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Echendu, Obi Kingsley. "Thin film solar cells using all-electrodeposited ZnS, CdS and CdTe materials". Thesis, Sheffield Hallam University, 2014. http://shura.shu.ac.uk/19597/.
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The urgent global need for affordable alternative and clean energy supply has triggered extensive research on the development of thin-film solar cells since the past few decades. This has necessitated the search for low-cost, scalable and manufacturable thin-film semiconductor deposition techniques which in turn has led to the research on electrodeposition technique as a possible candidate for the deposition of semiconductor materials and the fabrication of thin-film solar cells using these materials. Electronic quality ZnS, CdS, and CdTe thin layers have been successfully electrodeposited from aqueous solutions on glass/fluorine-doped tin oxide (FTO) substrates, using simplified two-electrode system instead of the conventional three-electrode system. This process was also carried out in a normal physical chemistry laboratory instead of the conventional cleanroom that is very expensive to maintain. The electrodeposited materials were characterised for their structural, optical, electrical, morphological and compositional properties using x-ray diffraction, optical absorption, photoelectrochemical cell, current-voltage, scanning electron microscopy and energy dispersive x-ray techniques respectively. The results show that amorphous n-type and p-type ZnS layers were deposited by varying the concentrations of Zn[2+] and S[2-] in the deposition electrolyte. The CdS layers show hexagonal structure with n-type electrical conduction while CdTe layers show cubic structure with n-type electrical conduction, in the cathodic deposition potential range explored. Using CdTe as the main absorber material, fully fabricated solar cell structures of the n-n hetero-junction + large Schottky barrier type were fabricated instead of the conventional p-n junction type structure. Conventional post-deposition CdCl[2] treatment of CdTe rather carried out with a mixture of CdCl[2] and CdF[2], resulted in pronounced improvement of all the device parameters. Characterisation of the fully fabricated solar cells was done using current-voltage and capacitance-voltage techniques. Promising device parameters were obtained for the best devices, with barrier heights greater than (1.00 - 1.13) eV, short-circuit current densities of (20 - 48) mAcm[-2], open-circuit voltages of (500 - 670) mV, fill factors of (0.33 - 0.47) and overall conversion efficiencies of (5.0 - 12.0)%. Remarkably, the two highest efficiency figures of 10.4% and 12.0% came up for solar cells involving ZnS as buffer layer and window layer with the structures, glass/FTO/n-ZnS/n-CdS/n-CdTe/Au and glass/FTO/n-ZnS/n-CdTe/Au, respectively. At present, the reproducibility and consistency of these devices is poor, but these results demonstrate that these devices structures have the potential to achieve efficiency values over 20% when fully optimised.
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Kayishaer, Aihemaiti. "Détection de l’ammoniac par des capteurs résistifs à base de films de polyaniline électrodéposés". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCD037.
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La thèse vise à développer des capteurs résistifs à base de polyaniline électrosynthétisée pour détecter l’ammoniac à faible concentration (ppb). La polyaniline est un polymère conducteur choisi pour sa conductivité électrique élevée, sa flexibilité et sa stabilité thermique. L’influence de la nature de l’acide, la présence de surfactant et l’utilisation d’aniline fluorée lors de l’électropolymérisation a été étudiée. Ainsi, la synthèse et l’optimisation du film polymère ont été réalisées par électrochimie accompagnées d’une étude complète de sa morphologie, de sa rugosité et de ses propriétés physico-chimiques. Puis, l’impact de la formulation sur la réponse à l’ammoniac a été caractérisé. L’étude des performances métrologiques (réversibilité, répétabilité, sensibilité, reproductibilité, limite de détection, influence de l’humidité et sélectivité) a été menée dans des conditions contrôlées de température et d’humidité relative. La réponse des capteurs s’est avérée être influencée par la nature des contre-ions présents dans le film polymère. Ainsi les films de polyaniline/acide camphorsulfonique permettent d’obtenir des films très reproductibles, réversibles, stables à l’humidité et sensibles avec une limite de détection de 4 ppb. L’ajout de surfactant permet d’offrir une meilleure sensibilité. L’ajout d’aniline fluorée permet également d’améliorer les performances des capteurs notamment en limitant l’influence de l’humiditéThe thesis aims to develop electrosynthesized polyaniline-based resistive sensors to detect ammonia at low concentrations (ppb). Polyaniline is a conductive polymer chosen for its high electrical conductivity, flexibility and thermal stability. The influence of the nature of the acid, the presence of surfactant and the use of fluorinated aniline during electropolymerization was studied. Thus, the synthesis and optimization of the polymer film were carried out by electrochemistry accompanied by a complete study of its morphology, roughness and physicochemical properties. Then, the impact of the formulation on the response to ammonia was characterized. The study of metrological performances (reversibility, repeatability, sensitivity, reproducibility, detection limit, influence of humidity and selectivity) was carried out under controlled conditions of temperature and relative humidity. The response of the sensors was found to be influenced by the nature of the counterions present in the polymer film. Thus, polyaniline/camphorsulfonic acid films make it possible to obtain very reproducible, reversible, humidity-stable and sensitive films with a detection limit of 4 ppb. The addition of surfactant provides better sensitivity. The addition of fluorinated aniline also improves the performance of the sensors, in particular by limiting the influence of humidity
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Campbell-Rance, Debbie. "Electrodeposited Silica Thin Films". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2123.
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Sol-gel derived silica thin film synthesis has gained prominence because of the mild processing conditions and widespread understanding of the chemistry of the process. Traditionally, silicate films are prepared by spin- and dip-coating but these materials lack the desired porosity for sensing, separations and catalysis applications. Electrochemical deposition was proposed to improve the porosity of silicate films. The main aims of this work were threefold. First we wanted to elucidate what parameters influenced film formation during electrodeposition. Then we wanted to understand how these parameters affected the morphology of the materials prepared. These films were characterized by profilometry, AFM, and SEM-EDX. Films electrodeposited via cathodic potentials are particle-like, thicker and rougher than spin-coated films. The final goal was to pattern a substrate with silica using photolithography, sol-gel process and electrodeposition. Successful patterning was hindered by the deposition of silica on glass, especially when the gap between ITO bands was smaller than the diffusion layer thickness of the electroactive species.
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Varea, Espelt Aïda. "Multifunctional Electrodeposited Nanocrystalline Cu-Ni Films". Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/117274.
