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1
Zhou, Jianming. "Indium tin oxide (ITO) deposition, patterning, and Schottky contact fabrication /." LInk to online version, 2006. https://ritdml.rit.edu/dspace/handle/1850/1717.
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Yavas, Hakan. "Development Of Indium Tin Oxide (ito) Nanoparticle Incorporated Transparent Conductive Oxide Thin Films." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614475/index.pdf.
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Indium tin oxide (ITO) thin films have been used as transparent electrodes in many technological applications such as display panels, solar cells, touch screens and electrochromic devices. Commercial grade ITO thin films are usually deposited by sputtering. Solution-based coating methods, such as sol-gel however, can be simple and economic alternative method for obtaining oxide films and also ITO. In this thesis, &ldquoITO sols&rdquo
and &ldquo
ITO nanoparticle-incorporated hybrid ITO coating sols&rdquo
were prepared using indium chloride (InCl3
3
Carter, Chet. "Modification of Indium-Tin Oxide Surfaces: Enhancement of Solution Electron Transfer Rates and Efficiencies of Organic Thin-Layer Devices." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195405.
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This dissertation has focused on the study of the ITO/organic heterojunction and the chemistries therein, it proposes appropriate strategies that enhance the interfacial physical and electronic properties for charge injection with application to organic thin-layer devices. We focused on four major aspects of this work: i) To characterize the ITO surface and chemistries that may be pertinent to interaction with adjacent organic layers in a device configuration. This developed a working model of surface and provided a foundation for modification strategies. Characterization of the electronic properties of the surface indicate less than 5% of the geometrical surface is responsible for the bulk of current flow while the rest is electrically inactive. ii) To determine the extent to which these chemistries are variable and propose circumstances where compositional changes can occur. It is shown that the surface chemistry of ITO is heterogeneous and possible very dynamic with respect to the surrounding environment. iii) To propose a strategy for modification of the interface. Modification of ITO surfaces by small molecules containing carboxylic acid functionalities is investigated. Enhancements in the electron transfer rate coefficient were realized after modification of the ITO electrode. The enhancements are found to stem from a light etching mechanism. Additionally, an elecro-catalytic effect was observed with some of the modifiers. iv) Apply these modifications to organic light emitting diodes (OLEDs) and organic photovoltaic devices (OPVs). Enhancements seen in solution electrochemical experiments are indicative of the enhancements seen for solid state devices. Modifications resulted in substantially lower leakage currents (3 orders of magnitude in some cases) as well as nearly doubling the efficiency.An additional chapter describes the creation and characterization of electrochemically grown polymer nano-structures based on blazed angle diffraction gratings. The discussion details the micro-contact printing process and the electro-catalytic growth of the conductive polymers PANI and PEDOT to form diffraction grating structures in their own right. The resulting diffraction efficiency of these structures is shown to be sensitive to environmental conditions outlining possible uses as chemical sensors. This is demonstrated by utilizing these structures as working pH and potentiometric sensors based on the changing diffraction efficiency.
4
Samadi, Khoshkhoo Mahdi [Verfasser], and Marcus [Akademischer Betreuer] Scheele. "Tin-doped Indium Oxide (ITO) Nanocrystal Superlattices (Surface Chemistry, Charge Transport, and Sensing Applications) / Mahdi Samadi Khoshkhoo ; Betreuer: Marcus Scheele." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1198973072/34.
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5
Salehi, Alireza. "Radiation and thermal treatment of indium tin oxide (ITO) films and rectifying contacts." Thesis, Cardiff University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388426.
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6
Reed, Amber Nicole. "Characterization of Inert Gas RF Plasma-Treated Indium Tin Oxide Thin Films Deposited Via Pulsed DC Magnetron Sputtering." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1221763086.
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7
Saim, Hashim B. "A study of thick films of indium-tin-oxide (ITO) and the feasibility of using ITO for fabricating photovoltaic cells." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/14150.
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Thin films of In203-Sn02 transparent semiconducting oxides (ITO) have been prepared by conventional thick-film method normally employed in microelectronics technology. When fired at approximately 650 C in a continuous air flow, a continuous thick-film of the semiconducting oxides (about 3000~ thick) is obtained. The sheet resistance of the as-deposited film is about 6kQ/sq. which can be reduced to about 300 Q/sq. upon heat o -3 treatment at 300 C in a vacuum of 10 -3 torr. A slight increase of the sheet resistance to about 1 kQ/sq. occurs on ageing at ambient atmospheres for a few days. It is thought that the origin of the conductivity in the as-deposited films is due to the presence of defects resulting from the non-stoichimetric composition of the material - i.e. oxygen vacancies. and/or intestitial tin ions. The remarkable increase in conductivity when the sample is heated in a vacuum is a result of an increase in the amount of native defects from shallow donor levels in the tin-oxide. At ambient atmosphere, the film loses tin due to gradual oxidation process which again leads to an increase in resistivity. The Hall effects measurements shows that changes due to annealing are caused primarily by change in mobility, and a slight change in carrier concentration. Vacuum annealing also eliminates the effects of annealing in air. This rules out any structural changes in the film due to annealing Nature of the annealing characteristics shows that the presence of oxygen is the cause of the changes in electrical properties. Structural studies show that the films are polycrystalline with crystal sizes of 100-200 R. There is no obvious change in crystal sizes due to 11 annealing process. Electron diffraction studies also show no obvious change due to the annealing process. This, together with the vacuum annealing and mobility studies might suggest that the conductivity in the films is due to non-stoichiometric effects. Auger electron spectroscopy (which allows accurate compositional analysis) and in-depth profiling of the elements in the film was carried out. The studies show that there is a slight increase in the In/O and Sn/O ratio for the annealed films compared to the as-deposited films. All the samples show light transmissivity in the visible region of the spectrum. The fundamental absorption edge appears near 3000R which corresponds to an optical band-gap of ~4.0eV. The fundamental optical absorption edge shifts slightly towards the lower wavelength for the more conductive samples. This shift is thought to be due to Burstein shift. There is no remarkable absorption observed up to about 2pm for the unfired and unannealed films. For the annealed films however, there is an increase in absorption as the wavelength increases, possibly due to free carrier absorption. Although these results do not indicate conductivity and mobility as high as that obtained by using thin-film techniques, a feasibility study has been undertaken to fabricate heterojunction solar cells (HJSC's) of ITO-SiO -Si (single crystals). x In this structure, the ITO thick film acts not only as a conducting surface layer that induces the SIS junction but also acts as an antireflection coating. The experimental results on the working cells have shown a V = 400 mV, and J = 0.5 mA/cm2 , cc Sc and efficiency of 2 ~ 0.2% under a total insulation of = 800 W/m. The dark and illuminated I-V characteristics have been compared with published SIS solar cell data and attempts have been made to explain the mechanism of the cells.
8
Capozzi, Charles J. "Controlled self-assembly of ito nanoparticles into aggregate wire structures in pmma-ito nanocomposites." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28277.
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Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009.Committee Chair: Gerhardt, Rosario; Engineering: Dr. Arun M. Gokhale; Engineering: Dr. Preet Singh; Engineering: Dr. Mohan Srinivasarao; Engineering: Dr. Meisha Shofner.
9
McQueen, Winckler Jane. "The influence of fabrication and radiation on the structure and performance of the indium tin oxide/ indium phosphide (ITO/InP) solar cell." Thesis, Open University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316719.
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10
Boyea, John M. "Polystyrene composites filled with multi-wall carbon nanotubes and indium tin oxide nanopowders: properties, fabrication, characterization." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34813.
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This research was designed to fabricate and characterize novel polyhedral phase segregated microstructures of polystyrene (PS)-matrix composites filled with multi-walled carbon nanotubes (MWNT) and indium tin oxide (ITO) nanopowders. PS-composites were compression molded with MWNT and ITO separately first. The resulting composites were conducting, and remained optically transparent. Mixtures of MWNT and ITO were then used to form mixed ITO/MWNT PS-composites in order to optimize their transparency and conductivity. This was achieved by fabricating composites with varying concentrations of fillers. Impedance spectroscopy was used to characterize the electrical properties of the PS-composites. Optical properties were characterized by measuring the transmission of light through the PS-composite in the visible light spectrum using a spectrophotometer. The electrical properties and microstructural attributes of the fillers used were also characterized. The main objective of the project was to understand the relationships between the structural, electrical, and optical properties of the PS-composites. The resistivity of PS-composites filled with MWNT ranged from 105 to 1013 Ω cm for samples with 0.007 to 0.9 vol% MWNT. The resistivity of PS-composites filled with ITO ranged from 107 to 1013 Ω cm for PS-composites with 0.034 to 0.86 vol% ITO. PS/ITO composites had a percolation threshold of 0.15, 0.25, or 0.3 phr ITO, depending on the type of ITO used in the composite. The percolation threshold of PS/MWNT composites was found to be 0.01 phr MWNT. Mixed ITO/MWNT PS-composites were already percolated, the concentrations investigated in
xv ii
this study were already above the percolation threshold of these composites. A time dependence on impedance was found for PS-composites filled with MWNT. As time increases there is a decrease in impedance, and in some cases also a dependence on voltage. All PS-composites showed a dependence on the microstructure of the PS matrix and the filler material. The resistivity and percolation threshold were lower for PS/MWNT composites than PS/ITO composites due to the difference in filler size and aspect ratio, since MWNT have a smaller size. The orientation of PS grains with respect to neighboring grains was found to affect the resistivity of PS/MWNT. PS/MWNT composites with preferentially oriented PS grains were found to have a lower resistivity. Mixed ITO/MWNT PS-composites with the right filler concentrations were able to maintain transmission while decreasing resistivity. The fracture surface of fractured PS-composites prepared in this work indicated that there was bonding between adjacent PS-grains. From this work, it can be concluded that large grain hybrid ITO/MWNT PS-composites provide insight into the effect of combining nanometer sized filler materials together in a polymer matrix on the resultant structural, electrical, and optical properties of the composite. In the future, it is recommended that this study be used to aid research in flexible transparent conducting electrodes using a polymer matrix and hybrid/mixed nanometer sized conducting fillers.
11
Joshi, Salil Mohan. "Effect of heat and plasma treatments on the electrical and optical properties of colloidal indium tin oxide films." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52170.
