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1
Proper, Sebastian. "Development of localized electrochemical deposition." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-302540.
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In the manufacturing industry, parts are created with high demands on their mechanical properties. To avoid surface defects, components are over-dimensioned and then machined to the desired size. This will give rise to material waste and extra processing steps. Therefore, it is of interest to investigate methods to repair these surface defects without the need of over-dimensioning. In this thesis work, different strategies for localized electrochemical deposition have been investigated with respect to their ability to perform local repair of surface defects. The concepts that have been studied include the application of a microanode, a confined bath, and of liquid marbles. The different methods were tested and the process parameters were optimized to achieve good quality deposits at sufficient growth rates. The best deposits were then further characterized with respect to grain size distribution, crystal orientation and surface quality. The ability to repair a surface defect was also studied along with the possibility of producing thicker deposits. The confined bath method was the most promising concept. At a current density of 3.5 A/dm2, a good quality deposit was achieved. The crystal orientations proved to be random and the average grain size was 115 ± 61 nm. A surface defect with a depth of 33.0 µm and a width of 19.8 µm was successfully repaired using this local deposition method. However, the technique needs further development for the desired application in manufacturing industry.
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Wagner, Mary Elizabeth S. B. Massachusetts Institute of Technology. "Advanced electrochemical characterization of copper deposition." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/110960.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, February 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 51-52).
The electrodeposition of copper metal in a concentrated sulfuric acid solution is reported to occur through a four-step mechanism: (I) the dehydration of Cu2+ (H2O)6, (II) the reduction of Cu2+ to cu+, (III) the dehydration cu+ (H2O)6-x, (IV) the reduction of Cu+ to copper metal. The dehydration steps have been found to be responsible for the pH-dependence of the electrodeposition reaction. It is also reported, although not well understood, that the presence of Fe2+ ions affects the reaction kinetics. In this work, the kinetics of copper electrodeposition were studied using alternating current cyclic voltammetry. The reaction was studied at a copper rotating disk electrode with varying concentrations of Cu2+ and Fe2+ . At sufficiently low pH, and a sufficiently high concentration of Fe2+ , the deposition kinetics may be slowed enough to separately observe the two electron transfer steps involved in copper reduction. It was found that Fe2+ ions affect the electrodeposition kinetic by slowing down reaction kinetics, particularly the second electron transfer reaction.
by Mary Elizabeth Wagner.
S.B.
3
Sawangphruk, Montree. "Electrochemical deposition and properties, of nanostructured materials." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526445.
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Corni, Ilaria. "Deposition of composite coatings by electrochemical means." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/11983.
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Tang, Zheng. "Polarized electrochemical vapor deposition (PEVD) and its applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/NQ34846.pdf.
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Eskhult, Jonas. "Electrochemical Deposition of Nanostructured Metal/Metal-Oxide Coatings." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8186.
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Suzuki, Y. "Controlled growth of nanostructure ZnO using electrochemical deposition." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1382395/.
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Zinc oxide (ZnO) has become a popular semiconducting material to study because of its wide applications. ZnO Nanorods (NR) in particular are very exciting features because of their unique properties which include the crystal dimensionality, highly optical transparency, tuneable electrical conductivity, integrity into pre-existing technologies and many others. Meanwhile, controlled and reliable synthesis of ZnO NR is still challenging and many methods have been proposed for a cheap growth of ZnO NR in large scale. Recently, electrochemically deposited ZnO film is attracting much attention, as it provides large-scale synthesis while ensuring a good electrical contact. This thesis studied the growth of a single nanostructure zinc oxide (ZnO) using electrochemistry, with special focus on the nanorod and their physical properties. In this work, ZnO was electrochemically deposited on ITO using mainly three electrochemical techniques: potentiodynamic (PD), potentiostatic (PS) and galvanostatic (GS). The time transient current and voltages were recorded in situ and analysed in depth. During our PD studies, we have identified different deposition mechanisms depending on the growth parameters, which are progressive and coalescent nucleation (NC). The Sharifker equation was the model used to describe PS ZnO progressive and NC process while nothing has been suggested for GS. Furthermore, we noticed that the same Sharifker model could no longer hold where the recorded current density was considerably high during the PS ZnO deposition. Here, we propose a model for GS ZnO deposition based on the electrical damping. We also suggest its adaptability for PS ZnO deposition when the charge transfer rate is comparably high. The physical properties of the nanorods were characterized using scanning electron microscope (SEM) and x-ray diffraction (XRD). The morphology of features at different deposition setups were studied and a parameter for was established for obtaining ITO covered with ZnO NR only. AFM and MATLAB program were also used to find a pattern of how for the size and the density of rods are distributed during the ZnO deposition on ITO. We have also investigated the crystal properties of deposited ZnO NR and we discovered that different deposition technique, or current density during the deposition, lead to different levels of Zn(OH)2 incorporation in the NR crystal which was confirmed with FTIR. The electrical conductivity was deduced using scanning tunnelling microscope (STM) at different tip heights, and was found to be 20 Ωcm with a carrier concentration of 3x1015 cm-3. Similar results were also obtained with a conductive atomic force microscope (AFM). In addition, two conduction mechanisms were observed depending on the crystallinity of the sample. The results show that electrochemically grown ZnO nanorods have electrical properties suitable with possibility of tailoring for use in optoelectronic devices such as diodes, varistors, solar cells and transistors. Few optoelectronic devices were designed based on the ECD grown ZnO. ASi: H p-i-n solar cells were deposited after the electrochemical deposition of ZnO on ITO-coated substrates. The results show that the textured solar cell performance was 30% higher than the planar solar cell. We also attempted flexible transparent ZnO based liquid-solid state solar cell (photoelectrochemical cell). Although a photoresponse was observed under UV, it had a poor charge collection efficiency (< 0.5%) which was attributed to the transparency and the thickness of ZnO layer.
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Allwright, Emily Marieke. "Electrochemical deposition of small molecules for electronic materials." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9921.
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The method of the deposition of films of small molecules for use in electronic applications is just as important as the molecule design itself as the film’s morphology and continuity influence the performance of the devices that they are incorporated in. The purpose of the work in this thesis was to develop a method of electrochemically depositing films of small molecules for potential use in electronic applications. A method of electrochemically depositing films of chemically reduced low solubility dye molecules was successfully pioneered. The process was developed using N,N dibutyl-3,4,9,10-perylene-bis(dicarboxime), a simplified version of 3,4,9,10-perylene-tetracarboxylic bisbenzimidalzole. Both of these dyes have been used in electronic applications, but low solubility makes them difficult to deposit by traditional solution techniques. A series of films was electrochemically deposited onto FTO coated glass and field effect transistors using coulometry. These films were characterised by absorption spectroscopy, photoluminescence, scanning electron microscopy, X-ray diffraction and photo-electrochemistry. The same deposition method was applied to copper phthalocyanine. These films were characterised by absorption spectroscopy, photoluminescence, scanning electron microscopy and X-ray diffraction. The developed method was used to deposit films of bilayers of dyes and to investigate the dye penetration during the deposition of copper phthalocyanine onto porous titanium dioxide. Films of neutral copper and nickel dithiolenes were electrodeposited from air-stable TMA salts to investigate the absorbance of the near infrared species formed, as well as to investigate the conductivity of both complexes and the magnetoresponse of the neutral copper dithiolene which is air unstable when formed chemically.
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Sharan, Kumar Varun. "Study of Binding Copper Powders by Electrochemical Deposition." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471346137.