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Aquesta Tesi engloba la fabricació mitjançant electrodeposició de capes nanocristal·lines de Cu-Ni en tot el rang de composicions, així com la seva caracterització morfològica (microscòpia electrònica de rastreig i de forces atòmiques), microestructural (difracció de raigs X i microscòpia electrònica de transmissió), mecànica (nanoindentació), magnètica (emprant els magnetòmetres d’efecte Kerr magneto-òptic i superconducting quantum interference device – SQUID-), de resistència a la corrosió (mètode de polarització potenciodinàmica), així com la seva estabilitat tèrmica. El procés d’electrodeposició s’ha realitzat en corrent continu en una cel·la convencional de tres elèctrodes. Els banys utilitzats contenen el mateix tipus de sals metàl·liques (sulfats de Cu i Ni) i additius (citrat, dodecilsulfat de sodi i sacarina), però s’ha variat la relació de concentracions [Cu(II)]/[Ni(II)] per tal d’obtenir capes en tot el rang de composicions (Cu1-xNix). Convé destacar l’important paper que fa la sacarina com a agent refinador de gra, ja que la seva presència en el bany permet obtenir capes llises i nanocristal·lines (mida de cristall ~30 nm) amb propietats mecàniques notablement superiors a capes de composició anàloga amb mides de cristall més grans (~400 nm). Per a tots els banys, un augment en el valor absolut de la densitat de corrent comporta un augment del sobrepotencial i, de retruc, un increment del contingut de Ni en els dipòsits. D’aquesta manera, dins de la sèrie de capes nanocristal·lines fabricades, s’observa que la duresa, la resistència al desgast i a la deformació plàstica i la recuperació elàstica milloren en augmentar el contingut en Ni de l’aliatge. S’han assolit valors de duresa de H = 8.2 GPa en capes amb composició Cu0.13Ni0.87, que són força elevats si es comparen amb els valors de duresa que poden trobar-se a la literatura per a capes de naturalesa similar. Tot i així la presència de Cu també pot ésser beneficiosa per a certes aplicacions on s’hagi de sotmetre el material a temperatures elevades, ja que la seva presència contribueix a augmentar l’estabilitat tèrmica de l’aliatge bo i desplaçant l’inici del creixement de gra i, de retruc, el deteriorament de les propietats mecàniques, cap a temperatures de recuit superiors (p.e. T = 575 K per a Cu0.44Ni0.56) en comparació amb aquelles capes amb continguts més baixos de Cu (p.e. T = 525 K per a Cu0.12Ni0.88 i T = 425 K per a Ni pur). Pel que fa a les propietats magnètiques s’ha observat comportament ferromagnètic modulable en capes amb un contingut de Ni superior al 70 at% i s’han estudiat els canvis en els cicles d’histèresi magnètica amb la temperatura de recuit. Quant a la resistència a la corrosió en medi clorur, aquesta augmenta en incrementar el contingut de Ni dels dipòsits. També s’observa que el procés de nanoestructuració no deteriora de forma significativa la resistència a la corrosió del material. Així doncs queda demostrat que, gràcies a l’elevat grau de modulació que s’aconsegueix en les propietats mecàniques i magnètiques, el Cu-Ni és un bon candidat per a la seva implementació en sistemes electromecànics tant a escala micromètrica com nanomètrica. I per aquest mateix motiu, el treball de Tesi finalitza amb la presentació dels resultats derivats de la miniaturització d’aquest aliatge utilitzant el mateix concepte sintètic, de manera que es demostra la fabricació de matrius ordenades de nanocolumnes de diàmetres compresos entre 100 nm i 200 nm així com la seva composició i caracterització magnètica.This Thesis dissertation encompasses the fabrication of nanocrystalline Cu-Ni films in all range of compositions by means of electrodeposition and their morphological (using scanning electron and atomic force microscopies), microstructural (by X-ray diffraction and transmission electron microscopy), mechanical (by nanoindentation) and magnetic (using magneto-optical Kerr effect and superconductor quantum interferometer device –SQUID- magnetometers) characterization, as well as their corrosion resistance (by potentiodynamic polarization method) and thermal stability. The electrodeposition process has been carried out by direct current in a conventional three-electrode cell configuration. The baths used throughout the work contain the same metallic salts (Cu and Ni sulphates) and additives (citrate, sodium dodecylsulphate and saccharine), but the [Cu(II)]/Ni(II)] concentration ratio in solution has been changed to obtain Cu-Ni films in all range of compositions (Cu1-xNix). Saccharine exerts a key role as a grain-refining agent since its addition to the bath leads to smooth, nanocrystalline films (crystallite size ~30 nm) with markedly improved mechanical performance compared to films with similar composition but larger crystallite sizes (~400 nm). For all the baths, an increase of the absolute value of the current density causes an increase in the overpotential which, in turns, yields to the deposits with larger Ni contents. Within the fabricated nanocrystalline films series, larger hardness, improved wear resistance and resistance to plastic deformation and larger elastic recovery are observed as the Ni content in the alloy increases. Hardness values around 8.2 GPa have been achieved for Cu0.13Ni0.87 films, which are larger than those found in the literature for films of similar nature. Even so, the presence of Cu can be beneficial for certain applications where the material has to operate at high temperatures. Namely, the presence of Cu increases the thermal stability by delaying grain growth toward higher annealing temperatures (T = 575 K for Cu0.44Ni0.56) as compared to films with lower Cu contents (T = 525 K for Cu0.12Ni0.88 and T = 425 K for pure Ni). Accordingly, a delay in the deterioration of the mechanical properties is seen. Regarding magnetic behaviour, tuneable ferromagnetic behaviour for Ni contents beyond 70 at% has been found and the changes in the magnetic hysteresis loops with the annealing temperature have been explored. Concerning the corrosion resistance in chloride environments, it improves as the Ni content increases in the deposits. It is also shown that the nanostructuring process does not significantly worsen the corrosion resistance of the material. It is thus demonstrated that, owing to their tuneable mechanical and magnetic properties, Cu-Ni alloys are good candidates for their implementation in electromechanical systems both at micro- and nanoscales. For this reason, this Thesis dissertation ends up with the presentation of the results about the miniaturization of this alloy using the same synthetic concept. In this sense, the fabrication of arrays of ordered nanopillars of 100 and 200 nm in diameter is demonstrated and their composition and magnetic properties are disclosed.
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Lafouresse, Manon. "Kinetic roughening and composition of electrodeposited films". Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443266.
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Qiu, C. X. (Xing Xing). "Investigation of electrodeposited CuInSe2 films for photovoltaic cells". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39267.