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The research presented in this dissertation explores the possibility of using colloidal indium tin oxide (ITO) nanoparticle solutions to direct write transparent conducting coatings (TCCs), as an alternative route for TCC fabrication. ITO nanoparticles with narrow size distribution of 5-7 nm were synthesized using a non-aqueous synthesis technique, and fabricated into films using spin coating on substrates made from glass and fused quartz. The as-coated films were very transparent (>95% transmittance), but highly resistive, with sheet resistances around 10¹³ Ω/sq . Pre-annealing plasma treatments were investigated in order to improve the electrical properties while avoiding high temperature treatments. Composite RIE treatment recipes consisting of alternating RIE treatments in O₂ plasma and in Ar plasma were able to reduce the sheet resistance of as spin coated ITO films by 4-5 orders of magnitude, from about 10¹³ Ω/sq in as-coated films to about 3 x 10⁸ Ω/sq without any annealing. Plasma treatment, in combination with annealing treatments were able to decrease the sheet resistance by 8-9 orders of magnitude down to almost 10 kΩ/sq , equivalent to bulk resistivity of ~0.67 Ω.cm. Investigation into effectiveness of various RIE parameters in removing residual organics and in reducing the sheet resistance of colloidal ITO films suggested that while reactive ion annealing (RIE) pressure is an important parameter; parameters like plasma power, number of alternating O₂-Ar RIE cycles were also effective in reducing the residual organic content. Impedance spectroscopy analysis of the colloidal ITO films indicated the dominance of the various interfaces, such as grain boundaries, insulating secondary phases, charge traps, and others in determining the observed electrical properties.
12
Che, Hui. "Surface Chemistry and Work Function of Irradiated and Nanoscale Thin Films Covered Indium Tin Oxides." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157651/.
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In this study, we used UV-ozone Ar sputtering, X-ray photoelectron and ultra-violet photoelectron spectroscopies and sputtering based depositions of RuO2 and Se nano-layers on indium tin oxides (ITOs). We elucidated the effect of Ar sputtering on the composition and chemistry of Sn rich ITO surface. We demonstrated that while a combination of UV-ozone radiation and Ar sputtering removes most of the hydrocarbons responsible for degrading the work function of ITO, it also removes significant amount of the segregated SN at the ITO surface that's responsible for its reasonable work function of 4.7eV. We also demonstrated for the first time that sputtering cleaning ITO surface leads to the reduction of the charge state of Sn from Sn4+ to Sn2+ that adds to the degradation of the work function. For the nano-layers coverage of ITO studies, we evaluated both RuO2 and Se. For RuO2 coated ITO, XPS showed the formation of a Ru-Sn-O ternary oxide. The RuO2 nano-layer reduced the oxidation state of Sn in the Sn-rich surface of ITO from +4 to +2. The best work function obtained for this system is 4.98eV, raising the effective work function of ITO by more than 0.5 eV. For the Se coated ITO studies, a systematic study of the dependence of the effective work function on the thickness of Se overage and its chemistry at the Se/ITO interface was undertaken. XPS showed that Se reacts with Sn at the Sn-rich surface of ITO determined the presence of both negative and positive oxidation state of Se at the Se/ITO interface. The Se also reduced the oxidation state of Sn from Sn4+ to Sn2+ in the Sn-rich ITO surface. The highest effective work function obtained for this system is 5.06eV. A combination of RuO2/Se nanoscale coating of optimally cleaned ITO would be a good alternative for device applications that would provide work function tuning in addition to their potential ability to act as interface stabilizers and a barrier to reaction and inter-diffusion at ITO/active layers interfaces responsible for long term stability of devices and especially organic solar cells and organic light emitting diodes.
13
Gasparetto, Jacopo. "Investigation of indium tin oxide-titanium dioxide interconnection layers for perovskite-silicon tandem solar cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14230/.
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Per superare i limiti di efficienza delle tradizionali celle al silicio, dovuti alla termalizzazione degli elettroni generati dai fotoni solari più energetici, la comunità scientifica si è recentemente indirizzata verso la tecnologia di celle tandem monolitiche perovskite-silicio. In questo tipo di dispositivi, una cella perovskite viene depositata direttamente su di una cella etero-giunzione al silicio (SHJ) ad alta efficienza e, grazie al suo band gap, assorbe i fotoni più energetici permettendo un efficienza totale maggiore. Le celle perovskite attualmente in fase di studio presso Fraunhofer ISE possiedono un contatto posteriore formato da diossido di titanio (TiO2), mentre il contatto frontale delle celle SHJ è formato tipicamente di indium tin oxide (ITO). In questo lavoro si è studiata la fattibilità di celle solari tandem perovskite-silicio, analizzando dettagliatamente l’interfaccia ITO/TiO2 e la sua resistività. Poiché la resistenza di serie di una cella fotovoltaica, di qualunque natura, è un parametro fortemente limitate per l’efficienza di conversione, è necessario che questi layer di interconnessione abbiano una resistenza più bassa possibile per non causare perdite dovute al trasporto dei portatori di carica. Sono stati preparati campioni con formati da uno stack ITO/TiO2/ITO depositato su un substrato di silicio. Tutti i layer di ITO sono stati depositati tramite sputtering mentre sono state testate tre differenti tecniche di deposizione per il TiO2: Electron Beam Physical Vapour Deposition (EBPVD), Thermal Atomic Layer Deposition (T-ALD) e Plasma Enhanced ALD (PE-ALD). Per ogni tecnica di deposizione del TiO2 si è studiata la resistenza dei film, anche in seguito a trattamenti termici a differenti condizioni. Sono state inoltre condotte analisi di diffrazione a raggi X (XRD) e spettroscopia fotoelettronica a raggi X (XPS) per sondare la struttura cristallina e la composizione chimica dei layer di TiO2 depositati su ITO tramite le differenti tecniche.
14
Firmiano, Edney Geraldo da Silveira. "Síntese, caracterização e deposição sobre óxido de grafeno de nanopartículas de óxido de índio dopado com estanho (ITO)." Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/6558.
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Previous issue date: 2011-11-22Universidade Federal de Sao Carlos
In this study, in the first step, Indium tin oxide nanoparticles were synthesized via a non-aqueous route involving the solvothermal treatment of indium (III) acetylacetonate and tin (IV) chloride in polyethylene glycol Mw=1000. The use of microwave heating reduced the reaction time considerably when compared to traditional heating methods. An analysis by transmission electron microscopy (TEM) revealed particles of relatively uniform sizes and shapes. The high crystallinity of the material was observed by high resolution transmission electron microscopy (HRTEM). The nanocristal size founded by count was 5,1nm. A powder X-ray diffraction analysis indicated that all the materials were crystalline. Infrared spectra confirmed the presence of organic material on the nanoparticle surface. By thermogravimetric analysis (TGA) determined that 11.3% of the total mass corresponds to the polymer. Resistivity values below 10-1 Ω.cm were obtained in thin films and pellets, and semiconductor behavior. In the second step, a model to control the covered area of graphene oxide (GO) sheets by ITO nanoparticles was proposed. The method used was add graphene oxide at the synthetic route to obtain pure ITO. The composites were characterized by XRD, FT-IR, TGA and TEM. XRD results for the synthesized materials confirmed the diffraction patterns of ITO in the different composites synthesized. Through the analysis of FT-IR was possible confirm the presence of the polymer formed on the surface of the oxide nanoparticle and functional groups of graphene oxide sheets. The polymer attached on the oxide surface is responsible for the strong interaction between the ITO and graphen oxide sheets. TEM images for the samples with different cover percentage showed the controller achieved with the synthesis proposed. The composite with 100 or 10% of metal oxides covering the sheets surface did not show the presence of nanocrystals out sheets. The percent value of the covered area obtained of 15% founded by image J analisys is near to the calculated value. From this value we can say that the model works well to control the covered area of GO by nanocristals. The electrical resistivity values found are comparable to the pure ITO, however, with a smaller amount of ITO.
Neste estudo, na primeira etapa, nanopartículas de óxido de índio dopado com estanho foram sintetizadas por uma rota não aquosa envolvendo o tratamento solvotermal de acetilacetonato de índio (III) e cloreto de estanho (IV) em polietilenoglicol de massa molecular 1000. O uso de aquecimento auxiliado por microondas reduziu o tempo de reação quando comparado aos métodos tradicionais de aquecimento. A análise por microscopia eletrônica de transmissão (TEM) mostrou partículas com tamanho e forma relativamente uniformes. A alta cristalinidade do material foi observada por microscopia eletrônica de alta resolução (HRTEM). O tamanho dos nanocristais obtidos por contagem foi de 5,1 nm. A análise de difração de Raios-X (DRX) indicou a cristalinidade do material. O espectro de infravermelho (FT-IR) confirmou a presença do material orgânico na superfície das nanopartículas. Pela análise termogravimétrica (TGA) determinou que 11,3% da massa total corresponde ao polímero. Resistividade abaixo de 10-1 Ω.cm foi obtido no filme e na pastilha, com comportamento semicondutor do óxido. Na segunda etapa, um modelo de controlar a área das folhas de óxido de grafeno (OG) coberta por nanocristais foi proposto. O método usado foi adicionar óxido de grafeno à rota de síntese do ITO puro. Os compósitos foram caracterizados por DRX, FT-IR, TGA e TEM. Os resultados de difração de Raios-X confirmaram o padrão de difração do ITO nos diferentes compósitos. Pela análise de FT-IR foi possível confirmar a presença do polímero na superfície das nanoparticulas e os grupos funcionais das folhas de óxido de grafeno. O polímero ligado na superfície do óxido e responsável pela forte interação entre o ITO e as folhas de óxido de grafeno. As imagens de TEM para as amostras com porcentagens de cobertura diferente mostraram o controle alcançado com o método de síntese proposto. Os compósitos com 100% e 10% de óxido metálico cobrindo a superfície das folhas mostraram que não ocorreu a formação de nanopartículas fora das folhas. O valor de 15 % de porcentagem de área coberta obtido é próximo ao valor calculado. A partir deste valor, pode-se dizer que o modelo funciona bem para controlar a área de OG coberta por nanocristais. Os valores de resistividade elétrica encontrados são comparáveis ao ITO puro, no entanto, com uma quantidade menor de ITO.
15
Rajala, Jonathan Watsell. "ELECTROSPINNING FABRICATION OF CERAMIC FIBERS FOR TRANSPARENT CONDUCTING AND HOLLOW TUBE MEMBRANE APPLICATIONS." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1480909959851349.
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Morken, Michael Owen Morken. "An Investigation Into The Feasibility Of Transparent Conductive Coatings At Visimax Technologies." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1496835960043161.
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Berengue, Olivia Maria. "Estudo das propriedades estruturais e de transporte eletrônico em nanoestruturas de óxidos semicondutores e metálicos." Universidade Federal de São Carlos, 2010. https://repositorio.ufscar.br/handle/ufscar/4925.