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Sunitha, Radhakrishnan Shiv Shailendar. "Study of Localized Electrochemical Deposition Using Liquid Marbles." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479820546120994.
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Tay, En. "Electrochemical deposition of Cu-Zn-Sn-S films." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/30727.
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CZTS (Cu2ZnSnS4) solar cells offer an earth-abundant and non-toxic alternative to CIGS (CuIn1 xGaxSe2) and CdTe technologies. In a one-bath electrodeposition approach for CZTS, the wide deposition potential difference between Cu and Zn would result in dendritic morphology with poor adhesion to the substrate. This challenge was explored in Chapter 4 with three different additives (citric acid, thiosulfate, and thiourea) in pH 1.5 - 2.0, where Sn2+ is stable. Cyclic voltammetry was used to study reduction and oxidation peaks in electrolyte baths containing the metal ion and additive. Citric acid did not show significant complexing effect while thiosulfate and thiourea exhibited a negative shift in Cu deposition potential such that the deposition window is defined by Sn and Zn instead of Cu and Zn. In the pH range investigated, thiourea was found to be much more stable than thiosulfate, which decomposed to sulfur particles. With a suitable additive (thiourea) identified, a one-bath deposition of Cu-Zn-Sn was explored in Chapter 5. Electrolyte baths with Cu2+, Zn2+, Sn2+, and an additive was used for electrodeposition of films at -0.2 V, -0.5 V, -0.8 V, -1.1 V, and -1.3 V. Films deposited using thiosulfate showed weak adhesion to the substrate, and flaked off easily. Nanostructures obtained from citric acid and no additive exhibited were similar, highlighting an inactivation of citric acid at low pH values as suggested in literature. Nanostructures obtained from thiourea were different. In terms of film homogeneity, electrodeposition with thiourea resulted in films with improved surface coverage and less pinholes than the case with no additive and citric acid. The composition of the films exhibited a Sn incorporation from -0.5 V and below, and Zn incorporation from -1.1 V and below for citric acid and thiourea. Once films of Cu-Zn-Sn were obtained, sulfur was incorporated using co-deposition of metal ions and sulfur particles in Chapter 6. A comparison of continuous and pulsed co-deposition was explored and films obtained from pulsed co-deposition were found to exhibit significantly better film homogeneity, hence pulsed co-deposition was used for subsequent studies. Sulfur loading was increased from 0 g/L to 0.32 g/L and 0.64 g/L. The morphologies obtained from these films were similar, with sulfur incorporation increasing from 0 g/L to 0.32 g/L, with a slight increase from 0.32 g/L to 0.64 g/L. The results obtained from this work will be advantageous towards an economical one-bath electrodeposition approach for earth-abundant and non-toxic CZTS solar cells. In addition, this study is helpful for future possibilities of a multi-metal electrodeposition in a one-bath approach.
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Yau, Chun Ho. "Silver electrochemical-deposition on silicon nanowires, characterization & application." access abstract and table of contents access full-text, 2006. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?msc-ap-b21456306a.pdf.
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Thesis (M.Sc.)--City University of Hong Kong, 2006."Master of Science in Materials Engineering & Nanotechnology dissertation." Title from title screen (viewed on Nov. 21, 2006) Includes bibliographical references.
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Kulkarni, Dhananjay Vijay. "Electrochemical deposition of green rust on zero-valent iron." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/3753.
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Perchloroethylene (PCE) is a toxic contaminant that has been introduced into the environment over many years through industrial and agricultural wastes. Research has been done in the past to investigate PCE degradation by zero-valent iron (ZVI), green rust (GR) and a mixture of both. The combination of ZVI and green rust has been reported to be more effective for degrading PCE than either of them alone. Forming green rust electrochemically has the potential for depositing GR more effectively on the surface of ZVI where it will be able to more easily transfer electrons from ZVI to contaminants such as PCE. Therefore, the goal of this research was to determine the feasibility of electrochemically depositing green rust on zero-valent iron and to characterize it in terms of its composition, crystal properties and amount produced. XRD analysis was conducted to determine composition and crystal properties and a procedure was developed to measure the amount produced. Equipment was constructed to deposit green rust electrochemically onto ZVI. A chain of experiments with varying voltage, pH, time and amounts of ZVI were conducted to determine feasible experimental conditions for GR formation. Then, a method was developed to accurately measure the amount of surface oxides of iron deposited on the zero-valent iron substrate. This method was tested and found useful for measuring iron in: i) standard solutions of soluble iron with different concentrations of reagents; ii) suspensions with solid iron hydroxides by themselves; and iii) suspensions with solid iron hydroxides and ZVI. Electrochemical experiments were conducted and the amounts of iron hydroxides deposited on the ZVI surface were measured. XRD analysis of the deposits on the surface was conducted and the patterns of XRD-peaks were compared to that of type 2 Â sulfate green rust.
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Choong, C. L. "Electrochemical deposition of polymeric nanostructures and their biosensing applications." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597639.
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Free-standing carbon nanotube or fiber (CNT/CNF) arrays were employed to template the growth of molecular (caffeine) imprinting polymer. The vertically aligned CNT/CNFs were deposited by plasma enhanced chemical vapour deposition (PECVD) onto different metallic buffer layers on silicon substrates. In the selection of the metallic buffer layer, titanium outperformed other metals in term of its electrical conductivity, adhesion and CNT yield. Direct deposition of sparse CNT arrays, with approximately half a micron tube-to-tube spacing, and dense CNT forests were developed. When these new CNT-polymer architectures were employed in amperometic sensing of caffeine molecules, an increase in sensitivity with the packing density of CNT was observed. In templateless synthesis, the shape-controlled growth mechanism of polymer nanocrystals was studied using chitosan biopolymer. It was found that the 10 to 20 nm sized nanoparticles in the growth solution were the basic building blocks in the formation of the nanocrystals. In general, a large number of nanoparticles which are free from chain entanglement produced a high yield of nanocrystals. The shape of the chitosan nanocrystals could be controlled through the nanoparticle concentration and the applied potential. For biosensing applications, the electrically stimulated actuation of conducting polymers (CP) was first explored in developing a new concept of smart sensing. The smart sensing was achieved by modulating the detection window of a CP based biosensor to accommodate the measuring range of a specific test solution. This new concept was experimentally investigated using a submicron thick biocompatible CP, polypyrrole, with molecular (caffeine) imprinting for caffeine detection. The modulation of the detection window was observed by varying the application pulsed potential of these biosensors.
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Balsamy, Kamaraj Abishek. "Study of Localized Electrochemical Deposition for Metal Additive Manufacturing." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1539078938687749.
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Ge, Xiang. "Electrochemical deposition of fluoridated calcium phosphate on titanium substrates /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?MECH%202008%20GE.
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Attygalle, Dinesh. "Electrochemical Deposition of Transparent Conducting Oxides for Photovoltaic Applications." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1229464154.
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Mao, B. W. "In-situ X-ray diffraction studies of electrochemical interfaces." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378678.
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Liu, Ran. "Synthesis, characterization and properties of nanostructured materials by template-directed method." ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,141.
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Thesis (M.S.)--University of New Orleans, 2004.Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Chemistry."--Thesis t.p. Vita. Includes bibliographical references.
20
Deng, Hua. "Electrochemical Deposition of Nanocrystalline Copper and Copper-Based Composite Films." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020103-173702.