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Uniform polycrysalline p-type CuInSe$ sb2$ films, thicknesses ranging from 1 to 4 $ mu$m, were deposited by a stable electrodeposition process developed in our laboratory. A (112) preferred orientation was found for the films. Vacuum annealing experiment results showed an improvement in the crystalline quality of the films after the annealing. The metal ratio of the films was not altered significantly by the annealing process. Al/CuInSe$ sb2$ Schottky junctions fabricated on p-type CuInSe$ sb2$ films showed that the current transport mechanism in the intermediate voltage region was governed by a recombination component. A dispersion effect of the capacitance-voltage curves with frequency, observed on the Schottky junctions suggested the presence of either enhanced interface states or deep levels in the depletion region. Solar cells of CdS/CuInSe$ sb2$ were fabricated by vacuum evaporating low resistivity n-type CdS layers on the electrodeposited p-type CuInSe$ sb2$ films. The highest AM1 active area conversion efficiency, for the 0.9 cm$ sp2$ cells, was 5.2% after an air heat treatment at 200$ sp circ$C. The efficiency value was increased to 5.6% in small area devices fabricated using a similar procedure. The air heat treatment was found to reduce the apparent carrier concentration in the CuInSe$ sb2$ films. Current-voltage (I-V) characteristics of the cells showed a definite relationship between the short circuit current and the indium to copper ratio in the CuInSe$ sb2$ films. Temperature dependent I-V curves revealed a dominant recombination current component for the heterojunction cells. The value of barrier height for a cell was estimated to be 0.64 eV. It was found that the differential capacitance values depended on measurement frequencies, resulting in frequency-dependent voltage intercepts. The C$ sp{-2}$-V curves were also observed to shift to more negative voltages under illumination. Interface states were believed to be responsible for all these effec
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Qiu, Chunong. "Development of photovoltaic cells on electrodeposited CuInSe2 films". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39982.
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Using polycrystalline thin films of CuInSe$ sb2$ (thickness 1.5 $ mu$m) prepared by an electrodeposition method, photovoltaic cells of the form ZnO/CdS/CuInSe$ sb2$ have been fabricated and studied. Before the cell fabrication, properties of the electrodeposited CuInSe$ sb2$ were first studied. Conditions for the preparation of high resistivity CdS thin films (thickness 360 A) by a chemical bath deposition method were then established. This was achieved by varying the deposition temperature and amount of NH$ sb4$OH in the solution. It was observed that the quality of CdS films deposited at a temperature of 60$ sp circ$C and an NH$ sb4$OH concentration of 0.48 M was the best. Thermal stability of low resistivity, In- or Ar-doped, rf-sputtered ZnO thin films (thickness 1$ mu$m) was also studied. This was done by heat treating the ZnO films in air, O$ sb2$ and N$ sb2$ at temperature in a range from 200 to 350$ sp circ$C. It was observed that the amount of increase of resistivity at a given temperature decreased as the doping concentration was increased from 0.5 to 5.3 wt.%. For the films containing 2 wt.% In or Al, the resistivity increased as the treating temperature was increased from 200 to 350$ sp circ$C. For the samples treated at 200$ sp circ$C, the increase in resistivity was about 1 order of magnitude.The high resistivity CdS and low resistivity ZnO thin films were then deposited on electrodeposited CuInSe$ sb2$ to fabricate cells of the form ZnO/CdS(high $ rho$)/CuInSe$ sb2$. For comparison, cells of CdS(low $ rho$)/CdS(high $ rho$)/CuInSe$ sb2$ were also fabricated by evaporation of low resistivity CdS. The CuInSe$ sb2$ films used were treated either in vacuum or Ar. For those treated in vacuum, very poor properties were observed. The properties improved after a post fabrication heat treatment in air, however, the efficiency of these cells was below 2%. The low conversion efficiency was due to the low open circuit voltage. From capacitance-voltage measurements, this was found to be due to a high acceptor concentration on the surface of the vacuum treated CuInSe$ sb2$ films (10$ sp{17}$ cm$ sp{-3}$). For the cells fabricated on the CuInSe$ sb2$ films treated in Ar, photovoltaic effects were present before the air heat treatment. An efficiency of 6.8% was obtained for one of the best cells, sample J8-4 (with low resistivity CdS window). For cells with ZnO window, a conversion efficiency of 6.3% was obtained (cell O51). For these cells, the acceptor concentration in CuInSe$ sb2$ was 10$ sp{16}$ cm$ sp{-3}$, which was one order of magnitude lower than that of CuInSe$ sb2$ films treated in vacuum.
The diffusion length of minority carriers (electrons) in the electrodeposited, p-type CuInSe$ sb2$ was first measured using the photocurrent and capacitance methods. For the vacuum treated CuInSe$ sb2$ films, the electron diffusion length was small (less than 0.1 $ mu$m). For those treated in Ar, values of the electron diffusion length were about 0.5 $ mu$m. These values are close to those reported for evaporated CuInSe$ sb2$ thin films.
Some of the fabricated cells were also studied using an electron beam induced current (EBIC) method. From the EBIC experiments, the effective diffusion lengths of electrons with values greater than 1 $ mu$m were obtained. Considering the surface recombination effect, the electron diffusion length of the electrodeposited CuInSe$ sb2$ was finally found to be 2.4 $ mu$m. This large electron diffusion length was consistent with the high short circuit current density observed in I-V measurements of the electrodeposited CuInSe$ sb2$ cells.
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Teng, Chien-Lung. "Investigation of Electrodeposited Magnetite Films : Formation and Characterization". Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/4260.
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Magnetite (Fe3O4) is of both scientific and technological interest because of its fascinating magnetic properties. It has a high Curie temperature of 860 K and a theoretical 100% spin polarization at the Fermi level. There are a variety of deposition techniques to form thin films of magnetite, such as molecular beam epitaxy (MBE), pulsed laser deposition (PLD), iron oxidation, sputtering and so on. In comparison with other deposition methods mentioned above, electrodeposition has a key advantage of relatively low processing temperature. The intention of this work was to investigate magnetite (Fe3O4) thin films grown via an electrochemical route by using various kinds of characterization techniques, especially on morphology, chemical composition, structure and magnetic properties. Fe3O4 thin films were obtained by using a galvanostatic or potentiostatic deposition from simple aqueous solutions of ferrous salts. Iron oxide thin films have been grown at different current densities and temperatures onto polycrystalline copper substrates. XRD results indicate that Fe3O4 is formed at 90 oC at an applied current density of 0.05 mA·cm-2. Lower growth temperatures can cause the formation of another phase, a-FeOOH at a certain concentration of Fe2+ and pH buffer. Time-dependent growth of the iron oxides exhibits nucleation and coalescence. In order to obtain uniform Fe3O4 film surface, longer deposition times are needed. The influence of applied potential on the characteristics of the deposited iron oxide was examined. The formation of Fe3O4 in a low potential regime (< 100 mV) vs. gold reference electrode while iron oxyhydroxides such as goethite (a-FeOOH) and lepidocrocite (?-FeOOH) are favoured for E > 100 mV. The magnetic properties of the films were found to be strongly dependent on the deposition potential. The multi-layer structure of Fe3O4/a-FeOOH/Fe3O4 onto NiO/Ni substrates has been demonstrated via successive deposition. A TEM cross-section image shows a-FeOOH is coherently formed between two ferromagnetic layers. ADF-STEM micrographs show that Fe3O4 has a columnar structure and has less composition variation compared to that grown onto a polycrystalline copper substrate. Synchrotron techniques, i.e. x-ray absorption near edge structure (XANES) and x-ray magnetic circular dichroism (XMCD), were performed to examine the iron oxide film. Fe K-edge x-ray absorption spectra demonstrate that the films grown at low potential regime (< 100 mV) have a comparable valency state with the standard Fe3O4 sample. The identification of the iron oxide was further confirmed by using XMCD technique. The calculation of the asymmetry ratio suggests that the total magnetic moment increased with decreasing applied potential. In addition, vibrating sample magnetometer (VSM) data show that the magnetic response is somewhat slower for the iron oxide grown at higher potential regime. A change of pH in the electrolyte does not change the lattice constant and film morphology or texture but does affect particle sizes in Fe3O4 thin films. This decrease with the pH is due to the reaction of FeOH+ ions with molecular oxygen in electrolyte.