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Previous issue date: 2010-05-07Universidade Federal de Minas Gerais
The structural and transport features of oxide nanostructures synthesized by a vapour phase aproach: the VLS and VS methods were investigated in this work. ITO and In2O3 nanowires were characterized by using XRD, HRTEM and FEG-SEM techniques. Both nanostructures were found to be body-centered cubic (bixbyite, point group Ia3) single crystals with a well defined growth direction. Raman spectroscopy was used in order to study the nanowires composition, crystalline character and the role of tin atoms in the In2O3 lattice (ITO) was studied as well. The influence of the structural disorder induced by doping was pointed as the main cause of the break of the selection rules in ITO and it was promptly recognized in the Raman spectrum. The metallic character observed in In2O3 micrometric wires was assigned to the electron-phonon scattering in agreement with the Bloch-Grüneisen theory. ITO samples with different sizes were analysed in the framework of the Bloch-Grüneisen theory and at high temperatures (T > 77 K) they were found to present a typical metallic character. It was observed at low temperatures (T < 77 K) and in small samples a negative temperature coefficient of resistance which is an evidence that quantum interference processes are present. A weak localized character was found in these samples as detected in magnetoresistance measurements. The electron s phase break was associated to the electronelectron scattering (T < 77 K) and the electron-phonon scattering (T > 77 K). The transport measurements in one-nanowire based FET provided data on the electron s mobility and density. Tin oxide nanobelts were also studied and their structural and electrical characterizations were obtained. In this case the association of several structural measurements provided that the samples are rutile-like single crystals (point group P42/mnm) grown by the VS mechanism. The transport measurements provided data on the nanobelts gap energy (3.8 eV) and on the transport mechanisms acting in different temperature ranges. An activated-like process and the variable range hopping were found to be present in different temperature range and additionally the localization length was determined. The influence of additional levels inside the gap caused by oxygen vacancies was studied by performing light and atmosphere-dependent experiments and as a result a photo-activated character was detected. Thermally stimulated current measurements provided evidence that only one level associated to the oxygen vacancies at 1.8 eV seems to contribute to the transport in SnO2 nanobelts. Triclinic single crystalline nanobelts were identified as the Sn3O4 phase and were analyzed by transport measurements. The samples were wide band gap semiconductors and the role of oxygen vacancies was identified by using PL and PC measurements. The semiconductor behavior was confirmed by the electron transport data, which pointed to the variable range hopping process as the main conduction mechanism (55 K < T < 398 K) and data on localization length and on the hopping distance were obtained. The presence of additional levels due to oxygen vacancies and tin interstitials was recognized in the samples by performing photo-activated and thermally stimulated current measurements.
Neste trabalho foram investigadas características estruturais e de transporte eletrônico em nanoestruturas óxidas sintetizadas por métodos baseados em fase de vapor: os métodos VLS e VS. Amostras de In2O3 e ITO foram caracterizadas quanto às suas características estruturais usando-se técnicas experimentais como XRD, HRTEM e FEG-SEM e comprovou-se que são monocristais cúbicos de corpo centrado (bixbyite) pertencentes ao grupo puntual Ia3 com direção preferencial de crescimento bem definida. A espectroscopia Raman foi utilizada como ferramenta fundamental para o estudo da composição destes materiais, confirmando a fase, o caráter monocristalino bem como a presença de dopantes na estrutura do In2O3 como no caso do ITO. Estudou-se ainda a influência da desordem estrutural causada pela dopagem nas estruturas já que esta se reflete diretamente em uma quebra na regra de seleção do material e portanto, no espectro Raman. O estudo dos mecanismos de transporte eletrônico em microfios de In2O3 mostrou uma característica essencialmente metálica nestes materiais, comprovada pela identificação do espalhamento elétron-fônon (teoria de Bloch-Grüneisen) como a principal fonte de espalhamento. Amostras de ITO com diferentes tamanhos também foram estudadas e observou-se, acima de 77 K, o aumento da resistência com o aumento da temperatura também caracterizado pela interação elétron-fônon. A observação de um coeficiente negativo de temperatura da resistência observado na amostra nanométrica e em baixas temperaturas aponta para a presença de processos quânticos de interferência originados principalmente da redução da dimensionalidade da amostra. De fato, a aplicação de um campo magnético mostrou a supressão desse comportamento em função da temperatura, comprovando assim que a chamada localização fraca encontra-se presente no nanofio de ITO. Nesse caso, a destruição da fase do elétron foi associada ao espalhamento elétron-elétron (T < 77 K) e ao espalhamento elétron-fônon (T > 77 K). O uso das referidas amostras como transistores de efeito de campo permitiu ainda a obtenção de parâmetros importantes como a mobilidade e a densidade de portadores nas amostras. Nanofitas de SnO2 também foram estudadas e suas propriedades estruturais e de transporte eletrônico foram obtidas. Nesse caso encontrou-se através de técnicas de medida variadas que as amostras são monocristais com estrutura do tipo rutila (grupo puntual P42/mnm) sintetizadas pelo método VS. Diferentes experimentos de transporte eletrônico permitiram a determinação do gap de energia deste material em 3.8 eV e ainda permitiram identificar a presença de diferentes mecanismos de transporte atuando em intervalos de temperatura bem determinados. De fato observou-se a transição de um comportamento de ativação térmica para um comportamento localizado e também ativado por fônons, o hopping donde se determinou o comprimento de localização eletrônico. A presença de níveis adicionais ao gap de energia foi estudada através de experimentos feitos em diferentes atmosferas e sob ação de luz ultravioleta visando explorar o caráter foto-ativado detectado nas amostras. Foi observado de medidas termicamente estimuladas a emissão termiônica de portadores através dos contatos elétricos o que indica que o único nível que parece contribuir com portadores livres nas nanofitas de SnO2 é aquele detectado em 1.8 eV. Amostras monocristalinas com estrutura triclínica, com morfologia de fita e cuja fase foi identificada como sendo Sn3O4 foram também investigadas. A presença de vacâncias de oxigênio e de um gap largo de energia foram observadas através de experimentos de PL e PC. O hopping foi identificado em um grande intervalo de temperaturas (55 K < T < 398 K) como o principal mecanismo de transporte eletrônico observado nas amostras o que comprova a presença de localização e também indica que as amostras se comportam como um semicondutor. Adicionalmente, parâmetros como o comprimento de localização e a distância de pulo dos elétrons foram calculadas. A presença de vacâncias de oxigênio nestas amostras foi ainda estudada através de medidas foto-ativadas pela luz ultravioleta e em diferentes atmosferas de medida, e também por experimentos de TSC donde obteve-se evidências adicionais sobre a presença de outras fontes de elétrons livres como vacâncias superficiais ou interstícios de estanho, contribuindo para o transporte nestas amostras.
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Giordano, Anthony J. "Altering the work function of surfaces: The influential role of surface modifiers for tuning properties of metals and transparent conducting oxides." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53989.
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This thesis focuses on the use of surface modifiers to tune the properties of both metals and metal oxides. Particular attention is given to examine the modification of transparent conducting oxides (TCOs) including indium tin oxide and zinc oxide both through the use of phosphonic acids as well as organic and metal-organic dopants. In this thesis a variety of known and new phosphonic acids are synthesized. A subset of these molecules are then used to probe the relationship between the ability of a phosphonic acid to tune the work function of ITO and how that interrelates with the coverage and molecular orientation of the modifier on the surface. Experimental techniques including XPS, UPS, and NEXAFS are coupled with theoretical DFT calculations in order to more closely examine this relationship.
Literature surrounding the modification of zinc oxide with phosphonic acids is not as prevalent as that found for the modification of ITO. Thus, effort is placed on attempting to determine optimal modification conditions for phosphonic acids on zinc oxide. As zinc oxide is already a low work function metal oxide, modifiers were synthesized in an attempt to further decrease the work function of this substrate in an effort to minimize the barrier to carrier collection/injection. Etching of the substrate by phosphonic acids is also examined.
In a related technique, n- and p-dopants are used to modify the surfaces of ITO, zinc oxide, and gold and it was found that the work function can be drastically altered, to approximately 3.3 – 3.6 eV for all three of the substrates examined. Surface reactions are straightforward to conduct typically taking only 60 s to achieve this change in work function.
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Fung, Man-kin, and 馮文健. "Fabrications of tin-doped indium oxide nanostructures and their applications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47849459.
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Tin-doped indium oxide (ITO) has been widely used for various optoelectronic devices such as display panels, light-emitting diodes and solar cells due to its unique optical and electrical properties. Thin ITO films can be fabricated by a number of methods such as molecular beam epitaxy (MBE), laser ablation, dc sputtering, e-beam deposition, vapor phase deposition, electrochemical deposition and hydrothermal method. Apart from the conventional thin film form, one dimensional ITO nanorods or nanowires are attracting much research interest due to their high aspect ratio and large surface to volume ratio. For instance, a network made of ITO nanowires can exhibit high transparency (over 95 %) and high flexibility without losing its conducting property as reported recently. This network can be potentially used for flexible photovoltaic devices.
In this study, ITO nanorods or nanowires were fabricated using the vapor deposition, dc sputtering and e-beam deposition. The use of short ITO nanorods (100 nm) on glass and commercial ITO substrates as bottom electrodes improving the charge collection of bulk heterojunction organic solar cells had been demonstrated. The morphology of the ITO nanostructures was studied by scanning electron microscope (SEM) and transmission electron microscope (TEM). The crystal structure and growth direction were studied by x-ray diffraction (XRD) and selected area electron diffraction (SAED), respectively. Optical properties were examined using transmission and photoluminescence measurements. The performance of the organic solar cells was examined using the I-V characteristics and external quantum efficiency (EQE) measurements.
The growth mechanism of the ITO nanowires using different fabrication methods was discussed. The effects of the substrate temperature, oxygen content, choice of substrate and evaporation rate on the morphology, transmittance and sheet resistivity were investigated. When short ITO nanorods were incorporated into the bulk heterojunction organic solar cells, a significant improvement of the power conversion efficiency (PCE) was observed. The higher efficiency of the studied solar cells was attributed to the improved charge collection.published_or_final_version
Physics
Doctoral
Doctor of Philosophy
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Havard, Eric. "Contribution à l'étude de l'injection électrique dans les VCSEL de grandes dimensions." Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00353238.
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Ce travail de thèse porte sur la modélisation, la fabrication et la caractérisation de Lasers à Cavité Verticale Emettant par la Surface (VCSEL) de grandes dimensions pour la manipulation de solitons de cavité, pour lesquels ces lasers permettraient une manipulation électrique plus souple de ces ondes stationnaires. Pour cela, il est nécessaire de disposer de structures à large zone d'émission uniforme (~100µm). Or, l'injection par électrode annulaire dans les VCSEL émettant par la surface entraîne une inhomogénéité rédhibitoire. Cette étude vise donc à proposer et évaluer des solutions technologiques innovantes pour atteindre une uniformité optimale dans ces dispositifs. Après une introduction dressant un état de l'art des solutions rapportées dans la littérature, nous présentons les travaux que nous avons menés sur la modélisation électrique des lasers pour évaluer les approches génériques de complexité croissante suivantes : l'ajout d'une couche d'étalement du courant en surface (électrode transparente en ITO) ; l'association de cette dernière à une barrière de potentiel (diode Zener) et la discrétisation de l'injection par création de zones localisées de conduction. L'optimisation des électrodes en ITO déposées sur GaAs, l'évaluation de l'apport d'une diode Zener ainsi que la mesure du contraste d'injection obtenu par gravure localisée en surface du composant sont ensuite détaillées. Suite à cette mise au point technologique, l'insertion des solutions que nous avons finalement retenues (gravures localisées et ITO) pour la réalisation de VCSEL est ensuite décrite. Enfin, les caractérisations électro-optiques des composants réalisés sont présentées; elles ont déjà permis d'obtenir des dispositifs de forme allongée émettant 50mW en continu à l'ambiante. Ces premiers résultats prometteurs ont cependant mis en évidence la nécessité d'améliorer encore les propriétés de l'interface ITO/GaAs. Ces solutions pourront alors être mises à profit pour l'application visée mai s également pour la génération de puissance ou encore la réalisation de VCSEL à cavité externe (VECSEL).
