thin films were analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The sensitivity increased with increasing the doping amount of TiO2 NPs. The PPy/50 wt.% of TiO2 NPs composite thin films showed excellent sensitivity (0.0246 -Hz/ppmv at 171.12 ppmv), linearity (Rsqr=0.9576) and fast response time (12 s at 55.0 ppmv). The low humidity sensing mechanism was discussed in terms of surface texture and nanostructured morphology of the composite materials. Moreover, based on the adsorption dynamic analysis, the association constant of water vapor molecules with PPy and PPy/50 wt.% of TiO2 NPs composite thin films were estimated to be 81.609 and 227.867 M-1, respectively, thus explaining the effect of adding 50 wt.% TiO2 NPs into PPy in the increased sensitivity of low humidity sensing with larger association constant.
Ail, Ujwala. "Thin Film Semiconducting Metal Oxides By Nebulized Spray Pyrolysis And MOCVD, For Gas-Sensing Applications." Thesis, 2009. http://etd.iisc.ernet.in/handle/2005/1970.
Повний текст джерела"Improving the Sensing Performance of Semiconductor Metal Oxide Gas Sensors through Composition and Nanostructure Design." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.62901.
Повний текст джерелаDissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2020
Parmar, Mitesh Ramanbhai. "Development And Performance Study Of Nanostructured Metal Oxide Gas Sensor." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2425.
Повний текст джерелаMishra, Rahul. "Synthesis And Characterization Of Metal-Oxide Thin Film With Noble Metal Nano-Particles As Additives For Gas Sensing Application." Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1209.
Повний текст джерелаCHANG, JUI-LIN, and 張瑞麟. "Highly Sensitive Photo-activated Sensors Based on Iron, Nitrogen Co-modified Peroxo Titanic Thin Film for Gas and Humidity Sensing." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/68423893466455062767.
Повний текст джерела國立臺灣大學
電子工程學研究所
102
Gas sensors can be utilized to detect volatile organic compounds (VOCs) or humidity. Volatile organic compound sensors and humidity sensors can be applied in many fields. In this research, we synthesized a new material consisting of iron and nitrogen co-modified peroxo titanium oxide, for the VOCs and humidity sensing applications. We developed a sol-gel technology to synthesize iron, nitrogen co-modified peroxo titanium oxide and the ratio of iron, nitrogen and titanium can be adjuted. UV light was used to improve the sensing performance of humidity and VOCs. This sensor has great response to humidity and the impedance value varies a lot with different frequencies. When using a impedance analyzer to measure the impedance change, the impedance change spanned almost five orders of magnitude during the measurement of relative humidity (RH) from 11%-75% under 100Hz. On the other hand, the sensor can measure the methanol and toluene from 6000 to 10000 ppm. We proved that our sensors have good improvements after illuminating 365nm ultraviolet light for 15 minutes. Our sensors have good selectivity between methanol and ethanol . Our sensors’ response time and recovery time are less than 2s to water, and approximately 20s to VOCs. Because the material surface is hydrophilic so water molecules can easily be adsorbed. It is believed that VOCs have to compete to the water molecules for reaction sites and thus the response time is slower than water.
Shih, Wei-Tao, and 施維濤. "A Comparative Study of the Electrical Characteristics between Poly-silicon Thin Film Transistors and Nano-wire Field Effect Transistors for Gas Sensors." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/09144214867944270407.
Повний текст джерела國立交通大學
電子工程系所
98
In this thesis, we utilize planar and nano-wire poly-silicon thin film transistors for gas sensing measurements. We investigate their electrical characteristics under various environments, such as normal ambient, nitrogen ambient, and vacuum, and study the effects of adding moisture and ammonia on device performance. The sensitivity of the devices to the variation of environment is also found to be very strongly dependent on the channel thickness. A model considering the interaction of H-related species in the air with the poly-Si is proposed to explain the observed results.
Velmathi, G. "Integrated Gas Sensor - Studies On Sensing Film Deposition, Microheater Design And Fabrication, Interface Electronics Design And Testing." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2457.
Повний текст джерелаChuang, Yuh-Suan, and 莊育軒. "Flexible gas sensors fabricated by layer-by-layer self-assembly thin film of multi-walled carbon nanotubes and modified with metal catalyst nanoparticles." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/28940562692038425198.
Повний текст джерела中國文化大學
應用化學研究所
98
A novel flexible H2 gas sensor was fabricated by the layer-by-layer (LBL) self-assembly of thin film surface-oxidized multi-walled nanotubes (MWCNTs) on a polyester (PET) substrate. Then, a Pd-based complex was self-assembled in situ on the as-prepared MWCNTs thin film, which was reduced to form an MWCNT-Pd thin film. The thin films were characterized by scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The gas sensing properties, such as strength of the response, sensing linearity, reproducibility, response time, recovery time, cross-sensitivity effects and long-term stability were also investigated. The flexible H2 gas sensor exhibited a strong response that was comparable to or even greater than that of sensors that were fabricated on rigid substrate at room temperature.
Jia-HuoLuo and 羅嘉和. "The Development of Low Temperature Poly Silicon (LTPS) Thin Film Schottky Diode Type CO Gas Sensors with Various Structures Metal Oxide on Glass Substrate." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82245501857038607364.
Повний текст джерелаKiruba, M. S. "Fabrication and Optimization of Yttria Stabilized Zirconia Thinfilms towards the Development of Electrochemical Gas Sensor." Thesis, 2016. http://hdl.handle.net/2005/3059.
Повний текст джерелаAnuradha, S. "Development Of A Tin Oxide Based Thermoelectric Gas Sensor For Volatile Organic Compounds." Thesis, 2007. http://hdl.handle.net/2005/623.
Повний текст джерелаKamble, Vinayak Bhanudas. "Studies on Effect of Defect Doping and Additives on Cr2O3 and SnO2 Based Metal Oxide Semiconductor Gas Sensors." Thesis, 2014. http://hdl.handle.net/2005/3258.
Повний текст джерелаSree, Rama Murthy A. "Physicochemical Characterization and Gas Sensing Studies of Cr1-xFexNbO4 and Application of Principal Component Analysis." Thesis, 2016. http://hdl.handle.net/2005/3215.
Повний текст джерелаJayaraman, Balaji. "Modular Design Of Microheaters, Signal Conditioning ASIC And ZnO Transducer For Gas Sensor System Platform." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2115.
Повний текст джерела