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Campbell, S. A. "Structural and photoelectrochemical studies of electrodeposited lead dioxide films". Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378266.
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McGregor, Stephen Mark. "Solar cells based on electrodeposited Cds and CdTe films". Thesis, Sheffield Hallam University, 1999. http://shura.shu.ac.uk/20043/.
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The aim of this study was to understand the properties of glass/TCO/CdS/CdTe/metal solar cells, the CdS and CdTe being grown by aqueous electrodeposition. Deposited films and completed cells were characterised using electrical, structural and optical techniques. This report describes the production of well-formed polycrystalline CdS and CdTe with well defined XRD peaks and band gap. Experiments were performed to investigate the pre-conditioning of the CdTe bath on the overall cell performance. Pre-conditioning the CdTe deposition bath was found to improve the Voc value of the completed devices. It has been known for some time that treating the CdTe layer of a CdS/CdTe solar cell with chlorine brings about significant improvements in the efficiency of these devices. This report presents results on a systematic variation of the chlorine concentration within a CdTe deposition bath. Solar simulated I-V measurements of completed devices clearly show that the addition of CdCl[2] to the CdTe deposition bath significantly improved the efficiency values for the glass/TCO/CdS/CdTe/metal devices. The electrical parameter most significantly affected by the addition of chlorine is the J[sc] value. In terms of the Voc performance of the device, this investigation showed that there was a trend of improving Voc with increasing chlorine concentration. Addition of chlorine also produces improvements in the preferred orientation of CdTe films as measured by XRD. Optical absorption results showed a correlation that the minima of the band gap vs. chlorine concentration graph for annealed samples matches up with the maximum in the efficiency and J[sc] graphs. To investigate whether this phenomenon was specific to chlorine or was displayed by other elements, similar experiments were performed with no chlorine inclusion but varying the indium concentration in the deposition bath. Solar simulated I-V measurements of completed devices clearly show that the addition of In[2](SO[4])[3] to the CdTe deposition bath significantly reduced the efficiency values for the glass/TCO/CdS/CdTe/metal devices. The electrical parameter most significantly affected by the addition of indium is the J[sc] value. The addition of indium also had a detrimental effect on the preferred orientation measured by XRD.
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Wood, Matthew Aaron Saunders. "Roughening of electrodeposited copper films: mass transport and additive effects". Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492459.
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The surface roughness growth of electrodeposited copper films was studied with a particular focus on mass transport effects and the influence of millimolar quantities of halide additives on the surface roughness scaling, the surface morphology and microstructure.
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Scragg, Jonathan James. "Studies of Cu2ZnSnS4 films prepared by sulfurisation of electrodeposited precursors". Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527514.
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Cu2ZnSnS4 (CZTS), being related to the highly successful Cu(In,Ga)(S,Se)2, and CuInS2 materials, is a promising candidate for thin film photovoltaic devices. It has the advantage that it contains no rare or expensive elements, and therefore has cost-reduction potential for commercial systems. A two-stage process for fabrication of CZTS films is presented, which consists of sequential electrodeposition of Cu, Sn and Zn layers followed by a heat treatment in the presence of S vapour (‘sulfurisation’). Electrodeposition conditions are developed to give uniform Cu|Sn|Cu|Zn precursors of controlled morphology and composition, by the use of a rotating disc electrode system. Precursors are converted to CZTS by sulfurisation in the presence of elemental S, using a rapid thermal processing system (RTP). The sulfurisation reaction is studied by XRD and Raman spectroscopy as a function of temperature and at short time intervals, and a sequence of reactions is derived for the formation of CZTS. It is shown that the sulfurisation reaction occurs within minutes above 500°C. A model is presented for film formation when rapid heating rates are employed. The effects of sulfurisation time, background pressure and precursor composition on the morphological and structural properties of the CZTS films are investigated. Observations of grain size changes and compositional modification are made and explained in terms of the likely secondary phases present. The opto-electronic properties of the CZTS films are measured using a photoelectrochemical technique. Changes in the external quantum efficiency and band gap are studied as a function of sulfurisation parameters and precursor composition. After crystallisation of the CZTS phase during sulfurisation, the photocurrent obtained from the films continued to rise upon heating in the absence of S, which is explained by changes in acceptor concentration. Large shifts in the band gap are seen, and some proposals are made to explain the behaviour. The observations are discussed in the context of the particular compositions and sulfurisation conditions routinely used in the CZTS literature, and recommendations are made for further work.
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Alshwawreh, Nidal Khalaf. "Microstructure evolution in electrodeposited copper thin films for advanced microelectronic applications". Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42173.
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Copper interconnects in advanced integrated circuits are manufactured by processes that include electrodeposition, chemical mechanical polishing and annealing. The as-deposited copper is nano-crystalline and undergoes a microstructure evolution at room temperature (self-annealing) or during an annealing step. During this process, significant changes in resistivity and grain size are observed. In this work, the microstructure evolution in 0.5-3 μm-thick electrodeposited copper thin films was studied. Resistivity measurements were used to quantify the role of deposition conditions on the microstructure evolution rate. In-situ electron backscatter diffraction (EBSD) was employed to observe self-annealing at the film surface. The resistivity-microstructure correlation during self-annealing was examined. A phenomenological model using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) approach was developed to describe recrystallization during isothermal and continuous annealing treatments. The microstructure evolution in copper-silver alloys and films produced by variable deposition rates was investigated. Phase-field model was applied to simulate self-annealing and the effect of deposition current density.