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Kovařík, Martin. "Charakterizace elektronických vlastností nanodrátů pro elektrochemii." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402570.
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Elektrochemické metody nacházejí využití v mnoha aplikacích (např. senzorice, skladování el. energie nebo katalýze). Jejich nespornou výhodou je nízká finanční náročnost na přístrojové vybavení. Abychom lépe porozuměli procesům probíhajícím na elektrodách, je dobré znát elektronickou pásovou strukturu materiálu elektrody. Úkolem této práce je vyhodnotit výstupní práci a pozici hrany valenčního pásu nových materiálů pro elektrody, konkrétně cínem dopovaného oxidu india pokrytého nanotrubicemi sulfidu wolframičitého. Ultrafialová fotoelektronová spektroskopie a Kelvinova silová mikroskopie jsou metody použité pro tuto analýzu. Zvláštní důraz je kladen na přípravu vzorků elektrod pro měření, aby nedošlo k nesprávné interpretaci výsledků vlivem vnějších efektů jako je např. kontaminace nebo modifikace povrchu.
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Lounis, Sebastien Dahmane. "The influence of dopant distribution on the optoelectronic properties of tin-doped indium oxide nanocrystals and nanocrystal films." Thesis, University of California, Berkeley, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3686398.
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Colloidally prepared nanocrystals of transparent conducting oxide (TCO) semiconductors have emerged in the past decade as an exciting new class of plasmonic materials. In recent years, there has been tremendous progress in developing synthetic methods for the growth of these nanocrystals, basic characterization of their properties, and their successful integration into optoelectronic and electrochemical devices. However, many fundamental questions remain about the physics of localized surface plasmon resonance (LSPR) in these materials, and how their optoelectronic properties derive from their underlying structural properties. In particular, the influence of the concentration and distribution of dopant ions and compensating defects on the optoelectronic properties of TCO nanocrystals has seen little investigation.
Indium tin oxide (ITO) is the most widely studied and commercially deployed TCO. Herein we investigate the role of the distribution of tin dopants on the optoelectronic properties of colloidally prepared ITO nanocrystals. Owing to a high free electron density, ITO nanocrystals display strong LSPR absorption in the near infrared. Depending on the particular organic ligands used, they are soluble in various solvents and can readily be integrated into densely packed nanocrystal films with high conductivities. Using a combination of spectroscopic techniques, modeling and simulation of the optical properties of the nanocrystals using the Drude model, and transport measurements, it is demonstrated herein that the radial distribution of tin dopants has a strong effect on the optoelectronic properties of ITO nanocrystals.
ITO nanocrystals were synthesized in both surface-segregated and uniformly distributed dopant profiles. Temperature dependent measurements of optical absorbance were first combined with Drude modeling to extract the internal electrical properties of the ITO nanocrystals, demonstrating that they are well-behaved degenerately doped semiconductors displaying finite conductivity at low temperature and room temperature conductivity reduced by one order of magnitude from that of high-quality thin film ITO.
Synchrotron based x-ray photoelectron spectroscopy (XPS) was then employed to perform detailed depth profiling of the elemental composition of ITO nanocrystals, confirming the degree of dopant surface-segregation. Based on free carrier concentrations extracted from Drude fitting of LSPR absorbance, an inverse correlation was found between surface segregation of tin and overall dopant activation. Furthermore, radial distribution of dopants was found to significantly affect the lineshape and quality factor of the LSPR absorbance. ITO nanocrystals with highly surface segregated dopants displayed symmetric LSPRs with high quality factors, while uniformly doped ITO nanocrystals displayed asymmetric LSPRs with reduced quality factors. These effects are attributed to damping of the plasmon by Coulombic scattering off ionized dopant impurities.
Finally, the distribution of dopants is also found to influence the conductivity of ITO nanocrystal films. Films made from nanocrystals with a high degree of surface segregation demonstrated one order of magnitude higher conductivity than those based on uniformly doped crystals. However, no evidence was found for differences in the surface electronic structure from one type of crystal to the other based on XPS and the exact mechanism for this difference is still not understood.
Several future studies to further illuminate the influence of dopant distribution on ITO nanocrystals are suggested. Using synchrotron radiation, detailed photoelectron spectroscopy on clean ITO nanocrystal surfaces, single-nanoparticle optical measurements, and hard x-ray structural studies will all be instructive in elucidating the interaction between oscillating free electrons and defect scattering centers when a plasmon is excited. In addition, measurements of temperature and surface treatment-dependent conductivity with carefully controlled atmosphere and surface chemistry will be needed in order to better understand the transport properties of ITO nanocrystal films. Each of these studies will enable better fundamental knowledge of the plasmonic properties of nanostructures and improve the development of nanocrystal based plasmonic devices.
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Peng, Chunqing. "Electrostatic layer-by-layer assembly of hybrid thin films using polyelectrolytes and inorganic nanoparticles." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43684.
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Polymer/inorganic nanoparticle hybrid thin films, primarily composed of functional inorganic nanoparticles, are of great interest to researchers because of their interesting electronic, photonic, and optical properties. In the past two decades, layer-by-layer (LbL) assembly has become one of the most powerful techniques to fabricate such hybrid thin films. This method offers an easy, inexpensive, versatile, and robust fabrication technique for multilayer formation, with precisely controllable nanostructure and tunable properties. In this thesis, various ways to control the structure of hybrid thin films, primarily composed of polyelectrolytes and indium tin oxide (ITO), are the main topics of study. ITO is one of the most widely used conductive transparent oxides (TCOs) for applications such as flat panel displays, photovoltaic cells, and functional windows. In this work, polyethyleneimine (PEI) was used to stabilize the ITO suspensions and improve the film buildup rate during the LbL assembly of poly(sodium 4-styrenesulfonate) (PSS) and ITO. The growth rate was doubled due to the stronger interaction forces between the PSS and PEI-modified ITO layer. The assembly of hybrid films was often initiated by a polyelectrolyte precursor layer, and the characteristics of the precursor layer were found to significantly affect the assembly of the hybrid thin films. The LbL assembly of ITO nanoparticles was realized on several substrates, including cellulose fibers, write-on transparencies, silicon wafers, quartz crystals, and glasses. By coating the cellulose fibers with ITO nanoparticles, a new type of conductive paper was manufactured. By LbL assembly of ITO on write-on transparencies, transparent conductive thin films with conductivity of 10⁻⁴ S/cm and transparency of over 80 % in the visible range were also prepared. As a result of this work on the mechanisms and applications of LbL grown films, the understanding of the LbL assembly of polyelectrolytes and inorganic nanoparticles was significantly extended. In addition to working with ITO nanoparticles, this thesis also demonstrated the ability to grow bicomponent [PEI/SiO₂]n thin films. It was further demonstrated that under the right pH conditions, these films can be grown exponentially (e-LbL), resulting in much thicker films, consisting of mostly the inorganic nanoparticles, in much fewer assembly steps than traditional linearly grown films (l-LbL). These results open the door to new research opportunities for achieving structured nanoparticle thin films, whose functionality depends primarily on the properties of the nanoparticles.
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Simmonds, Adam. "INVESTIGATION OF ORGANIC OPTO-ELECTRONIC SEMICONDUCTING DEVICES: ANODE SURFACE ETCHING, APPLICATION INTO NOVEL INTEGRATED STRUCTURES, AND THE ANALYSIS OF PHOTOCURRENT PROPERTIES IN PHOTOVOLTAICS." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194757.
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Indium-tin oxide (ITO) is commonly used as the transparent electrode in organic photovoltaic (OPV) devices. ITO's transparent properties come at the expense of less than ideal electrode characteristics arising from insulating over-oxidized surface species. OPVs fabricated on the native ITO surface tend to exhibit poor performance with a high degree of variability from device to device. Aggressive acid etching of the ITO surface removes the majority of the insulating surface species leading to improvements in OPV efficiency with greater reproducibility and increased device to device consistency.Organic light emitting diodes (OLEDs) are planar electroluminescent light sources that naturally couple a portion of their emission into internally reflected modes within the device substrate. Although this coupling property is well known, few attempts have been made to integrate OLEDs as light sources for internal reflection elements. Furthermore, OPVs share the optical coupling properties of OLEDs and therefore can be used as integrated internal reflection detectors. Integrating both an OLED light source and an OPV detector onto the same substrate results in an internal reflection sensing platform that requires no free-space optics, has low power consumption requirements, and can be easily fabricated on substrates occupying an area less than one square inch. In this work we establish a functional prototype design, characterize the fundamental coupling properties, and demonstrate several surface sensing responses of this fully integrated optical sensing platform.The net solar power production from OPVs arises from the interactions between multiple currents through the device. The photocurrent is the only power producing current in the device and understanding the voltage dependent nature of this current is essential in OPV research. Analysis methods of conventional, inorganic photovoltaics do not adequately describe the photocurrent behavior commonly observed in OPVs. OPV analysis is therefore somewhat limited by the methods commonly employed. To improve upon the convention methods we develop a simplified method of OPV photocurrent analysis based on electrochemical methods that accurately describes the voltage dependence of the photocurrent and leads to greater insight into the key parameters involved in solar power production from OPVs.
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Rusinek, Cory A. "New Avenues in Electrochemical Systems and Analysis." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490350904669695.
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Ramsbrock, Jens. "Fabrication and characterisation of a novel blue organic light-emitting diode (OLED)-structure : glass/Indium-Tin oxide/Poly (N-vinylcarbazole) doped with dye p-Bis(o-methylstyryl)benzeneAluminium." Thesis, Edinburgh Napier University, 2000. http://researchrepository.napier.ac.uk/Output/4166.
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Kotsedi, Lebogang. "Fabrication and characterization of a solar cell using an aluminium p-doped layer in the hot-wire chemical vapour deposition process." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1349_1363785866.