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Free-standing nanocrystalline copper-based composite and particle-free copper films were produced by direct- and pulse-current plating. Nanosize 50-nm Al2O3 or 5-nm diamond particles were codeposited into a copper matrix prepared on a rotating disk electrode (RDE). The electrolytes contained CuSO4.5H2O (0.25 M), H2SO4 (0.56 M or 1.5 M), 50-nm Al2O3 (12.5 g/L or 1.0 g/L) or 5-nm diamond (0.5 g/L) particles, and gelatine (0.1 g/L, 0.05 g/L, or 0.02 g/L). The deposition was carried out at room temperature. The RDE was rotated at 1800 rpm for high-alumina particle baths (12.5 g/L) and 1000 rpm for low-alumina particle (1.0 g/L), diamond particle (0.5 g/L), and particle-free baths. The free-standing composite and copper films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), micro hardness tester, and transmission electron microscopy (TEM). Grain size and crystal texture were obtained by XRD measurement. SEM gave information on surface morphology and composition of films. The hardness of nanocrystalline materials was measured by micro hardness tester. TEM was used to confirm the presence of nanocrystalline copper grains. The uncompensated potential became more cathodic with increasing current density in pulse-current plating. The current efficiency was in the range of 0.93 ¨C 1.09 for both direct- and pulse-current plating. Gelatine concentration, the presence of nanosize dispersoids, and pH have no significant effect on electrode potential and current efficiency. Grain size decreased with increasing current density for particle-free copper and most of the composite films by direct- and pulse-current plating. The microhardness of nanocrystalline materials was increased by decreasing grain size for most of the particle-free copper and composite films. The existence of high-angle grain boundaries in nanocrystalline films resulted in negative Hall-Petch slopes. The presence of low concentration of alumina or diamond particles had no effect on grain size and microhardness. The pH had no obvious influence on grain size, microhardness, and alumina content in composite films. Random crystal texture is observed for Cu-Al2O3 composite and particle-free copper films and the (111) preferred texture for Cu-diamond composite films. The (100) preferred substrate orientation had no effect on deposit texture. The current density for both direct- and pulse-current plating had no significant effect on material texture. The presence of particles has no significant influence on nanocrystalline texture. Surface morphology varied for films made under different bath conditions. High gelatine concentration resulted in low-particle impregnation. Films made using 0.1 g/L gelatine resulted in spherical particles with grain size of 64 nm and porous surface. Films made using 0.02 g/L gelatine resulted in smooth surface with smaller grains of 40 nm. Films with high-alumina particle embedding, for example sample 7/9-1, resulted in porous and dark surface. High-alumina particle concentration (12.5 g/L) with 0.02 g/L gelatine in the deposition baths resulted in high-alumina content (0.11 wt% - 2.76 wt%) in composite films. The higher current density (297 mA/cm2) resulted in the lower alumina particle (0.076 wt%) embedding rate for the same bath parameter setting. The presence of both Al and O was found in copper-alumina composites and C element (diamond) was detected in copper-diamond composite films by EDS.
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Rostek, Raimar [Verfasser], and Peter [Akademischer Betreuer] Woias. "Electrochemical deposition as a fabrication method for micro thermoelectric generators." Freiburg : Universität, 2016. http://d-nb.info/1122647638/34.
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Madden, John David Wyndham. "Fabrication of three dimensional micro-structures by localized electrochemical deposition." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22661.
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A new microfabrication technology capable of electro-depositing truly three dimensional metal micro-structures is presented. The method, known as Spatially Constrained Micro-Electro-Deposition or SCMED, is being developed as part of an effort to provide sub-millimeter sized tools and extra degrees of freedom to existing tele-operated micro-surgical robots and micro-manipulators. These applications require fabrication processes capable of producing three dimensional structures, with sub-micrometer spatial resolution, using a range of materials and at reasonable rates. Current micro-fabrication technology is,unable to meet these requirements. The three dimensional requirement is particularly relevant given the present dependence on essentially two dimensional micro-fabrication methods derived from micro-electronics.In SCMED, electrodeposition is localized by placing a sharp tipped electrode in a plating substrate, and applying a voltage. Structures are built by moving the electrode appropriately with respect to the substrate.
Electrochemical theory, including mass transport to regions of localized field, is discussed, and a model of deposition profile presented. SCMED is shown to be capable of producing three dimensional polycrystalline nickel structures on the micrometer scale, including a multi-coiled helical spring. Vertical deposition rates of 6 $ mu m$/s are observed, two orders of magnitude greater than those of conventional electrodeposition.
The process can potentially deposit and etch a wide rage of materials including pure metal, alloys and polymers with sub-micrometer resolution, thereby overcoming important limitations or current technology.
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Worrall, Stephen. "Anodic deposition of metal-organic framework coatings for electrochemical applications." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/anodic-deposition-of-metalorganic-framework-coatings-for-electrochemical-applications(89a9a8b8-161d-428c-896c-4d0acbb72f4c).html.
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The electrochemical growth of metal-organic framework (MOF) coatings, utilising the anodic dissolution method, has been investigated as a means of preparing MOF coated electrodes for various electrochemical applications. A mechanistic understanding of the formation of the electrode coatings has been further developed. This understanding has been utilised to expand the scope of this technique; to allow for the electrochemical formation of Zn and Co zeoliticimidazolate framework (ZIF) coatings which was hitherto not believed to bepossible. Electrodes coated with Co and Zn ZIFs via this methodology were assessed for their capacitive behaviour and the Co ZIFs exhibited the highest, pure MOF areal capacitance values reported to date. This was attributed to the method of coating formation, which provides well adhered coatings of MOF particles integrated into the electrode surface providing a good electrical connection between the coating and the electrode. Incorporation of GO, via electrophoretic deposition during the coating growth, is shown to improve this capacitance still further. Thecorresponding Zn ZIFs exhibited resistances orders of magnitude higher than their Co analogues; modelling can explain this behaviour with the Co analogue of a given ZIF calculated to have a greater metal contribution to its LUMO leading to a more delocalised electronic structure. Electrodes coated with the Cu MOF HKUST-1 have enabled for the first time the use of MOFs as a template for the electrodeposition of anisotropic metal nanostructures. Such MOF encapsulated metal nanostructures are demonstrated to have applications in surface enhanced Raman spectroscopy (SERS). In addition the same MOF has been discovered to display a redox based hysteresis which allows for the rewritable storage of small amounts of electrically accessible data.
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Шумакова, Наталія Іванівна, Наталия Ивановна Шумакова, Nataliia Ivanivna Shumakova, and Z. M. Protsenko. "Electrochemical Deposition of Film Materials Based on Co and Ag." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35008.
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The technology deposition of film materials with spin-dependent scattering of electrons based on Co
and Ag by electrochemical method from sulfate and iodide electrolytes described. The kinetics of electroreduction
of Co and Ag from this electrolytes. Determined phase composition of multilayer coatings based on
Co and Ag before and after thermal annealing to temperatures T = 523-743 K.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35008
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Plana, Daniela. "An electrochemical investigation of electroless deposition : the copper-DMAB system." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/an-electrochemical-investigation-of-electroless-deposition-the-copperdmab-system(8478ea99-e05f-40c6-8260-2e8788f38efa).html.