The results show that the drop in resistivity during self-annealing is accompanied by significant changes of the microstructure at the film surface. Different criteria were developed to assess self-annealing rate from EBSD maps including grain size, image quality and local orientation spread. Adopting a grain size threshold, it was found that there is a reasonable correlation between resistivity and microstructure during self-annealing. The recrystallization in copper thin films appears to be thermally activated with an activation energy of 0.89-0.93 eV. Adopting the principle of additivity, it was found that the recrystallization rate during continuous annealing can be described by the JMAK model using the isothermal resistivity profiles. A method was proposed to accelerate recrystallization based on a capping layer deposition. No recrystallization was observed when silver was co-deposited with copper in the absence of chloride (even when annealed at 100 °C for 5 hours). Phase-field model was able to describe self-annealing and the effect of deposition current density. The results in this thesis are of significance to the microelectronic industry where recrystallization is a crucial step in the fabrication of copper interconnects for the high performance integrated circuits.
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Dreyer, Erin C. "Characterization of electrodeposited chitosan films by atomic force microscopy and raman spectroscopy". College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3596.
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Thesis (M.S.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept. of Material Science and Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Novogradecz, Katharine M. "Characterization of electrodeposited NiFeCu & Cu single & multilayer films on Si(111)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0020/MQ28630.pdf.
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Weerasinghe, Ajith R. "Solar cells based on electrodeposited thin films of ZnS, CdS, CdSSe and CdTe". Thesis, Sheffield Hallam University, 2013. http://shura.shu.ac.uk/20512/.
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The motivations of this research were to produce increased efficiency and low-cost solar cells. The production efficiency of Si solar cells has almost reached their theoretical limit, and reducing the manufacturing cost of Si solar cells is difficult to achieve due to the high-energy usage in material purifying and processing stages. Due to the low usage of materials and input energy, thin film solar cells have the potential to reduce the costs. CdS/CdTe thin film solar cells are already the cheapest on $/W basis. The cost of CdTe solar cells can be further reduced if all the semiconducting layers are fabricated using the electrodeposition (ED) method. ED method is scalable, low in the usage of energy and raw materials. These benefits lead to the cost effective production of semiconductors. The conventional method of fabricating CdS layers produces Cd containing waste solutions routinely, which adds to the cost of solar cells. ZnS, CdS and CdS(i-X)Sex buffer and window layers and CdTe absorber layers have been successfully electrodeposited and explored under this research investigation. These layers were fully characterised using complementary techniques to evaluate the material properties. Photoelectrochemical (PEC) studies, optical absorption, X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, atomic force microscopy (AFM) and Raman spectroscopy were utilised to evaluate the material properties of these solid thin film layers. ZnS and CdS thin film layers were electrodeposited from Na-free chemical precursors to avoid the group I element (Na) to reduce deterioration of CdTe devices. Deposition parameters such as, growth substrates, temperature, pH, growth cathodic voltage, stirring rate, time and chemical concentrations were identified to fabricate the above semiconductors. To further optimise these layers, a heat treatment process specific to the material was developed. In addition, the deposition parameters of CdTe layers were further optimised. This research programme has demonstrated that electrodeposited ZnS, CdS and CdTe thin film layers have material characteristics comparable with those of the materials reported in the literature and can be used in thin film solar cell devices. Furthermore, the electrolytes were used for up to two years, reducing the wastage even further, in comparison to other fabrication methods, such as chemical bath deposition. Several large-area semiconducting layers were successfully fabricated to test the scalability of the method. Nano-rods perpendicular to the glass/FTO surface with gaps among grains in CdS layers were observed. In order to reduce the possible pinholes due the gaps, a deposition of a semiconducting layer to cover completely the substrate was investigated. CdS(i-X)Sex layers were investigated to produce a layer-by-layer deposition of the material. However it was observed the surface morphology of CdS(j.X)Sex is a function of the growth parameters which produced nano-wires, nano-tubes and nano-sheets. This is the first recording of this effect for a low temperature deposition method, minimising the cost of producing this highly photosensitive material for use in various nano technology applications.The basic structure experimented was glass/conducting-glass/buffer layer/window material/absorber material/metal. By utilising all the semiconducting layers developed, several solar cell device structures were designed, fabricated and tested. This included a novel all-electrodeposited multi-layer graded bandgap device, to enhance the absorption of solar photons. The device efficiencies varied from batch to batch, and efficiencies in the range (3-7)% were observed. The variations in chemical concentrations, surface states and the presence of pin-hole defects in CdS were the main reasons for the range of efficiencies obtained. In the future work section, ways to avoid these variations and to increase efficiencies are identified and presented.
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Zhou, Quanguo. "Fabrication and characterization of electrodeposited MiFeMo magnetic thin films and organic metal-base transistor". Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520182.
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Guerin, Samuel. "Planar pellistors : an application of electrodeposited mesoporous palladium films for the detection of combustible gases". Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310482.
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Heiderich, Sonja [Verfasser] y Kornelius [Akademischer Betreuer] Nielsch. "Investigation on Electrodeposited Bismuth and Bismuth Antimony Thin Films and Nanowires / Sonja Heiderich. Betreuer: Kornelius Nielsch". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1038789982/34.
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Khatri, Manvendra Singh. "Structure, microstructure and magnetic properties of electrodeposited Co and Co-Pt in different nanoscale geometries". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-39371.