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When the amorphous silicon (a-Si) dangling bonds are bonded to hydrogen the concentration of the dangling bond is decreased. The resulting film is called hydrogenated amorphous silicon (a-Si:H). The reduction in the dangling bonds concentration improves the optoelectrical properties of the film. The improved properties of a-Si:H makes it possible to manufacture electronic devices including a solar cell. A solar cell device based on the hydrogenated amorphous silicon (a-Si:H) was fabricated using the Hot-Wire Chemical Vapour Deposition (HWCVD). When an n-i-p solar cell configuration is grown, the norm is that the p-doped layer is deposited from a mixture of silane (SiH4) gas with diborane (B2H6). The boron atoms from diborane bonds to the silicon atoms and because of the number of the valance electrons, the grown film becomes a p-type film. Aluminium is a group 3B element and has the same valence electrons as boron, hence it will also produce a p-type film when it bonds with silicon. In this study the p-doped layer is grown from the co-deposition of a-Si:H from SiH4 with aluminium evaporation resulting in a crystallized, p-doped thin film. When this thin film is used in the n-i-p cell configuration, the device shows photo-voltaic activity. The intrinsic layer and the n-type layers for the solar cell were grown from SiH4 gas and Phosphine (PH3) gas diluted in SiH4 respectively. The individual layers of the solar cell device were characterized for both their optical and electrical properties. This was done using a variety of experimental techniques. The analyzed results from the characterization techniques showed the films to be of device quality standard. The analysed results of the ptype layer grown from aluminium showed the film to be successfully crystallized and doped. A fully functional solar cell was fabricated from these layers and the cell showed photovoltaic activity.
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Day, Stephen. "Controlling charge carrier injection in organic electroluminescent devices via ITO substrate modification." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368243.
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Peng, Yeh-Chun, and 彭彥鈞. "Electrochemical behavior of transparent conductive Al-doped zinc oxide(AZO) and tin-doped indium oxide(ITO) films." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/40131951394867959955.
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碩士國立中央大學
機械工程研究所
95
The electrochemical behavior of Al-doped zinc oxide(AZO)、Tin-doped indium oxide(ITO)、Sc-doped AZO and AZO annealed at 300℃ for 1hr were immersed in 3.5%NaCl and in different buffer solutions varying with pH were investigated in this work. Electrochemical techniques such as measurement of open circuit potential, linear polarization, cyclic voltammograms, electrochemical impedance spectroscopy were employed. Reaction products on the surface of oxides under different potentials were examined for those produced on a variety of potentials in different duration. The corrosion resistance of difference oxide films to 3.5%NaCl solution decreases in the order: annealed 300℃ AZO＞ITO＞Sc-doped AZO＞AZO. Sc-doped tends to in increase the corrosion resistance of the AZO thin films. The corrosion resistance to 3.5%NaCl for Sc-doped AZO decreases with decreasing the concentration of Sc-doped：0.242wt%＞0.134wt%＞0.006wt%＞0wt%. The electrochemical behavior of AZO and the AZO anneal at 300℃ for 1h in various buffer solutions was studied using cyclic voltammetry under a scan rate of 50mV/s. The reduction current and characteristic oxidation current are lower in the annealed AZO then the usual AZO, this fact reflects that annealed AZO is more resistance to corrosion in buffer solutions.
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Jing-LiYang and 楊景立. "Fabrication of Indium-Tin-Oxide (ITO) Based Chemical Sensors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/64060778794687058417.
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碩士國立成功大學
微電子工程研究所碩博士班
101
In recent years, semiconductor-based gas sensors have become the mainstream in the sensing territory due to its high sensing response, small size, and simple fabrication. Also, the development and application of biosensors have expanded in various fields such as medicine, chemical, and food industry. In this study, gas sensors and glucose biosensors were based on the indium tin oxide (ITO) thin film which is an n-type semiconductor with a superior electrical conductivity and optical transparency. The composition and structure of the thin film could be acquired by a series of atomic force microscope (AFM), x-ray diffraction (XRD), and scanning electron microscope (SEM) measurements. For gas sensing, ITO thin film-based sensors were fabricated by RF sputtering with (a) substrate-preheated temperature, (b) Au-nanodots, and (c) in a combination of substrate-preheated temperature and Au-nanodots treatments. The characteristics of the studied sensors were studied and demonstrated. For glucose sensing, ITO thin film-based pH sensors were used and various immobilizations of enzymes were accomplished by (a) entrapment, (b) cross-linking, and (c) encapsulation methods. The measurements of (i) calibration curves, (ii) influences of the pH value, (iii) buffer capacity, (iv) response time, and (v) operation and storage stability of the studied device were also discussed and demonstrated in this thesis. The possible suggestions for improvement of the sensing response and the stability of the studied devices were also addressed in chapter 5.
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Cheng-WeiLin and 林正偉. "Fabrication of Indium-Tin-Oxide(ITO) Ammonia Gas Sensors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/78294753357032038330.
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Wang, Yen-Chih, and 王彥智. "Transparent conducting coating composed by Indium-tin oxide (ITO) nanostrips." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/12107803875168375198.
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碩士淡江大學
化學工程與材料工程學系碩士班
101
In this study, fabrication of strip-like indium-tin oxide (ITO) precursors from indium-tin hydroxide (ITH) nanocubes is demonstrated. The strip-like precursors were prepared using a co-precipitation method, in which a polyelectrolyte, poly(styrenesulfonic acid) (PSS), was employed both as the structure-directing agent and stabilizer. The effects of PSS and temperature on morphology of the precursors were investigated. Typical trip-like precursors with 60~100 nm wide and 500~800 nm long were prepared by means of precipitation at room temperature and after aging 3 day. Then ITO nanostrips were prepared from the strip-like precursors by post-calcination. Transparent conductive coatings composed of ITO nanostrips and acrylic binder, 3-(trimethoxy silyl)propyl methacrylate (MSMA), were prepared via doctor-blade coating and UV curing. The structure, morphology, phase, optical and electrical properties of the formed particles and coatings were characterized via TEM, SEM, FTIR, XRD, UV-visible, and four point probe..., etc. Increasing the binder content resulted in a denser structure of the coating and higher transmittance in the visible range. A coating with 0.32 kohm/sq sheet resistance and 82.5% average transmittance could be attained when the weight ratio of MSMA/ITO = 0.6.
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Tsai, Tsung-Ying, and 蔡宗穎. "The Exposure Assessment of the Indium-Tin Oxide (ITO) Processes Workers." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/63983668892983002733.
Full textAbstract:
碩士中山醫學大學
職業安全衛生學系碩士班
102
Aim: Indium-Tin-Oxide (ITO) is a sintered mixture of indium- oxide (In2O3) and tin-oxide (SnO2) with percentages of 90% and 10% (wt/wt) , is used as a transparent conductive coating for liquid crystal displays (LCDs). Until May, 2014, ten cases of interstitial pneumonia in Japanese, four cases of pulmonary alveolar proteinosis (PAP) in US, and one case of PAP in Chinese were found among workers exposed to indium. Case reports, epidemiological studies and animal studies all reveal that exposure to the hardly soluble indium compounds causes interstitial pneumonia as well as emphysematous lung damages, which is so-called “Indium Lung”. The purpose of this study was to assess domestic ITO workers exposure and risk in terms of biological monitoring. Methods: 945 workers were recruited from five domestic ITO and LCD manufacturing plants in this study, in which 668 were exposed workers and 277 were control ones. Each employee was asked to fill out a questionnaire for obtaining information about personal characteristics, life style and occupational history. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the serum and urine indium concentrations. The whole blood samples were analyzed oxidative stress and comet assay. The SPSS 18.0 software packages were used for data management and statistical analysis. Results: Overall average serum concentration with standard deviation of indium exposed worker was 1.40±2.43 (μg/L). Significant positive relationships were found between Serum-In and Urine-In levels. The correlation coefficient was 0.596 (p<0.001)。Serum-In and Urine-In levels of the exposure group were significantly higher than those of the control group. We also according on exposure work years were divided into three groups (A: <3 years; B: 3 ~ 5 years; C: >5 years) in this study. Serum-In and Urine-In levels were increased with exposure time. Based on three years follow-up results, the decreasing trends of oxidative stress and serum indium of 62 workers were found. It demonstrated the protection effects of PAPR and application of good management practice. The increasing trends of TMOM depend on the exposure time. Conclusions: Based on our findings, the possible toxic effects of indium-tin oxide should be paid more attention, and maximum health care measures should be taken to protect workers exposed to ITO. Early detection of health outcomes can prevent any further damages from indium-tin oxide exposure. Significant decrease in Serum-In levels were found in workers wearing PAPR for at least 2 years. In spite of the lower ITO dust exposure concentration in the workplace. It can be accumulated in lung due to hardly soluble property. This may lead to chronic adverse health effects. Therefore, appropriate control measures and proper management practice are important for reduceing indium exposure reduction of indium.
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Chiang, Kun-Han, and 江坤翰. "Characteristics of PEDOT:PSS / indium-tin oxide (ITO) nanocomposite conductive films and hydrogels." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/rv97j5.
Full textAbstract:
碩士淡江大學
化學工程與材料工程學系碩士班
106
Indium-tin hydroxide(ITH) nanostips were prepared by co-precipitation at room temperature and converted into indium-tin oxide(ITO) nanostrips after high-temperature calcination. The formed ITO powder was dispersed in an alkaline aqueous solution (pH12), and then mixed with a conductive polymer (PEDOT/PSS) and a modifier ethylene glycol (EG) to form coating pastes. The coating pastes were coated on glass substrates by using the spin coating method, and the resultant coatings were thermal cured. The effects of ITO content, solvent selection, solution volume ratio, modifier content and film-coating method on the sheet resistance and visible light transmittance of the formed coatings were studied. In the optimal case, a coating with sheet resistance of 108 Ω/sq and average visible transmittance of 87.8% could be prepared. Because ITO can absorb UV light, the transparent conductive coatings with different ITO contents were tested to see their UV resistibility. Conductive polymer PEDOT is known to be electrochromic. Coatings made with different formulations on different substrates were electrochemically tested to see whether the coatings possess electrochromic effect. During preparation of the coating solutions, it was found that ITO can form cross-links with PSS, to induce gelation of the solution. The rheological properties were the gels were tested.
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Hu, Shun-Hao, and 胡舜皓. "Fabrication and Sensing Characteristics of Resistance-Type Indium-Tin-Oxide (ITO) Ammonia Gas Sensors." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/98444971336255036257.