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An electrochemical study of the copper electroless deposition process, using dimethylamine borane as a reducing agent, has been performed, in order to gain further understanding of the mechanism and kinetics of electroless deposition. An in-depth study of the electro-oxidation of dimethylamine borane (DMAB) was additionally carried out, due to its increasing relevance, not only in electroless deposition, but also in fuel cell technology. DMAB oxidation was studied using different experimental techniques such as voltammetry, chronoamperometry, single-crystal electrochemistry and in-situ Fourier Transform infrared spectroscopy, which demonstrated that adsorption of the DMAB molecule, and its intermediates, plays an important role in the oxidation mechanism and kinetics. The initial dissociation process is catalysed by the presence of metallic surfaces and the applied potential. On gold surfaces, DMAB undergoes a three-electron transfer at low overpotentials, with a further oxidation process of up to six electrons occurring at high overpotentials. Chemical interactions with gold oxide produce further oxidation of the DMAB molecule. In the potential region of gold oxide formation, in highly alkaline media, the dimethylamine is also oxidised. The voltammetric behaviour of bipolar cells was studied using model reversible and quasi-reversible redox couples, in conjunction with numerical simulations of the system. DMAB oxidation and copper electrodeposition were studied separately and together using the bipolar cell, providing useful information of the 'coupling' effects between the cathodic and anodic processes of electroless deposition. The ability to quantify side reactions associated with electroless plating, namely hydrogen evolution in the copper-DMAB system, was also demonstrated. The kinetics of the copper-DMAB electroless system was studied in detail, using the electroless bath and a galvanic cell configuration. The fact that the rate of deposition decreased upon the physical separation of the two half-reactions, as well as the observed catalysis of the oxidation of DMAB by copper surfaces, lead to the conclusion that the mixed potential theory (MPT) does not apply to this system. Faradaic efficiencies never reached 100% due to the parasitic side reactions mentioned above; the latter were especially prominent in the early stages of deposition. Crystalline copper films were obtained, with a higher fraction of Cu (111) than expected for polycrystalline copper, while the roughness of the deposits was found to increase with deposition time.
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Venkatraman, Kailash. "Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1543839404490434.
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Lin, Po-Fu. "Electrochemical Quartz Crystal Microbalance Study Of Bismuth Underpotential Deposition On Ruthenium And On Electrochemically Formed Ruthenium Oxide." Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc103354/.
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Kinetics and thermodynamics of bismuth (Bi) underpotential deposition (UPD) on ruthenium (Ru) and on electrochemically formed Ru oxide are studied using electrochemical quartz crystal microbalance technique. The Bi UPD and Bi bulk deposition are observed both on Ru and on electrochemically formed Ru oxide electrodes. The anodic peak potential of Bi UPD shifts slightly to positive potential as the scan rate increases. The peak current ratio (IAnode/ICathode) of Bi UPD and Bi bulk increases as the scan rate increases. Bi monolayer coverage calculated from mass (MLMass) and from charge (MLCharge) with scan rates dependent are compared both in Bi UPD region and in Bi bulk region. Stability and oxidation time effects are also investigated. Bi UPD on Ru and on electrochemically formed Ru oxide are quasi-reversible, scan rate independent, oxidation time dependent, and have higher plating efficiency on Ru. However, Bi bulk deposition on Ru and on electrochemically formed Ru oxide are quasi-reversible, scan rate dependent, oxidation time independent, and have higher plating efficiency on electrochemically formed Ru oxide. Both Bi UPD adatoms and Bi bulk are unstable in 0.5M H2SO4.
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Lindh, Mattias. "Inkjet deposition of electrolyte : Towards Fully Printed Light-emitting Electrochemical Cells." Thesis, Umeå universitet, Institutionen för fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-80272.
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Organic electronics is a hot and modern topic which holds great promise for present and future applications. One such application is the light-emitting electrochemical cell (LEC). It can be fully solution processed and driven at low voltage providing light emission from a large surface. Inkjet printers available today can print a variety of inks, both solutions and dispersions. The technique is scalable and a quick and easy way to accurately deposit small quantities of material in user definable patterns onto a substrate. This is desirable to make low cost and efficient optical devices like displays. In this thesis it has been shown that solid electrolytes, after being dissolved in a liquid solvent, can be inkjet printed into a set of well separated distinct drops with an average maximum thickness of 150 nm. The electrolytes are commonly used in LECs and comprised by poly(ethylene glycol) with molar masses ranging from 1 – 35 kg/mol, and potassium trifluoromethanesulfonate (KCF3 SO3 )—together dissolved incyclohexanone to form an ink. The smallest achieved edge to edge distance between the printed drops was 40 μm. Together with a drop diameter of 50 μm it yields a coverage of 24% at a resolution of 280 dpi. Profiles of dried deposited drops of electrolyte were examined with a profilometer, which showed adistinct coffee ring effect on each drop. In particular, the ridges of the coffee rings were broken into pillar like shapes, together forming a structure akin to a scandinavian ancient remnant called stone ship. Different drop diameters were measured in and between the indium tin oxide samples. The drops’ speeds and sizes atejection from the nozzles seemed unchanged, and wettability is most probably the physical phenomena tolook into in order to understand what generates the differences. Local changes in surface roughness and/or surface energy, possibly originating from the cleaning process of the samples, is most likely the cause. No indications towards large differences in surface tension between the printable inks were seen, however their viscoelastic properties were not measured. As part of the thesis work a LEC characterization set-up was built. It drives a LEC at constant currentand measures the driving voltage, -current, and luminance over time. The set-up is controlled by a Labview virtual instrument and the data exported to a text-file for later analysis. The precision of the luminance measurements is ±0.1 cd/m2 for readings < 50 cd/m2 , but the accuracy is uncertain. The conclusion of this thesis is that it is indeed possible to print solid electrolytes dissolved in cyclo-hexanone with an inkjet printer. However, in order to fully understand the spreading and drying of thedrops, studies of the inks’ viscoelastic properties, together with surface roughness and -energy density ofthe substrates, are needed. The largest molar mass of nicely printable poly(ethylene glycol), at an ink concentration of 10 mg/ml, was 35 kg/mol. This is comparable to the molar mass of an active light-emittingmaterial, “SuperYellow”, often used in LECs. Even though their respective molecular structures are very different, this indicates that inkjet printing of complete LEC-inks, containing both the active material and solid electrolyte, is feasible. Most probably it would require substantial tuning of the printing parameters. This thesis provides further hope for future fully inkjet printed LECs.
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Hyde, Michael. "Scanning probe microscopy and electrochemical studies of deposition on electrode surfaces." Thesis, University of Oxford, 2005. http://ora.ox.ac.uk/objects/uuid:f8690b52-766f-4f9a-9178-708d50755f09.
Full textAbstract:
SPM, optical microscopy, and electrochemical techniques are used to study a range of electrochemical deposition processes on carbon electrodes, particularly those associated with diffusion-controlled multiple nucleation. Anodic stripping voltammetry for analytical measurements using solid electrodes is addressed in the light of limitations arising from electrode heterogeneity, electrode morphology, inhibited electrodeposition, and incomplete stripping of deposited metal. It is shown, using direct imaging of electrode surfaces, that each of the preceding factors may produce significant deviations from ideal electrode behaviour. The electrochemical nucleation of silver on BDD is examined. Data are obtained for the nucleation rate by interpretation of the deposition voltammetry, and by inspection of in-situ optical microscopic images. The particle distributions are analyzed and a stochastic model of nucleation developed. A model for the potentiostatic nucleation and three dimensional growth of deposits on an electrode surface under hydrodynamic conditions is examined. A wall-tube and stirred cell are used to generate conditions in which the diffusion layer thickness is in the range 10 – 40 μm. It is shown that the model provides excellent fits to the experimental data. A previously unrecognised correlation between the morphology of the PbO2 deposits and their electrocatalytic activity is established. The morphology of the films are observed as a function of time and potential using in-situ AFM. Nanotrench arrays are fabricated on HOPG surfaces. Cyclic voltammetry in simple redox couples is used to provide experimental evidence that the voltammetric response of a graphite electrode is solely due to the edge plane sites, with the basal plane sites having no measurable contribution. Nanotrenches are used as templates in a simple method for generating random assemblies of metal nanobands. This method is shown to be effective for generating gold, silver and copper nanowires. The electrochemical properties of the array are investigated via cyclic voltammetry.