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Thin films and nanowires of Co-Pt have been prepared by means of electrodeposition. Composition, structure, microstructure and magnetic properties have been intensively studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry and correlated to the deposition parameters such as electrolyte composition, deposition current and/or potential. Co rich Co-Pt films have been deposited at various current densities. A nearly constant composition of Co70Pt30 was achieved for current densities between 18 and 32 mA/cm². Detailed texture measurements confirmed an increasing fraction of the hexagonal phase with its c-axis aligned perpendicular to the film plane with increasing current density. Accordingly, magnetic properties are strongly affected by the magnetocrystalline anisotropy of the hexagonal phase that competes with the shape anisotropy of the thin film geometry. Co-Pt nanowires have been prepared within alumina templates at different deposition potentials between -0.6 and -0.9VSCE changing the composition from nearly pure Pt to Co. The composition Co80Pt20 was observed at a deposition potential of -0.7VSCE. Co-Pt nanowires are nanocrystalline in the as-deposited state. Magnetic measurements reveal changing fcc and hcp phase fractions within the wires as the effective anisotropy significantly differs from the expected shape anisotropy for nanowires with high aspect ratio. This change in effective anisotropy is attributed to the preferential alignment of the c-axis of hcp Co-Pt phase perpendicular to the nanowires axis. A promising alternative with much smaller feature sizes is the diblock copolymer template. Electrodeposition of Co and Co-Pt into these templates has been carried out. Inhomogeneities in the template thickness as well as a certain substrate roughness have been identified to be the reasons for inhomogeneous template filling. Thus magnetic properties are dominated by large deposits found on top of the template. Additionally, rolled-up tubes of several nm thick Au/Co/Au films have been characterized magnetically. Temperature dependent measurements show an exchange bias behaviour that is explained in terms of induced stresses during cooling. Changes of magnetic properties in the investigated samples are finally discussed in terms of competing effects of different magnetic anisotropies in various geometriesCo-Pt Dünnschichten und Nanodrähte wurden mittels elektrochemischer Abscheidung hergestellt. Zusammensetzung, Struktur, Mikrostruktur und magnetische Eigenschaften wurden intensiv mit Röntgenbeugung, Rasterelektronenmikroskopie und Magnetometrie untersucht und mit den Depositionsparametern wie Elektrolytzusammensetzung, Abscheidestrom und/oder-potential korreliert. Co reiche Co-Pt-Filme wurden mit verschiedenen Stromdichten hergestellt. Eine nahezu konstante Zusammensetzung im Bereich Co70Pt30 wurde für Stromdichten zwischen 18 und 32 mA/cm² erreicht. Detaillierte Texturmessungen bestätigen einen zunehmenden Anteil an hexagonaler Phase mit senkrecht zur Filmebene ausgerichteter c-Achse mit zunehmender Stromdichte. Dementsprechend werden die magnetischen Eigenschaften stark von der magnetokristallinen Anisotropie der hexagonalen Phase beeinflusst, die mit der Formanisotropie der Dünnschicht-Geometrie konkurriert. Co-Pt-Nanodrähte wurden in nanoporöse Aluminiumoxidmembranen bei verschiedenen Potentialen zwischen -0,6 und -0.9 VSCE abgeschieden, wobei sich die Zusammensetzung von nahezu reinem Pt zu Co verändert. Die Zusammensetzung Co80Pt20 wurde bei einem Abscheidepotential von -0.7 VSCE erhalten. Die so hergestellten Co-Pt Nanodrähte sind nanokistallin. Magnetische Messungen weisen jedoch auf veränderte Phasenanteile der fcc und hcp Phase innerhalb der Drähte hin, da die effektive Anisotropie erheblich von der für Nanodrähte mit hohem Aspektverhältnis erwarteten Formanisotropie abweicht. Diese Änderung der effektiven Anisotropie ist auf die bevorzugte Ausrichtung der hexagonalen c-Achse des Co-Pt senkrecht zur Drahtachse zurückzuführen. Vielversprechende Template mit deutlich kleineren Dimensionen sind Diblockcopolymertemplate. Es wurden Versuche zur Abscheidung von Co und Co-Pt in diese Template durchgeführt. Als Gründe für die inhomogene Templatfüllung wurden Inhomogenitäten in der Schichtdicke sowie eine gewisse Rauhigkeit der Substrate identifiziert. Aufgrund der ungleichmäßigen Fülleg werden die magnetischen Eigenschaften durch große, halbkugelförmige Abscheidunge auf der Oberfläche des Templates bestimmt. Darüber hinaus wurden aus wenige nm dicken Au/Co/Au Filmen hergestellte Mikroröhren magnetisch charakterisiert. Temperaturabhängige Messungen zeigen ein Exchange Bias Verhalten, das durch beim Abkühlen induzierte Spannungen erklärt wird. Unterschiede im magnetischen Verhalten der untersuchten Proben werden abschließend im Hinblick auf die verschiedenen konkurrierenden magnetischen Anisotropien in verschiedenen Geometrien diskutiert
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Schumacher, Christian [Verfasser] y Kornelius [Akademischer Betreuer] Nielsch. "Pulsed Electrodeposited p- and n-Doped Chalcogenide Semiconductors for Thermoelectric Applications: From Films to Nanowires / Christian Schumacher. Betreuer: Kornelius Nielsch". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2012. http://d-nb.info/1023947366/34.
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Chan, Raymond. "Interfacial Electrochemistry and Surface Characterization: Hydrogen Terminated Silicon, Electrolessly Deposited Palladium & Platinum on Pyrolyzed Photoresist Films and Electrodeposited Copper on Iridium". Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4432/.
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Hydrogen terminated silicon surfaces play an important role in the integrated circuit (IC) industry. Ultra-pure water is extensively used for the cleaning and surface preparation of silicon surfaces. This work studies the effects of ultra-pure water on hydrogen passivated silicon surfaces in a short time frame of 120 minutes using fourier transform infrared spectroscopy – attenuated total reflection techniques. Varying conditions of ultra-pure water are used. This includes dissolved oxygen poor media after nitrogen bubbling and equilibration under nitrogen atmosphere, as well as metal contaminated solutions. Both microscopically rough and ideal monohydride terminated surfaces are examined. Hydrogen terminated silicon is also used as the sensing electrode for a potentiometric sensor for ultra-trace amounts of metal contaminants. Previous studies show the use of this potentiometric electrode sensor in hydrofluoric acid solution. This work is able to shows sensor function in ultra-pure water media without the need for further addition of hydrofluoric acid. This is considered a boon for the sensor due to the hazardous nature of hydrofluoric acid. Thin carbon films can be formed by spin coating photoresist onto silicon substrates and pyrolyzing at 1000 degrees C under reducing conditions. This work also shows that the electroless deposition of palladium and platinum may be accomplished in hydrofluoric acid solutions to attain palladium and platinum nanoparticles on a this film carbon surface for use as an electrode. Catalysis of these substrates is studied using hydrogen evolution in acidic media, cyclic voltammetry, and catalysis of formaldehyde. X-ray diffractometry (XRD) is used to ensure that there is little strain on palladium and platinum particles. Iridium is thought to be a prime candidate for investigation as a new generation copper diffusion barrier for the IC industry. Copper electrodeposition on iridium is studied to address the potential of iridium as a copper diffusion barrier. Copper electrodeposition is studied using a current-transient technique to obtain insight into the nucleation and growth mechanism. Copper on iridum was annealed up to 600 degrees C. X-ray photoelectron spectroscopy and XRD confirm that electrodeposited copper exists in a metallic state. XRD shows that copper exists in the characteristic face-centered cubic (111) form. XRD also confirms the stability of the copper-iridium interface with no new peaks after annealing, which is indicative that no interaction occurs. Scanning electron microscopy, and Scotch ® Tape peel tests confirm the uniformity and strength of copper on iridium even after annealing to 600 degrees C.
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Cabrera-Anaya, Juan Manuel. "Growth of zinc whiskers". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI039/document.