Full textAbstract:
碩士朝陽科技大學
資訊工程系
102
Recently, many different types of gas sensors have been developed and studied. Semiconductor sensors with the advantages of low cost, small size and high sensitivity sensing are widely used. We have successfully fabricated resistive ammonia gas sensors on ITO thin film with differential treatments. The SEM images, AFM images and XRD images were used to analyze the surface morphology of the studied devices. The literature indicates that the surface morphology is similar to the nanorods for ammonia gas sensor fabricated on indium tin oxide (ITO) after the temperature-humidity treatment. This will caused the enhancement of surface-to-volume ratio under more grain boundaries. Based on this concept, the studied devices were treated with temperature-humidity. In this study, the ammonia gas sensors based on ITO thin film with or without underlying Au-naodot have been investigated. From the experimental results, the ammonia gas sensors based on ITO thin film underlying Au-naodot layer can improve its ammonia detecting capability. The ammonia detecting capability can reach to 20ppb NH3 at 150℃. In order to further understand the ammonia sensing characteristics, the transient response data of an ITO-based ammonia sensor are used to analyze. The first-order differential concept was used to analyze the situation of interface vacancy. In the practical application of sensing transmission, how to remove redundant data is a very important issue. In this study, the first differential algorithm was developed to remove over 95% redundancy of the sensing data. Our studied algorithm can reach the goal of reduce the transmission data.
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Lin, Han-chiang, and 林漢強. "Development of Transparent Indium Tin Oxide (ITO)-based Heater Platform for Perfusion Cell Culture." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/94275395287233894461.
Full textAbstract:
碩士義守大學
機械與自動化工程學系碩士班
97
This study reports a transparent indium tin oxide (ITO)-based microheater chip. The attempt of the proposed microheater is to take the role of conventional bulky incubator for cell culture in order to improve integratability with the experimental setup for continuous/perfusion cell culture particularly at micro-scale, to facilitate microscopic observation or other online monitoring activities during cell culture, or even to provide portability of cell culture practice. Different from other ITO-based heating systems, the electrodes of proposed device can be fabricated in a simpler and low cost manner using screen printing technology. Meanwhile, two type ITO-based microheater of single- and double-size have been experimentally fabricated. The experimental evaluation have been conducted to justify that the two-type presented device is capable of providing a spatially uniform thermal environment and precise temperature control with a mild variation of ± 0.2 oC, which is suitable for a general cell culture practice. Finally, to testify that the thermal environment generated by the presented device is well compatible with conventional cell culture-use incubator, chondrocyte perfusion culture was carried out. Results demonstrated that the physiology of the cultured chondrocytes on the developed ITO microheater chip was consistent with that of conventional incubator. All these not only demonstrate the feasibility of using the presented ITO microheater for cell culture purpose but also reveal its potential for other applications in which excellent thermal control is required.
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李智淵. "Properties of pulse magnetron sputter for indium tin oxide (ITO) on polyethesulfone(PES) plastic substrate." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/96242277982289676973.
Full textAbstract:
碩士國立彰化師範大學
機電工程學系
94
his study is to investigate the effect of processes parameter for ITO (Indium Tin Oxide ) deposition on the PES plastic substrate by PMS(Pulse Magnetron Sputter). The process parameter include power, work pressure, pulse frequency, and reverse time. The crystalline of film is analyzed by X-ray diffractiometer. The surface state of films is analyzed with FE-SEM and AFM. The resistivity and transmittance of films are measured by hall measurement system and spectrophotometer. The change of curvature is measured by SEM. The magnitude of film stress was determined by using stoney’s formula. The experiment’s resulted is that the temperature of PMS is lower about Celsius 3-4 degree and higher deposition rate in comparing the sputter of PMS and RF deposition process. In the conductivity of ITO thin film, the input power 60W of PMS has lower value of conductor than RF process. Therefore the PMS is helpful to has good crystalline and electrical properties in low power and low temperature. And this investigate to discover that PMS process can change the duty cycle to improve the surface roughness of ITO by modifying the parameters of pulse frequency and pulse reverse time in deposition ITO thin film. As the pressure, power, duty cycle and deposition time increases that the stress of thin film will increase and make plastic bending. The film produces to break when film increases thickness 1.5nm. In this study working pressure (5×10-3torr), power (60W), pulse frequency (30kHz), reverse time (2μs) and duty cycle(95%) deposit ITO thin film on the plastic. The better results of 3.0×10-4Ω-cm resistivity, 0.85nm RMS surface roughness and 90% transmittance are found in this study. So the PMS’s deposition ITO thin films on the plastic obtain good film quality in lower temperature.
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Liao, Guan-Hung, and 廖冠弘. "Study of Resistance-Type Indium-Tin-Oxide(ITO) Hydrogen Sensing Devices and Related Sensing Circuits." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/00084096727652214108.
Full textAbstract:
碩士朝陽科技大學
資訊工程系
102
We have successfully fabricated an indium tin oxide (ITO)-based resistive sensing device and a hydrogen sensing circuit based on Arduino system. In terms of hydrogen sensors based on semiconductor oxide, ITO-based hydrogen sensor underlying Au-nanodot layer with or without temperature-humidity treatment at differential work temperature and upon differential hydrogen concentration were fabricated and studied. The ITO based hydrogen sensor with temperature treatment has a rougher surface morphology as compared with the ITO based without temperature-humidity treatment one. After the temperature-humidity treatment, the nanorod-like surface morphology will appear. The experimental results indicate that the studied hydrogen sensor with temperature-humidity treatment exhibits higher hydrogen sensitivity at low work temperature regime (<150℃) and higher hydrogen detecting capability at lower hydrogen concentration regime (<100ppm H2/air). This is mainly attributed to the larger specific surface area from the rougher surface. On the other hand, the studied device without temperature-humidity exhibits higher sensitivity at higher temperature and higher hydrogen concentration. This can be attributed that the studied device B has a small resistance; therefore, the resistance allows a greater amount of variation under introducing hydrogen gas. In this study, we also developed a simple hydrogen detecting system based on Arduino developer edition. The hydrogen detection system combined with LCD display and LED to make it easier for users to see if the presence of hydrogen concentration in air exceeds the threshold values.
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Saleh, Mohamed A. "Electro-Mechanical Coupling of Indium Tin Oxide Coated Polyethylene Terephthalate ITO/PET for Flexible Solar Cells." Thesis, 2013. http://hdl.handle.net/10754/292305.
Full textAbstract:
Indium tin oxide (ITO) is the most widely used transparent electrode in flexible solar cells because of its high transparency and conductivity. But still, cracking of ITO on PET substrates due to tensile loading is not fully understood and it affects the functionality of the solar cell tremendously as ITO loses its conductivity. Here, we investigate the cracking evolution in ITO/PET exposed to two categories of tests. Monotonous tensile testing is done in order to trace the crack propagation in ITO coating as well as determining a loading range to focus on during our study. Five cycles test is also conducted to check the crack closure effect on the resistance variation of ITO. Analytical model for the damage in ITO layer is implemented using the homogenization concept as in laminated composites for transverse cracking. The homogenization technique is done twice on COMSOL to determine the mechanical and electrical degradation of ITO due to applied loading. Finally, this damage evolution is used for a simulation to predict the degradation of ITO as function in the applied load and correlate this degradation with the resistance variation. Experimental results showed that during unloading, crack closure results in recovery of conductivity and decrease in the overall resistance of the cracked ITO. Also, statistics about the crack spacing showed that the cracking pattern is not perfectly periodical however it has a positively skewed distribution. The higher the applied load, the less the discrepancy in the crack spacing data. It was found that the cracking mechanism of ITO starts with transverse cracking with local delamination at the crack tip unlike the mechanism proposed in the literature of having only cracking pattern without any local delamination. This is the actual mechanism that leads to the high increase in ITO resistance. The analytical code simulates the damage evolution in the ITO layer as function in the applied strain. This will be extended further to correlate the damage to the resistance variation in following studies.
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She, Li-Wel, and 佘立維. "Absorption property optical property of indium-tin-oxide (ITO) films deposited by glancing-angle sputter system." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60492005360499831761.
Full text
41
"Study of indium tin oxide (ITO) thin films prepared by pulsed DC facing-target Sputtering (FTS)." 2000. http://library.cuhk.edu.hk/record=b5890427.
Full textAbstract:
by Fung Chi Keung = 採用脈衝直流電源對靶濺射技術製備銦錫氧化物薄膜的硏究 / 馮志強.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Fung Chi Keung = Cai yong mai chong zhi liu dian yuan dui ba jian she ji shu zhi bei yin xi yang hua wu bo mo de yan jiu / Feng Zhiqiang.