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Flores, Araujo Sarah Cecilia. "Electrochemical Study of Under-Potential Deposition Processes on Transition Metal Surfaces." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5372/.
Full textAbstract:
Copper under-potential deposition (UPD) on iridium was studied due to important implications it presents to the semiconductor industry. Copper UPD allows controlled superfilling on sub-micrometer trenches; iridium has characteristics to prevent copper interconnect penetration into the surrounding dielectric. Copper UPD is not favored on iridium oxides but data shows copper over-potential deposition when lower oxidation state Ir oxide is formed. Effect of anions in solution on silver UPD at platinum (Pt) electrodes was studied with the electrochemical quartz crystal microbalance. Silver UPD forms about one monolayer in the three different electrolytes employed. When phosphoric acid is used, silver oxide growth is identified due to presence of low coverage hydrous oxide species at potentials prior to the monolayer oxide region oxide region.
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Rodrigues, Patrícia Raquel dos Santos. "Development of oxidoreductase based electrochemical biosensors." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10427.
Full textAbstract:
Dissertação para obtenção do Grau de Mestre em
BiotecnologiaThis thesis is divided in 2 sections, each describing the development of an oxidoreductase based biosensor. In the first part human Cytochrome P450 1A2 (CYP1A2) electrochemistry was studied, while the second is focused on the optimization of immobilization platforms and operation methods for amperometric biosensors, using cytochrome c nitrite reductase (ccNiR), (Desulfovibrio desulfuricans ATCC 27774) as a model enzyme. The direct electrochemistry of P450s immobilized in water-based sol-gel thin films was described for the first time. The optimization of the film showed that only the combination of the inorganic matrix and the PEG400 enabled the direct electron transfer reaction and electrocatalytic activity towards oxygen. The amount of dissolved oxygen in solution revealed itself a significant feature in CYP’s electrochemistry – in anaerobic conditions, when small amounts of oxygen are added the PFeIII=II signal’s intensity increased, while in aerobic conditions it disappeared; probably PFeIII is not being regenerated. However, this was not observed with the CYPOR complex, indicating that the reductase has an essential role in the CYP’s catalytic cycle completion; this was also sustained by the fact that only in its presence organic substrates catalysis (caffeine) occurs. The hybrid sol-gel developed for CYP, was optimized for a nitrite biosensor. ccNiR was successfully incorporated while promptly displaying catalytic currents. Although the bioelectrode’s response decreases after day one, it was able to maintain a reasonable catalytic activity over a time span of 2 weeks. Another electrode modification strategy, studied with ccNiR, was based on the electrophoretic deposition of macroporous assemblies of single-walled carbon nanotubes. The macroporous structure was created as a result of the presence of polystyrene beads co-deposited with the carbon nanotubes. An increase in the amount of material was correlated with a higher enzyme activity. Finally, an oxygen scavenger system consisting of glucose oxidase, glucose, and catalase was employed for oxygen removal in an open electrochemical cell. The system completely removed oxygen for over 1 h and was successfully applied to a ccNiR based nitrite sensor.
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Gouldstone, Andrew. "Electrochemical vapor deposition of a graded titanium oxide-yttria stabilized zirconia layer." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39612.
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Wheeldon, Ruth. "Electrochemical aspects of the deposition of refractory metal carbides from molten chlorides." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47705.
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Daugherty, Ryan E. "Electrochemical Deposition of Nickel Nanocomposites in Acidic Solution for Increased Corrosion Resistance." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011756/.
Full textAbstract:
The optimal conditions for deposition of nickel coating and Ni-layered double hydroxide metal matrix composite coatings onto stainless steel discs in a modified all-sulfate solutions have been examined. Nickel films provide good general corrosion resistance and mechanical properties as a protective layer on many metallic substrates. In recent years, there has been interest in incorporation nano-dimensional ceramic materials, such as montemorillonite, into the metal matrices to improve upon the corrosion and mechanical properties. Layered double hydroxides have been used as corrosion enhancer in polymer coatings by increasing mechanical strength and lowering the corrosion rate but until now, have not been incorporated in a metal matrix by any means. Layered double hydroxides can be easily synthesized in a variety of elemental compositions and sizes but typically require the use of non-polar solvents to delaminate into nanodimensional colloidal suspensions. The synthesis of a Zn-Al LDH has been studied and characterized. The effects of the non-polar solvents dimethylformamide and n-butanol on the deposition and corrosion resistance of nickel coatings from a borate electrolyte bath have been studied, a nickel-LDH nanocomposite coating has been synthesized by electrochemical deposition and the corrosion resistance has been studied. Results indicate an improvement in corrosion resistance for the coatings with minimal change in the nickel matrix's internal strain and crystallite size.
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Wang, Chen. "The Revival of Electrochemistry: Electrochemical Deposition of Metals in Semiconductor Related Research." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc5574/.
Full textAbstract:
Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V versus Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test", which involves sticking the scotch tape on the sample, then peeling off the tape and observing if the copper film peels off or not. Characterization by scanning electron microscopy (SEM)/energy dispersive X-ray (EDX) and X-ray photon spectroscopy (XPS) confirmed the presence of metallic Cu, with apparent dendritic growth. No sulfur impurity was observable by XPS or EDX. Kinetics measurements indicated that the Cu nucleation process in the sulfuric bath is slower than in the borate bath. In both baths, nucleation kinetics does not correspond to either instantaneous or progressive nucleation. Films deposited from 0.05 M CuSO4/H2SO4 solution at pH > 1 at -0.2 V exhibited poor adhesion and decreased Cu reduction current. In both borate and sulfate baths, small Cu nuclei are observable by SEM upon deposition at higher negative overpotentials, while only large nuclei (~ 1 micron or larger) are observed upon deposition at less negative potentials. Osmium metal has been successfully electrodeposited directly onto p-Si (100) from both Os3+ and Os4+ in both sulfuric and perchloric baths. This electrochemical deposition of osmium metal can provide sufficient amount of osmium which overcome ion beam implantation limitations. The deposited metal can undergo further processing to form osmium silicides, such as Os2Si3, which can be used as optical active materials. The higher osmium concentration results in large deposition currents and more negative peak potential due to larger transfer coefficient. No matter which supporting electrolyte is used, no stripping peak exists in this study. The oxidation ability of anion plays an important role in osmium electrodeposition because it will change the silicon substrate conductivity. In our case, perchloric acid oxidized silicon surface severely. Os4+ seems more favorable for reduction but has a stronger oxidization ability to lower the conductivity. The microscopic images verified osmium is deposited on silicon and forms cluster sizes of < 1 µm to > 10 µm. The Rutherford backscattering spectroscopy (RBS) data indicate osmium can diffuse into the silicon as far as 500 nm and the Si crystal structure is unchanged by the process. This means that the Si does not disassociate and migrate into deposited Os. Osmium is distributed randomly throughout the lattice interstitially. It appears field assisted diffusion can significantly drive the Os into Si (100). This finding is very valuable but needs further study.