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Les whiskers, filaments métalliques qui poussent sur des surfaces métalliques, sont unproblème très important pour la fiabilité des composants électroniques. Depuis ces dernièresannées, il y a eu un regain d’intérêts industriels dans le domaine de la croissance des whiskers,principalement en raison de la miniaturisation des dispositifs électroniques et des réglementationsenvironnementales interdisant l'utilisation du plomb.Alors que la plupart des recherches concernent les whiskers d'étain, il y a encore peu detravaux sur les whiskers de zinc. Les revêtements d’électrodéposés de zinc sont utilisés commeprotection anticorrosion pour les aciers faiblement alliés dans diverses industries, commel'automobile, l'aéronautique ou l'énergie, ainsi que dans les structures de soutien ou les planchersfaux plafonds dans les centres de données informatiques. Afin d'atténuer, de prévenir et deprédire les défaillances causées par les whiskers de zinc, les mécanismes de sa croissance doiventêtre compris.Grâce à des tests de stockage accéléré et à des observations par microscopie électronique àbalayage (MEB), la cinétique de croissance des whiskers de zinc a été étudiée sur des tôles d'acierau carbone faiblement allié, galvanisé et chromé. Afin de comprendre les mécanismes de lacroissance des whiskers de zinc, la caractérisation quantitative ainsi que les excroissances (densité,volume et vitesse de croissance) ont été reliées aux paramètres suivants: la température, le bainpour l’électrodéposition du zinc, la chromatation, l’épaisseur du substrat d’acier, l’épaisseur durevêtement de zinc ainsi que la contrainte résiduelle.En outre, la microstructure et la cristallographie du revêtement de zinc, des racines deswhiskers ainsi que des whiskers elles-mêmes ont été étudiées par diffraction des électronsrétrodiffusés (EBSD), microscopie électronique à transmission (MET), microanalyse par rayon X(EDX) et le dispositif ASTAR pour l'orientation locale des grains; la préparation des échantillonsa été réalisée à l’aide d’un faisceau d'ions focalisés (FIB). La recristallisation ainsi que lesdislocations dans les whiskers et les excroissances ont été observés; aucun composéintermétallique n’a été observé que ce soit dans les échantillons issus de différents bainsélectrolytes ou encore dans les films / whiskers.Il a été montré que la relaxation de contrainte de compression résiduelle et la croissance deswhiskers sont deux phénomènes différents mais fortement reliés et thermiquement activés.Chacun d'entre eux suit un mécanisme différent; les énergies d'activation apparentes des deuxphénomènes ont été établies, et la diffusion aux joints de grains est proposée comme le principalmécanisme de diffusion pour la croissance des whiskers.Des cinétiques de la croissance des whiskers, à la fois analytique et phénoménologique sontproposées. Une bonne estimation de la croissance des whiskers et de leur vitesse de croissance àdes températures proches des conditions de fonctionnement est obtenue par comparaison avecles données expérimentalesWhiskers, conductive metallic filaments that grow from metallic surfaces, are a very importantissue for reliability of electronic components. Through recent years, there has been a renewedindustrial interest on whisker growth, mainly due to the miniaturization of electronic devices andthe environmental regulations forbidding the use of lead.While most of the research has been focused on tin whiskers, there is still little reference tozinc whiskers. Electroplated zinc coatings are actually used as anticorrosive protection for lowalloy steels in diverse industries such as automotive, aerospace or energy, as well as for supportstructures or raised-floor tiles in computer data centers. In order to mitigate, prevent and predictthe failures caused by the zinc whiskers, the mechanisms of growth must be understood.By accelerated storage tests and Scanning Electron Microscopy (SEM) observation, kinetics ofgrowth of zinc whiskers was studied on low alloy chromed electroplated carbon steel.Quantitative characterization of both whisker and hillocks (density, volume and growth rate) wasrelated with the parameters temperature, electroplating electrolyte, presence of chrome, steelsubstrate thickness, zinc coating thickness and residual stress, in order to understand themechanisms of growth.Additionally, both microstructure and crystallography of zinc coating, whisker roots and actualwhiskers were studied by Electron Backscatter Diffraction (EBSD), Transmission ElectronMicroscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX) and local grain orientationwith ASTAR setup, using Focused Ion Beam (FIB) for samples preparation. Recrystallization aswell as dislocations were observed in both whiskers and hillocks; no intermetallic compoundswere seen in neither electroplated nor whiskers.It is found that compressive residual stress relaxation and whiskers growth are two differentbut strongly interconnected phenomena both thermally activated, an each of them follows adifferent mechanism; apparent activation energies of the two phenomena are calculated, andgrain boundary diffusion is established as the main diffusion mechanism for whiskers growth.Whiskers growth kinetics, both analytical and phenomenological is proposed. Goodestimation of whiskers growth and whiskers growth rate at temperatures close to operationconditions is obtained when compared with experimental data
Whiskers, filamentos metálicos que crecen en superficies metálicas, son un problema muyimportante para la fiabilidad de componentes electrónicos. Durante los últimos años, ha habidoun renovado interés industrial en el crecimiento de whiskers, debido principalmente a laminiaturización de dispositivos electrónicos y a las regulaciones ambientales que prohíben lautilización de plomo.La mayoría de las investigaciones se concentran en los whiskers de estaño y hay todavía pocostrabajos sobre los whiskers de zinc. Los recubrimientos de zinc electrodepositado son utilizadoscomo protección anticorrosión para los aceros de baja aleación en diversas industrias, comoautomotriz, aeronáutica o energética, así como en la estructuras de soporte o tejas de techosfalsos en los centros de datos informáticos. Para atenuar, prevenir y predecir las fallas causadaspor los whiskers de zinc, los mecanismos de crecimiento deben ser comprendidos.Gracias a experimentos de almacenamiento de muestras y a observaciones por microscopíaelectrónica de barrido (SEM), la cinética de crecimiento de whiskers de zinc ha sido estudiada enaceros de baja aleación recubiertos de zinc y cromados. Para comprender los mecanismos decrecimiento de whiskers de zinc, la caracterización cuantitativa de whiskers y de protuberancias(densidad, volumen y velocidad de crecimiento) fue relacionada con los parámetros siguientes:temperatura, electrolito usado en la electrodeposición de zinc, cromado, espesor del substrato deacero, espesor del recubrimiento de zinc al igual que el estrés residual.Adicionalmente, microestructura y cristalografía del recubrimiento de zinc, de raíces dewhiskers así como de los propios whiskers fueron estudiadas por medio de la difracción deelectrones por retrodispersión (EBSD), microscopía electrónica de transmisión (TEM),microanálisis por rayos X (EDX) y el dispositivo ASTAR para la orientación local de granos; lapreparación de muestras fue realizada con la ayuda de un haz de iones localizados (FIB). Larecristalización así como las dislocaciones en whiskers y protuberancias fueron observadas;ningún compuesto intermetálico ha sido observado en los recubrimientos ni en los whiskers.Se determinó que la relajación del estrés residual de compresión y el crecimiento de whiskersson dos fenómenos diferentes pero fuertemente interconectados y térmicamente activados. Cadauno de ellos sigue un mecanismo diferente; las energías de activación aparentes de los dosfenómenos han sido establecidas, y la difusión por bordes de grano es propuesta como elprincipal mecanismo de difusión para el crecimiento de whiskers.Cinéticas de crecimiento de whiskers, a la vez analíticas y fenomenológicas son propuestas.Una buena estimación del crecimiento de whiskers y su velocidad de crecimiento a temperaturascercanas a las condiciones de operación es obtenida por comparación con los datosexperimentales
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吳承哲. "Growth characterization of electrodeposited ZnO thin film on copper thin film". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/68932165056020424540.