Acknowledgements --- p.i
Abstract --- p.ii
論文摘要 --- p.iii
Table of contents --- p.iv
List of figures --- p.viii
List of tables --- p.xii
Chapter Chapter 1 --- Introduction --- p.1-1
Chapter 1.1 --- Genesis --- p.1-1
Chapter 1.2 --- Aims and Objectives --- p.1-1
Chapter 1.3 --- Layout of Thesis --- p.1-3
References --- p.1-4
Chapter Chapter 2 --- Literature Review --- p.2-1
Chapter 2.1 --- Introduction to transparent conducting oxides (TCOs) --- p.2-1
Chapter 2.2 --- Indium tin oxide (ITO) --- p.2-2
Chapter 2.2.1 --- Use of ITO --- p.2-2
Chapter 2.2.2 --- Structure and properties of ITO --- p.2-3
Chapter 2.3 --- Properties of ITO films deposited by different growth techniques --- p.2-8
Chapter 2.3.1 --- Sputtering --- p.2-9
Chapter 2.3.2 --- Vacuum evaporation --- p.2-11
Chapter 2.3.3 --- Spray pyrolysis --- p.2-11
Chapter 2.3.4 --- Chemical vapor deposition (CVD) --- p.2-12
Chapter 2.3.5 --- Reactive ion plating --- p.2-12
Chapter 2.4 --- Contradictions in existing literature --- p.2-13
References --- p.2-15
Chapter Chapter 3 --- Thin Film Fabrication and Process --- p.3-1
Chapter 3.1 --- Facing-target sputtering (FTS) --- p.3-1
Chapter 3.2 --- Asymmetric bipolar pulsed DC power source --- p.3-3
Chapter 3.2.1 --- Target poisoning --- p.3-3
Chapter 3.2.2 --- Preferential sputtering --- p.3-4
Chapter 3.2.3 --- Discussion --- p.3-4
Chapter 3.3 --- Substrates --- p.3-6
Chapter 3.3.1 --- Microscopic glass --- p.3-7
Chapter 3.3.2 --- Corning 7059 glass --- p.3-8
Chapter 3.3.3 --- Epitaxial growth --- p.3-8
Chapter 3.3.3.1 --- Epitaxial lattice matching --- p.3-8
Chapter 3.3.3.2 --- Yttrium stabilized zirconia (YSZ) --- p.3-9
Chapter 3.3.3.3 --- Sapphire --- p.3-9
Chapter 3.3.3.4 --- Silicon wafer --- p.3-11
Chapter 3.3.4 --- Substrate cleaning --- p.3-11
Chapter 3.4 --- Targets for the reactive sputtering of ITO films --- p.3-13
Chapter 3.4.1 --- Indium Tin Oxide target (90wt% ln203 : 10wt% Sn04) --- p.3-14
Chapter 3.4.2 --- Indium Tin alloy target (90wt% In : 10wt% Sn) --- p.3-14
Chapter 3.5 --- Deposition conditions --- p.3-16
Chapter 3.5.1 --- Sputter atmosphere --- p.3-16
Chapter 3.5.2 --- Deposition pressure --- p.3-16
Chapter 3.5.3 --- Deposition power --- p.3-17
Chapter 3.5.4 --- Target to substrate distance --- p.3-17
Chapter 3.5.5 --- Pulse frequency and pulse width --- p.3-17
Chapter 3.6 --- Deposition --- p.3-17
References --- p.3-19
Chapter Chapter 4 --- Measurement and Analysis Techniques --- p.4-1
Chapter 4.1 --- Resistivity measurement --- p.4-1
Chapter 4.2 --- "Transmittance, reflectivity and absorption measurements" --- p.4-3
Chapter 4.3 --- Thickness measurement --- p.4-4
Chapter 4.4 --- "Crystal structure, surface morphology and roughness measurements" --- p.4-4
Chapter 4.5 --- Photolithography --- p.4-7
Chapter 4.6 --- Hall effect measurements --- p.4-8
References --- p.4-10
Chapter Chapter 5 --- Experimental results and discussions --- p.5-1
Chapter 5.1 --- Effect of O2 partial pressure --- p.5-1
Chapter 5.1.1 --- Deposition rate --- p.5-2
Chapter 5.1.2 --- Electrical and optical properties --- p.5-4
Chapter 5.1.3 --- Structure and orientation --- p.5-16
Chapter 5.1.4 --- Surface morphology and roughness --- p.5-22
Chapter 5.1.5 --- Conclusion --- p.5-29
Chapter 5.2 --- Effect of substrate temperature --- p.5-29
Chapter 5.2.1 --- Electrical and optical properties --- p.5-29
Chapter 5.2.2 --- Structure and orientation --- p.5-44
Chapter 5.2.3 --- Surface morphology and roughness --- p.5-49
Chapter 5.2.4 --- Conclusion --- p.5-54
Chapter 5.3 --- Effect of vacuum annealing --- p.5-54
Chapter 5.3.1 --- Electrical and optical properties --- p.5-54
Chapter 5.3.2 --- Conclusion --- p.5-59
Chapter 5.4 --- Effect of different substrates --- p.5-59
Chapter 5.4.1 --- Comparison of heteroepitaxial and polycrystalline ITO films --- p.5-60
Chapter 5.4.2 --- Conclusion --- p.5-63
Chapter 5.5 --- Effect of film thickness --- p.5-64
Chapter 5.5.1 --- Film thickness calibration --- p.5-64
Chapter 5.5.2 --- Electrical properties --- p.5-64
Chapter 5.5.3 --- Conclusion --- p.5-67
Chapter 5.6 --- Effect of deposition pressure --- p.5-68
Chapter 5.6.1 --- Deposition rate --- p.5-68
Chapter 5.6.2 --- Electrical properties --- p.5-70
Chapter 5.6.3 --- Conclusion --- p.5-70
Chapter 5.7 --- Effect of target pre-conditioning --- p.5-72
Chapter 5.8 --- Conclusion --- p.5-72
References --- p.5-74
Chapter Chapter 6 --- Further works --- p.6-1
Appendix I
42
Chen, Kuo-Hsing, and 陳國興. "Low-heating-rate Anneal in Improving Electrical and Optical Properties of In-line Sputtered Indium Tin Oxide / Aluminium Zinc Oxide (ITO/AZO)." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39500432962344826221.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
103
Bilayered indium tin oxide and aluminum doped zinc oxide films were prepared by in-line sputtering. Followed by low-heating-rate annealing in vacuum, electric and optic properties of post annealed ITO/AZO films were measured and and compared. Results indicate vacuum annealing provides posittive effects on electrical, optic and microstructure properties of ITO/AZO films. With low-heating-rate annealing process films were vacuum heat treatment. Annealing temperature increase understanding of its manufacturing process so that the film has more reaction time can be lattice repair and rearrange. It makes thin-film crystal for complete. It can also be seen from the SEM image into this phenomenon. With annealing temperature increases, the grain has significant change phenomenon. Keyword：Low-heating-rate Anneal、Indium Tin Oxide、Aluminium Zinc Oxide
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Tong, Jia Zen, and 董佳仁. "Effect of Interfacial Oxygen on Adhesion Strength Between Al/Cr and Indium-Tin-Oxide(ITO) Thin Film Coated Glass." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/24581200417342159594.
Full textAbstract:
碩士義守大學
材料科學與工程學系
89
Metallization of oxide surfaces using aluminum（Al）or gold（Au）is a key process in the fabrication or packaging of electronic and optoelectronic devices. Since these metal thin films provide the electrical and mechanical connection, the adhesion between metal thin films and oxide layer is one of the main concerns in the processing. Higher adhesion strength of metal thin film to oxide surface normally leads to high mechanical reliability of devices. Al thin film with Cr interlayer has been used as a composite layer to metallize ITO-coated glass. The top Al layer provides bondability and electrical conductivity, while the Cr layer is inserted to provide adhesion strength . From a previous study, it is well known that the adhesion between Al/Cr and ITO glass needs to be increased in order to sustain some thermal and mechanical tests. In order to enhance the adhesion between the Al/Cr and ITO glass, oxygen interface doping at the Cr - ITO interface has been proposed in this study. Various deposition parameters（bias, oxygen flow rate）have been used to determine the optimal condition for thin film deposition. From the results of compressive stress and crystalline size, they indicate the optimal bias voltages are in the range of —40 to —80V. The maximum improvement in adhesion strength can be obtained as the oxygen flow rate at 6 sccm. The structure and morphology of this change can be studied by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES).
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Yi, Hsiu-Ping, and 易修平. "Establishment of an Indium tin oxide (ITO)-coated electrochemical device for monitoring the dynamic movements of ions and microbial rhodopsins." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/16691559971576207547.
Full textAbstract:
碩士國立臺灣大學
生化科技學系
101
Small charged molecules and ions play important roles in functioning proteins, including the cell signal transduction messenger Ca2+ and Na2+ and K+ for nerve impulse. In order to detect the movement of small charged molecules and ions in functioning proteins, an ITO (Indium tin oxide)-coated electrochemical device was adopted as one of the components when we designed a system to serve this need. In this bias-voltage free ITO-coated electrochemical system, we used a 6 to 8 kDa semi permeable membrane to separate the chamber intosample cell and reference cell, while the ITO-coated slides served as electrodes.The results showed we successfully employed ITO-coated electrochemical device to detect the light-driven proton and chloride signals of two light-driven ion pumps, bacteriorhodopsin and halorhodopsin, respectively. We also successfully detected the current signals caused by small charged molecules. We further used this device to investigate the relationship between mutated proteins and their functions. According to above results, this ITO-coated electrochemical device can be used to investigate the movement of small charged molecules and ions in functioning proteins in a quantive way.
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武紅幸. "The Investigation of Stress Behavior of Sputtered Indium Tin Oxide (ITO) Thin Films on Various Substrates and Substrate Effect on Optical Properties of ITO Film." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/91248251362529062365.
Full textAbstract:
碩士國立交通大學
材料科學與工程學系
99
Indium tin oxide (ITO) is a common transparent conductive layer in optoelectronic devices because of its high electrical conductivity and transparent in visible wavelength. Recently, with the development of flexible optoelectronic devices, polymer material is widely employed as the substrate in these devices due to its potential advantages of high flexibility, low cost, and light weight. However, once ITO film is formed onto polymer substrate, there is a significant stress induced in the ITO film because of polymer’s high coefficient thermal of expansion (CTE). A large film stress may result in poor durability, low conductivity, or low transparency. Thus, understanding the ITO film stress behavior onto various substrates is highly needed for its applications and reliability in flexible devices. In this study, the DC sputtered ITO film stress as a function of deposition temperature was investigated under multiple thermal cycling by using a bending beam technique. On various substrates such as Si, polyethylene terephthalate (PET) and ODPA-BAPP polyimide (PI), the room temperature formed ITO films exhibit a tensile stress. It was found that the film stress level strongly depends on the Young’s modulus of substrate. ITO stress achieves the lowest level as the film was deposited on PET. ITO film on Si has highest stress in the range of 80 – 330 MPa. The difference in stress level of ITO on various substrates is due to the fact that polymer substrate with lower Young’s modulus can plastically deform under ITO film stress, resulting in stress reduction of the ITO film. The critical stresses for cracking of ITO on polymer substrates were obtained as well, 19.2 MPa for ITO/PET and 75 MPa for ITO/PI, respectively. Different from the ITO films deposited at room temperature, ITO films deposited at 200 ºC on Si and PI are under less tensile stresses. The compressive tendency of film stress with increase in the deposition temperature can be attributed to a stronger ion peening effect and an improvement of film crystallinity. Beside the study of film stress behavior, transmittance and optical band gap of ITO film on glass, PET and PI substrates were investigated in order to understand any substrate effect on these importance characteristics of ITO film. An UV-visible spectrophotometer system was used to examine the transmittance of ITO film. The results show that ITO films on glass, PET and PI have similar transmittance nearly 90 % in the visible light region. However, the film optical band gap tends to narrow when coating on polymer substrates. Moreover, ITO on PET has larger optical band gap than ITO on PI presumably due to the less tensile stress of film on PET substrate.
46
Tzeng, Ping-Wei, and 曾評偉. "The Study and Fabrication of Indium Tin Oxide(ITO) Thin Films with High Work Function for Organic Light Emitting Diode Applications." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/12484434830598533210.
Full textAbstract:
碩士國立臺灣海洋大學
電機工程學系
93
At first, we investigated the effect of processing conditions on the characteristics of Indium Tin Oxide (ITO). In this thesis, oxygen flow and Tin doping content were the main variables. The experimental results showed that: As the oxygen flow was increased to 16sccm, and utilized a sintered ITO target (its ratio of In2O3 to SnO2 was 98 to 2) during the film deposition procedure, the work function can increase for more than 0.3 eV, but its resistivity increased 3 orders. In order to apply our high work function ITO to Organic Light Emitting Diode (OLED), we deposited untrathin high work function ITO (the thickness of this high work function ITO was less than 10nm) on the low resistivity ITO(the resistivity of this ITO was 1.1×10-3Ω.cm), and used this double layer ITO as anode of OLED. The structure of OLED were: glass substrate (0.7mm) /ITO(180nm) / NPB(40nm) /Alq3(60nm) /LiF(0.5nm) /Al(80nm). The results showed that : depositing ultrathin high work function ITO on low resistivity ITO, can improve the luminance efficiency. The maximum improvement was 24%. We also doped different kind of impurity (Zr and V) into ITO thin films. The experimental results showed that: As we doping 12.25%Zr into ITO films, the work function of ITO can be increased about 0.5eV, but its resistivity increased for more than 4 orders. In order to apply our high work function ITO to OLED, we deposited untrathin high work function ITO (the thickness of this high work function ITO was less than 10nm) on the low resistivity ITO(the resistivity of this ITO was 2×10-4Ω.cm), and used this double layer ITO as anode of OLED. The structure of OLED were: glass (0.7mm) /ITO(160nm) /NPB(40nm) /Alq3(40nm) / Mg:Ag(40nm). The results showed that : ITO anode with higher work function , can improve the improve the luminance efficiency. The maximum improvement was 18%. Key words: Indium Tin Oxide(ITO)、work function、Organic Light Emitting Diode (OLED)
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SEZEMSKÝ, Petr. "Deposition of functional thin films by plasma processes." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-262725.