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YA, HUNG CHUEN, and 洪雀雅. "Electrochemical Deposition of BaTiO3 Films." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/68392818941404624766.
Full textAbstract:
碩士國立中興大學
材料工程學研究所
88
Abstract The aim of this research is to fabricate BaTiO3 films by the electrochemical method in the electrolytes, 0.35M/0.5 M Ba(CH3COO)2 and 2M NaOH. The pH value was greater than 13.5 and the deposition temperature was controlled at 55°C. We firstly applied the scanning current mode varying from 0 to 100 mA to deposite BaTiO3 films in the electrolyte of 0.35M Ba(CH3COO)2 and 2M NaOH to find the suitable deposition conditions. Secondly, we. used a fixed electric content, 432 C to prepare the films. XRD results show that the crystal structures of the films are TiO2 (rutile phase) at 10 mA and BaTiO3 (cubic phase) at 20, 30 and 40 mA. We varied the deposited time from 0.5 to 4 hr at constant current of 30 mA in the electrolyte of 0.5 M Ba(CH3COO)2 and 2M NaOH. TiO2 (rutile phase) existed at 0.5 hr and BaTiO3 (cubic phase) appeared above 1 hr. We believed that TiO2 appeared before the formation of BaTiO3. The optimized condition for depositing BaTiO3 films follows: anodic current at 30 mA and deposited time at 4 hr, where, the thickness of BaTiO3 films reached about 20 mm. The growth of BaTiO3 films possessing small grain size which was formed at low voltage range could be due to the dissolution-recrystallization mechanism. The large grained BaTiO3 films formed at high current (voltage) could attribute to size anodic spark deposition.
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Shue, Shiun-Feng, and 許薰丰. "Deposition of Hydroxyapatite by Electrochemical Process." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/28145044908725572091.
Full textAbstract:
碩士國立成功大學
材料科學(工程)學系
86
Hydroxyapatite was deposited on titanium substrate by electrochemical process with pulse power supply. The electrolyte used for electrochemical deposition was prepared by mixing 1L 0.042M Ca(NO3)2and 1L 0.025M NH4H2PO4 solutions. The cathode and anode were titanium substrate and platinum respectively. Various ratios of the time of voltage ON / the time of voltage OFF and various periodic times for pulse power supply were used to cause the ions of the electrolyte well distribution and obtain a hydroxyapatite coatings without introducing other impurities. Then the growth of coatings and the change of coatings after soaking in simulated body fluid were studied. The results show that, when the temperature of electrolyte and the time of deposition are fixed at 40℃and 24 hours respectively, a hydroxyapatite coatings can be obtained without introducing other impurities by the input voltage consisting of 2-s voltage on / 18-s voltage off cycles with an amplitude of 20V. So the growth of coatings by this type of pulse power supply was investigated. The precipitate on the titanium substrate is an amorphous phase at the initial stage of deposition. The crystallization of hydroxyapatite becomes well with the time of deposition. The hydroxyapatite structure contains CO32- and HPO42- groups. The grain size smaller than 1*m of the coatings and the thickness of 30μm can be obtained for 30 minutes deposition. The hydroxyapatite coatings can induce the Ca2+ and PO43- ions to precipitate from the simulated body fluid. The precipitate is an amorphous phase at the initial stage then transforms to hydroxyapatite structure. The ratios of Ca/P obtained is between 1.37 to 1.441.
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Xu, Xun-Feng, and 許薰丰. "Deposition of Hydroxyapatite by Electrochemical Process." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/85909404449242106483.
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Lin, Po-Yuan, and 林博淵. "Nanocrystalline cuprous oxide by Electrochemical Deposition." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/22161110700425733801.
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碩士建國科技大學
電子工程系暨研究所
100
Nanocrystalline cuprous oxide (Cu2O) thin films were deposited on conducting tin oxide coated glass plates by electrochemical deposition method at different electrode potential, solution pH, solution concentration, deposition time and temperature. These as deposited films were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Atomic force microscope (AFM), UV-Visible spectrophotometer (UV-Vis), Four-point electrical measurements and Ellipsometer techniques to reveal their structural, morphological and optical properties. The quality of these films was compared and their deposition parameters were optimized. X-ray diffraction results showed that the structural is a mixed structure amorphous/polycrystalline and the preferred orientations along (200) and (111). Moreover, the average grain sizes of the polycrystalline films estimated using Scherrer formula ranged from 20-80 nm. The surface of the Cu2O film becomes rougher as the deposition temperature, solution pH and deposition time increases. The resistivity is minimized to 24.1 Ω-cm when the Cu2O film is grown at room temperature, -0.9 V versus SCE, 9±0.1 pH and the average transmittance in the visible light region is ∼65%. The optical band gap decreases as the deposition temperature increases.
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Huang, Yu-An, and 黃佑安. "Anodically electrochemical deposition of nanostructured nickel oxide electrodes for electrochemical capacitors." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/85015557427157811101.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程系碩士班
96
The goal of this research is to deposit nanoporous nickel oxide film by anodically electrochemical deposition route .Their electrochemical performances after annealing at different temperatures are investigated. In addition, the influence of deposition parameters, current and potential,on the specific capacitance of deposited nickel oxide films. Crystal structure of the film deposited at constant current and potential is mainly composed of nickel hydroxide. However, it changes to nickel oxide after annealing at higher temperatures. After XRD analysis, it suggests that there is an apparent change at the annealing temperature of 300℃ that nickel hydroxide changes to nickel oxide . The SEM image shows that the surface morphology of nickel oxide film is highly porous and composed of interconnected nanoflakes. When smaller current or potential is applied, the pore of film is larger. On the other hand, while larger current or potential is applied, the pore of film is smaller. The pore size can be controlled without by deposition parameter such as current and potential mesoporous templates or carbon nanotubes. The capacitor behavior measured by CV and AC impedance shows that an optimum the capacitance behavior of the electrode is obtained after annealing at 300℃. The specific capacitance of the deposited film is about 260 Fg-1, which is much higher than that of deposited by electrochemically cathodic deposition (59Fg-1) reported in literature.
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Ho, Chia-Ling, and 何佳玲. "Electrochemical behavior of macroporous manganese oxide electrodes prepared by electrochemical deposition." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40964400279850333906.
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碩士國立高雄應用科技大學
化學工程與材料工程系
98
In this study, the monodispersed polystyrene (PS) spheres are used as the template in anodic electrodeposition to form macroporous manganese oxide electrode. The effects of electrode’s structure on the electrochemical behavior are investigated. Field-emission Scanning electron microscope (FE-SEM) and glancing angle X-ray diffraction (GA-XRD) were used to identify the film surface morphology and crystal structure. The electrochemical performances of the films are characterized by means of cyclic voltammetry, galvanostatic charge/discharge and cycle-life test in 1 M Na2SO4 electrolyte. The SEM image shows that the morphology of manganese oxide film is composed of nanowires. The macroporous, hollow and conductive porous MnO2 electrodes can be obtained by tuning the fabricating process. GA-XRD analysis shows that the crystal structure of the film annealed at 300oC is MnO2 . Porous film structure can enhance significantly the specific surface area and the utilization of MnO2 due to the facilitation of electrolyte penetration and migration through film. Hence, the porous structure has positive effects on the capacitive behavior of film. In addition, depositing the conductive NiO film onto the PS sphere by electrophoretic deposition (EPD) can enhance the capacitive behavior of MnO2 film possibly due to an increased electrical conductivity of film. The electrochemical results show that the specific capacitance of the macroporous, hollow and conductive MnO2 electrodes are approximately 288 Fg-1, 504 Fg-1 and 472 Fg-1, respectively, which are much higher than that of a bare MnO2 film deposited by anodic deposition (257 Fg-1).
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Wang, Min-Jyle, and 王明詰. "Porous nickel oxide electrodes prepared by electrochemical deposition and their electrochemical behavior." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18416470257053007312.
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碩士國立高雄應用科技大學
化學工程與材料工程系
97
In this study, nickel oxide (NiO) is deposited onto the stainless steel (SS) substrate by anodic electrodeposition with addition of surfactant. The changes in electrode morphology by adding surfactants are investigated. In addition, the influences of deposition parameters, such as current density and potential, on the specific capacitance of deposited NiO films are also studied. In order to discuss the effects of macroporous NiO structure on the electrochemical performance of electrode, polystyrene spheres with 200 nm in diameter (PS) are deposited on SS substrate as a template by electrophoretic deposition (EPD). Nickel oxide film was deposited on the PS-coated SS substrate. After removal of PS in toluene, the surface of the electrode becomes macroporous structure. Surface morphology of the deposited NiO electrode with addition of surfactant is platelet-like shape observed by SEM. And the morphology of the deposited NiO electrode with PS template is highly macroporous. Besides, when smaller current or potential is applied, the pores of electrodes are larger. While larger current or potential is applied, the pores of electrodes are smaller. After GA-XRD analysis, there is no change in crystal structure by adding the surfactant during deposition. The synthesized nickel hydroxide (Ni(OH)2) is converted into cubic NiO after annealing at 300 ℃ for 1 h. The electrochemical result shows that an optimal addition amount of 1 mM surfactant (CTAB) is obtained in terms of the electrode’s capacitive behavior. Main advantages of adding CTAB in anodic deposition include excellent reversibility, high stability, and long cycle-life. The specific capacitance of the deposited electrodes with surfactant (CTAB) is about 1160 Fg-1, which is much higher than that of deposited by anodic deposition (260Fg-1) reported in literature. Moreover, the macroporous structure of deposited NiO electrode can provide much more surface area for facilitating the electrochemical reaction. Therefore, the specific capacitance of this tailored nickel oxide electrode reaches to 377 Fg-1, which is much better than that reported in literature.
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Lee, Rung-Hau, and 李榮浩. "Nanostructured iron oxide electrodes prepared by electrochemical deposition and their electrochemical properties." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/35996920208085787086.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程系碩士班
96
This research uses electrochemical deposition route to deposit nanostructured iron oxide films for high-performance electrode materials. By tuning the deposition parameters, it is possible to deposit iron oxide film with different surface morphologies. Surface morphology of the nanostructured iron oxide films is investigated by SEM. It is found that the iron oxide film deposited at low-current density (lower than 0.025 mA cm-2) is rod-like morphology of 28~38 nm in diameter; at high-current density (higher than 0.125 mA cm-2) is sheet-like morphology of 20~30 nm in thickness. As-deposited iron oxide film shows aggregation of nanorods. The sheet-like morphology is observed by annealing the film at higher temperatures (100 ℃~500 ℃). When the annealing temperature exceeds over 500 ℃, the sheet-shaped structure transforms into the grain structure. The crystal structure of the deposited iron oxide films is identified by GA-XRD pattern. As-deposited iron oxide film is α-FeO(OH). After annealing at 100 ℃ and 200 ℃, the diffraction peak of γ-FeO(OH) can be observed. The iron hydroxide converts into Fe2O3 structure when the annealing temperature is elevated to 300 ℃. The films deposited at different current densities (0.025~0.25 mA cm-2) and then annealed at various temperatures (100~500 ℃) are investigated in their electrochemical behavior. The aqueous and organic electrolytes are used in the electrochemical investigation, respectively. In aqueous system (1 M Li2SO4), an optimum electrochemical property is obtained by depositing the film at 0.125 mA cm-2 and annealing at 300 ℃; its specific capacitance reaches 145.1 F g-1 at a scan rate of 5 mVs-1. On the other hand, when the organic electrolyte (1 M LiClO4) is used in CV scan, there are two distinct reduction and oxidation peaks at 0.85 V vs. Li/Li+. In cycle-life stability test, an optimum electrochemical performance is obtained by depositing the film at 0.125 mA cm-2 and annealing at 500 ℃. Charging and discharging currents are set at 1000 mA g−1. After 10 cycles, the discharging capacity reaches 1000 mAh g-1.
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Lin, Yi-Chih, and 林義智. "The study of electrochemical capacity properties of Co3O4 thin film by electrochemical deposition." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/29215742079087334491.
Full textAbstract:
碩士大同大學
材料工程學系(所)
98
Abstract The research and development of capacitor’s electrode materials has got a lot of attention recently. This study’s purpose was to prepare cobalt oxides which were applied on capacitor by electroplate and post oxidation methods, and to compare the pseudo-capacitive characteristics. The pseudo-capacitive characteristics analysis including specific capacitance and pseudo-capacitive stability evaluation, were analyzed by circles voltammetry test which was proceeded in 0.02M KOH solution at room temperature with voltage scan range of 0–1V. And the material characteristics of cobalt oxide films test with different cycle number were analyzed torealize the affect factors on the pseudo-capacitive stability. The specific capacitance and specific capacitive stability and pseudo-capacitive stability of cobalt oxide films with added Ag+ were higher then not added Ag+. The specific capacitance value were 968 F/cm3 and 313 F/cm3 respectively, it shows the capacitance value of cobalt oxide films with added Ag+ were better than not added Ag+
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Permanasari, Rina. "Electrochemical deposition of thin film CuGaSe��� for photovoltaics." Thesis, 2004. http://hdl.handle.net/1957/33321.
Full textAbstract:
CuGaSe���/CuInSe��� tandem junction solar cell is currently being pursued to
be a low cost and high efficiency renewable energy source. A reported theoretical
efficiency of 33.9% solar cells has been the motivation to fabricate CuGaSe��� films
in a simple and low cost method. Electrodeposition is a potentially suitable
method to obtain the CuGaSe��� films. A better understanding of the
electrodeposition process is required to optimize the process.
Focusing on the manufacture of CuGaSe��� film, the reaction accompanying
the electrodeposition of CuGaSe��� using rotating disk electrode from cupric
sulfate, selenious acid and gallium chloride solution in sulphate medium were
studied by voltammetry. Cyclic and rotating disk voltammetry in pure and binary
systems were performed in order to understand the complexity of Cu + Ga + Se
systems. Diffusion coefficients of Cu(II) and Se(IV) were determined using
Levich equation to be 6.93x 10������ cm��/s and 9.69x 10������ cm��/s, respectively.
The correlations between supporting electrolytes, flux ratios, working
electrodes and films were investigated experimentally. The deposited films were
characterized by Induced Couple Plasma Spectrometry, X-Ray Diffraction,
Scanning Electron Microscopy and Energy Dispersive X-Ray. CuGaSe��� is formed
via the reaction of CuSe compound reduction and Ga(III) and higher gallium
concentration will favor the formation of CGS film. The incorporation of gallium
is highly depending on the pH (higher is better).