Full textAbstract:
An aim of this work is a research of a deposition process of indium tin oxide by plasma assisted methods. The thesis deals with plasma diagnostics, e.g. Langmuir probe diagnostics and optical emission spectroscopy, as well as describes experiments of film deposition including their diagnostics, e.g. absorption spectroscopy, X-ray diffractometry and atomic force microscopy.
48
Fotsa-Ngaffo, Fernande. "Reactive pulsed laser ablation deposition (RPLAD) of indium tin oxide (ITO), titanium dioxide (TiO2) thin films and gold (AU) nanoparticles for dye sensitised solar cells (DSSC) applications." Thesis, 2008. http://hdl.handle.net/10539/4615.
Full textAbstract:
ABSTRACT
The focus of this work was the study possible ways to improve the efficiency of solar cells. To this end, the main aim was to investigate the deposition process of Indium Tin Oxide (ITO), Titanium Dioxide (TiO2), multi-layers ITO/TiO2 on quartz SiO2 substrates under different conditions (oxygen pressure, laser fluence and wavelength, and temperature) and later gold nanoparticles by the Reactive Pulsed Laser Ablation Deposition (RPLAD) technique. It was intended to investigate their electrical structural and optical properties under selected conditions for possible application to Dye Sensitised Solar Cells (DSSC).
Under optimised conditions, maximum deposition rates of 12nm/min for ITO and 21nm/min for TiO2 thin films were achieved. Rutherford Backscattering Spectrometry (RBS) with 2MeV He+ ions was used to measure the films thickness. Uniform thicknesses over a large area were found to be about 400nm and 800nm for ITO and TiO2 films, respectively. Crystalline properties were studied via x-ray diffraction and Raman spectroscopy. X-ray Diffraction (XRD) analysis revealed that the ITO films are highly orientated nanocrystals with their a-axis normal to the glass substrate surface. The average particle size of the precipitated nanocrystals was calculated to be 10-15nm.
The structure of the films was characterised via Atomic Force Microscopy (AFM) imaging of the top surface of the film. The films have a rough surface with average roughness of 26-30nm. Pores were observed with a density of 144 and 125 pores/mm2 and average size of 150 and 110nm for ITO films deposited at 200 and 400°C, respectively. TiO2 films deposited on the prepared ITO films were less crystalline. Annealing was performed at 300 and 500°C for 3 consecutive hours and the XRD results show that the transformation of TiO2 film into anatase phase was almost complete with a crystal size of ~ 6-7nm.
Scanning Transmission Electron Microscopy (STEM) of the surfaces was also performed. The TiO2 films deposited onto the prepared ITO films present a
relatively high pore size with an average pore diameter of ~ 40nm and excellent uniformity. It is interesting to note that the pores are randomly arranged. The random arrangement of the pores network may actually be beneficial for producing a uniform electrode. In addition, STEM cross-sectional analysis of the films showed a columnar structure but no evidence of voids in the structure. The large surface area produced suggests applications in DSSC.
The electrical properties of the films were investigated and an estimation of resistivity and Hall mobility was made. Low values of resistivity and high values of mobility were observed for ITO films. The resistivity of the film increases with increasing thickness while it decreases when increasing the deposition temperature. The lowest value was found to be 1.5x10-6Ωm for ITO films deposited at 400°C. Hall mobility was found to increase with substrate temperature. In this investigation, the highest Hall mobility at room temperature was estimated to be 22.3cm2/Vs under ambient O2 pressure (PO2) of 1Pa and 52.1 and 51.3cm2/Vs for films deposited at 200 and 400°C, respectively. But the best ITO film was deposited at 200°C, since this film combines good resistivity, good Hall mobility and good transmittance.
UV-VIS-IR transmission spectra were recorded on a Perkin Elmer Lambda 900. From the transmission data, the energy gap as well as the optical constant was estimated. A high transmission for ITO films in the visible (Vis) range was observed which was above 88% for films produced at room temperature and above 95% for those deposited at 200°C. The transmission for the films produced in oxygen was about 90% above 400nm, whereas it lies between 70 and 80% for films produced in rare gases. An increase in the band gap was observed by increasing the oxygen pressure and substrate temperature for ITO films. Increasing the quartz SiO2 substrate temperature from room temperature to 400 °C resulted in an increase of the transmission of TiO2 films, mostly in the Visible Near Infrared (Vis-NIR) from about 70% to 92%. After annealing at 500°C for 3 consecutive hours, the transmission of TiO2 film further sharply decreases toward shorter wavelengths.
Analysis of the transmittance curve of TiO2/Au shows a decrease of about 6% of the transmission in the Ultraviolet Visible (UV-Vis) range.
Optical absorption edge analysis showed that the optical density could be used to detect the film growth conditions and to correlate the film structure and the absorption edge. The TiO2 films deposited present a direct band gap at 3.51eV and 3.37eV for TiO2 as deposited and after annealing, respectively, while the indirect band gap was found to be 3.55eV and 3.26eV for TiO2 films as deposited and after annealing, respectively. There was a shift of about 0.1eV between as deposited ITO monolayer films and ITO/TiO2 bilayers deposited at 200°C. A small shift towards shorter wavelengths has been observed for multilayer ITO/TiO2/Au. In this case, the increase of Eg was ascribed to a reduction of the oxygen vacancies with increasing substrate temperature at which the ITO film was deposited.
The change in the shape of the fundamental absorption edge is considered to reflect the variation of density and the short range structural modifications undetected by structural characterisations. Enlargement of band-gap energies of semiconductors may be advantageous when used in DSSC to suppress the charge recombination between the reduced electrolytes and the photo-excited holes in the valence band of TiO2 substrates and enhance the open-circuit potential of the cell. When ITO/TiO2 bilayers were annealed before depositing Au, the gap energy remained constant.
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Τσικριτζής, Δημήτρης. "Μελέτη της επιφάνειας ITO-PET και της διεπιφάνειας NiPc/ITO-PET με φασματοσκοπίες φωτοηλεκτρονίων." Thesis, 2010. http://nemertes.lis.upatras.gr/jspui/handle/10889/4285.
Full textAbstract:
Σκοπός της παρούσας εργασίας είναι αρχικά να μελετηθεί η επιφάνεια του οξειδίου ινδίου κασσιτέρου που έχει αποτεθεί σε υπόστρωμα ΡΕΤ και να γίνουν πάνω σε αυτήν χημικές επεξεργασίες αλλά και ιοντοβολή, ώστε να παρατηρηθούν τι επιδράσεις έχουν αυτές οι κατεργασίες στην επιφάνεια και ενδεχομένως στο έργο εξόδου. Οι κατεργασίες επιλέχθηκαν επειδή είναι γνωστή από την βιβλιογραφία η επίδρασής τους στο ΙΤΟ που όμως έχει αποτεθεί σε γυαλί, και η σύγκριση με τα δικά μας αποτελέσματα θα δώσει χρήσιμες πληροφορίες για τις διαφορές των δύο υλικών καθώς και αν οι κατεργασίες αυτές μπορούν να χρησιμοποιηθούν και αν είναι χρήσιμες για την αύξηση του έργου εξόδου του ΙΤΟ-ΡΕΤ.
Επίσης, στη συνέχεια έγιναν αποθέσεις οργανικού ημιαγώγιμου υλικού (NiPc) πάνω στο υπόστρωμα ΙΤΟ-ΡΕΤ το οποίο είχε επεξεργαστεί χημικά, με σκοπό να προσδιοριστεί η ηλεκτρονική δομή της διεπιφάνειας του οργανικού και του υποστρώματος, ώστε να μελετηθεί η επίδραση του ΙΤΟ-ΡΕΤ στην συμπεριφορά της διεπιφάνειας και να διαπιστωθεί η πιθανή εφαρμογή τους σε ηλεκτρονικές διατάξεις.The purpose of this thesis is to study the surface of indium tin oxide deposited on PET substrate after some chemical treatments and Argon Sputtering, in to order to investigate what effects these treatments have on the surface and possibly in the work function. The treatments were chosen because it is known from the literature the influence they have on the ITO, but which it has been deposited on glass, and a comparison of our results will provide useful information about differences between the two materials, and whether these treatments can be useful for increasing the work function of ITO-PET. Also, it was deposited organic semiconductor material (NiPc) onto the ITO-PET substrate that was chemically processed in order to determine the electronic structure at the interface of organic substrate and to study the effect of ITO-PET in the behavior of interface and to determine its possible application in electronic devices.
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Alsaif, Jehad. "Parametric studies of field-directed nanowire chaining for transparent electrodes." Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/8463.
Full textAbstract:
Transparent electrodes (TEs) have become important components of displays, touch
screens, and solar photovoltaic (PV) energy conversion devices. As electrodes, they
must be electrically conductive while being transparent. Transparent materials are
normally poor conductors and materials with high electrical conductivity, such as
metals, are typically not transparent. From the few candidate materials, indium
tin oxide (ITO) is currently the best available, but indium is an expensive material
and ITO cost has risen with increasing demand. Therefore, alternative materials
or methods are sought to encourage production needs of applications and help in
reducing their price. This thesis presents and discusses results of experimental work
for a method, field-directed chaining, to produce a TE device which is nanowire-based,
with a figure of merit FoM= 2.39 x10E-4
Ohm E-1, comparable to ITO but with potential
for far lower cost.
Using electric field-directed chaining, multiple parallel long chains of metal nanowires
are assembled on inexpensive transparent materials such as glass by field directed
nanowire chaining, using methods first demonstrated in our laboratory.
In this work, we have improved the fraction of functional chains, by tuning the
field/voltage, a key step in increasing the FoM and lowering the cost. The effect
of operating parameters on TE optical and electrical properties has been studied and identified as well. From experiments with twenty seven substrates, each with
a range of electric field and nanowire concentration, the highest light transmission
achieved is 78% and the lowest sheet resistance achieved is 100 Ohm/sq. Among all
the operating parameters, the electric field has the most significant influence on the
fraction of nanowire chains that are functional. In the operating range of electric field strength available to us, we observed a monotonic increase in the fraction of
functional nanowire chains. We found a counter-intuitive change in TE properties in
a sub-range of nanowire concentration, associated with a change in the structure of
chained patterns.Graduate