An impinging flow electrochemical reactor was built as an alternative
approach for electrochemical deposition method. Preliminary experiments of
copper and copper selenide electrodeposition were conducted, and the results
were comparable to the rotated disk voltammetry.Graduation date: 2004
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Li, Tsung-Cheng, and 李宗澂. "Investigation of Bath Degradation during Copper Electrochemical Deposition." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/53036196701944719421.
Full textAbstract:
碩士國立交通大學
材料科學與工程系
91
The degradation effects on (PEG, SPS)-containing baths are investigated in this study. The baths are analyzed by three methods: in-situ measured v-t curves of galvanostatic plating, AC-impedance scan, and i-E curve scan. The gap-filling capability for the baths was examined by cross-sectional SEM images. By modifying the mechanisms that were presented in previous literatures, some possible models for the degradation are proposed. In the PEG-containing bath, an evident deterioration of the gap-filling yield and of the surface roughness of the deposited film are observed after ECD aging. Two mechanisms are proposed to explain this degradation: 1) crack of long-chain PEGs, and 2) complexing between PEGs and Cu ions. When some long-chain PEGs crack into shot-chain ones, the remained long-chain PEGs still dominate the value of cell voltage, while slight fluctuation in voltages is attributed to the formation of complexes that results from the continuously cleaved short-chain PEGs. In the (PEG, SPS)-containing bath, a modified mechanism of the behaviors of PEG and SPS are proposed and called “Slow adsorption / desorption mechanism.” As the electroplating proceeds, the variation among v-t curves is divided into two trends: the cell voltages are increasing following by decreasing as more samples plated. Besides, the yield of gap-filling is slightly affected by the variation of the bath, and the superfilling could be maintained even after aging of bath. Three possible mechanisms for the trend of degradation are proposed and will be further discussed in this thesis.
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馮憲平. "Electrochemical deposition Process for ULSI copper interconnect fabrication." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/21701027568809907608.
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Hsu, Ming-Yuan, and 許名沅. "Electrochemical Atomic Layer Deposition of Cu-Ru Film." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/9av6wk.
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碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
102
Preparation of the atomic layer films by an electrochemical atomic layer deposition (ECALD) can solve step coverage issues. This technique can also be used to prepare copper alloy films for semiconductor process. This study presents copper (Cu) films doped with ruthenium (Ru), and hopes the film have a better stability because Ru has good thermal stability and low resistivity. However, preparation of Cu-Ru films by ECALD is rarely studied. This experiment is to analyze and discuss the Cu-Ru alloy films prepared by ECALD. Cu-Ru films were deposited on Au/Ti/glass substrates by ECALD. The process using surface limited redox replacement (SLRR) and underpotential deposition (UPD) to prepare the films. Pb UPD was formed at -0.54 V versus Ag/AgCl, and in Cu solution at open circuit for 1 minute performing redox replacement of Pb UPD by Cu. After that, Ru was deposited in solution at -0.6 V versus Ag/AgCl for 1 minute. The films were deposited by repeating the above processes. After deposition, the samples were annealed at 400℃ in Ar + H2 (95%+5%) atmosphere for 5 minutes. The sheet resistance of the film was measured by four-point probes, film thickness was measured by Alpha-step, crystal structure was analyzed by XRD, surface morphology and cross-sectional images were observed by FE-SEM, atomic concentration was measured by EDS, and atomic binding energy and quantitative analysis were measured by XPS. The results showed that optimal parameters can be obtained at UPD of Cu sol. : -0.1 V, Pb sol.: -0.54 V, and Ru sol. : -0.6 V from the pH 3.5 solution. Cu deposition gradually decreased when increasing Ru deposition because deposition rate of the Pb was slowed down on the Ru film. Au-Cu alloy was formed after annealing at 400℃ for 5 minutes, which resulted in an increase in resistance and densification of the film.
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Singh, Duleshwar. "Electrophoretic Deposition of Graphene on Copper and its Corrosion Behaviour." Thesis, 2016. http://ethesis.nitrkl.ac.in/8226/1/2016-MT-214MM2362-Electrophoretic_Deposition.pdf.
Full textAbstract:
Graphene is a single layer of pure carbon atom that are bonded together in hexagonal or honeycomb lattice structure. The gradual destruction of metal surface by chemical or electrochemical reaction with their environment forms corrosion. The graphene layer has been used as protective thin film on metal surface by electorphoretic depositon (EPD). In the present work, graphene has been synthesized by electrochemical intercalation and exfoliation of pyrolytic graphite sheet by various electrolytes (H2SO4, HNO3, and HCLO4) in varying concentration. The prepared dispersed graphene oxide (GO) solutions were deposited on copper surface with working area of 2cm2 by electrophoretic deposition technique at various (0.1, 0.5, 1 wt %) concentration of graphene. The sodium dodecyl sulfate (SDS) anionic surfactant has been used as binder to increase the thickness of coating. The graphene oxide coatings were used with the aim that it will act as a protective layer for corrosion of Cu substrate. The thickness of the graphene coated thin film was characterized by surface profiler and atomic force microscopy. Morphology of graphene nano sheets and coated graphene was analyzed by FESEM, which has showed clearly microstructure of GNS layer. Topography of graphene coated specimen characterized by AFM and crystal structure, crystalline planes and phases of graphene sheet were characterized by X-ray diffraction. (0 0 2) and (1 0 0) planes showed the graphene sheet has been confirmed by X-ray diffraction. The electrochemical corrosion behavior of graphene coating on Cu in 0.1M NaCl solution has been investigated by potentiodynamic linear sweep voltametry technique. However, the tendency (corrosion potential) is nobler for bare copper substrate. The study needs further experiment and optimization to reach to an affirmative conclusion. The application of GO layer has improved the corrosion resistance property of coated Cu due to better barrierquality of GO layer.
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Tsui, Manus Pui-Hung. "Calcium phosphate coatings on coronary stents by electrochemical deposition." Thesis, 2006. http://hdl.handle.net/2429/18251.
Full textAbstract:
Calcium phosphate ceramic coatings, especially hydroxyapatite (HA), have attracted much attention in the orthopedics and dentistry due to their excellent biocompatibility and bioactivity. Among the different methods of calcium phosphate coatings processing, electrochemical deposition (ECD) is a relatively low cost and flexible process technology. In this study, electrochemical deposition was used to deposit uniform calcium phosphate coatings on 316L stainless steel coronary stents. The influence of the ECD process parameters (deposition time, current density, electrolyte temperature, pH, and Ca/P ratio) on the resulting deposition morphology was investigated. Scanning electron microscopy (SEM) and X-Ray diffractometry (XRD) were used to analyze the coatings. The results demonstrated that both dicalcium phosphate dihydrate (CaHP0₄·2H₂0, DCPD) and hydroxyapatite (Ca₁₀(P0₄)(OH)₂, HA) were present in the uniform [tilde]0.5 [micro sign]m thick as-deposited coating. However, a post-treatment process, including a O.1N NaOH(aq) phase conversion at 75°C and a 500°C heat treatment produced a pure phase HA coating. The final deposit revealed a highly porous surface morphology which could be useful for drug encapsulation. With the application of the substrate surface modification and the post-treatment processes, sufficient coating adhesion was achieved as demonstrated by the in-vitro stent deployment tests without visible damage to the coating. Commercial in-vitro 40 million cycles fatigue tests demonstrated that the coatings exhibit good adhesion to the stent substrate, with no coating cracking or delamination. It was confirmed that the ECD-HA coating process for coronary stents is reliable and reproducible.Applied Science, Faculty of
Materials Engineering, Department of
Graduate