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碩士建國科技大學
機械工程系暨製造科技研究所
98
The study uses magnetron sputtering to produce a copper thin film deposited on silicon substrates to provide a copper thin film substrate. Then electrochemical methods are adopted to investigate the properties of ZnO thin films. Aiming to understand the ZnO thin film deposited on copper thin film substrate, the study conducts experiments on various electrochemical parameters of ZnO. ZnO thin films are obtained via electrochemical deposition with controlled parameters such as concentration of electrochemical solution, voltage and temperature. X-ray Diffraction and scanning electron microscope are employed to examine and observe the crystal structure and surface properties of the thin film. The structural advantages and disadvantages of ZnO thin films are determined using Debye-Scherrer formula and texture formula. The findings of the experiment indicate that the presence of the ZnO buffer layer in the sample facilitates the crystal growth of ZnO, and optimal ZnO thin films can be obtained with temperature at 90oC, the concentration of zinc nitrate at 0.02M and with the presence of ZnO buffer layer.
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Yeh, Fei-tao y 葉斐濤. "Synthesis and Characterization of Electrodeposited CuInSe2 Thin Film". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/90332700092650830958.
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碩士國立中山大學
化學系研究所
89
The dominant research subjects are focused on the growth of high quality stoichiometric of CuInSe2 epitaxial films by chemical electrodeposited. For chemical electrodeposited growth, it is possible to obtain the high economical films and to get easier and quicker of the composition and properties by controlling the growth parameters carefully. Under the conditions of fixed copper ion（Cu2+）concentration and excess indium ion（In3+）concentration, we can change selenium（Se4+） concentration to get films. We hope it could be used in the manufacture of solar cell and get high conversion efficiency.
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Lung, Su Chung y 蘇忠龍. "Electrodeposited Molybdenum Oxide Film and Its Electrochromic Properties". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/16677179216997106959.
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Kuan, Lin Chang y 林昌寬. "Electrodeposited nickel oxide film and its electrochromic properties". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/59394419958380359920.
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碩士國立成功大學
化學工程研究所
81
Nickel oxide films were prepared by anodic deposition on both bare ITO glass and gelatin-coated ITO glass electrodes. Electrochromic behaviors were studied with cyclic voltammetry and spectroscopy. The diffusivities of hydrogen atom in the nickel oxide film were obtained with potential step method. The greatest difference of transmittance of nickel oxide film between the coloration state and the bleaching states occurred at wavelength of 540nm. From the experimental results , the nickel oxide film obtained from the electrolyte of pH=8.7 containing 0.005M Ni had the greatest differenceat wavelength of 540nm. The electrodeposited nickel oxide films obtained with a constant potential, with or without agitation, had a linear relationship between gelatin thickness(δ) and transmittance difference(△Ｔ540) between the coloration and the bleaching states: with agitation △Ｔ540 = -2.23δ + 15.95 (1) without agitation △Ｔ540 = -6.17δ + 50.47 (2) Therefore, the thickness of the nickel oxide film can be controlled with the gelatin thickness. If electrodeposition of nickel oxide is carried out onto a ITO glass through a gelatin film with various thickness, a 3-dimensional nickel oxide film would be expected. A relationship between current and time was derived methematically for step potential method in a electrochromic process: Dπ**2t 2FDC。 ln│i│ = - ─── ─ + ln ── (3) 4h**2 h With the nickel oxide film thickness of 25nm, the diffusivities of hydrogen atom were calculated 2.7x10**-13cm**2 /sec and 7.0x10**-13cm**2/sec for coloration and bleaching processes, respectively.
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Ren, Tingting. "Morphology and optical property control of electrodeposited zinc oxide /". 2006. http://collections.mun.ca/u?/theses,85163.
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Yi-HaoLee y 李翊豪. "Fabrication of Cu2ZnSnS4 (CZTS) Thin Film via Sulfurization of Electrodeposited Precursors". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/86158008695580505110.
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碩士國立成功大學
機械工程學系碩博士班
100
Nowadays, people try to find a substitute of Cu(In, Ga)Se2 (CIGS) on research of solar cells. Cu(In, Ga)Se2 (CIGS) has high cost and toxicity these two defects. Cu2ZnSnS4 (CZTS) thin films are one of the most promising materials for low-cost and low-toxicity thin-film solar cells since they consist of abundant materials. Therefore, Cu2ZnSnS4 (CZTS) has become a good candidate to substitute CIGS. This thesis used non-vacuum process to fabricate Cu2ZnSnS4 (CZTS) thin films. Innovative layer-by-layer electrodeposition method was done. The precursors (Cu/Zn/Sn stacked layers) were deposited by electrodeposited sequentially onto Mo-coated glass substrates. The electrodeposition bath was clear, durable. The process was repeatable and used just few minutes. The precursors were sulfurized by annealing in H2S gas atmosphere. The Cu2ZnSnS4 (CZTS) thin films were analyzed and verified by energy dispersive spectroscopy (EDS), scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The atom composition ratio could be controlled by adjusted electrodeposition parameter.
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Chen, Chien-Fu y 陳建夫. "Magnetic and Structural Properties of Electrodeposited Nickel thin film on ITO". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/83123411954971115317.
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碩士國立臺北教育大學
自然科學教育學系碩士班
101
In this study, we discuss the impact on the H3BO3 with NiSO4 and nickel-plated conductive glass ITO. Preliminary experiment is using Cyclic Voltammetry (CV) to identify the most suitable voltage range, then with the way of the fixed electroplating voltage to get the relationship of current versus time (referred to as CA). And last, using measurement instruments to observe Ni on the ITO nucleation mechanism. We found that passing through the nickel peak, the current increased, speculating that hydrogen evolution reaction (HER) and the magnetic of nanoparticles are at this stage; the longer the time of HER the higher the hydroxide oxidation peak, while adding the boric acid reduce its peak value, which means that the boric acid plays an important role in this reaction. When the H3BO3 of 0.02M, nickel (-0.988)V electroplating to 60mC, the magnetic phase transition occurs; And we will rise voltage to 1.5V, the characteristics will advance to the number of low-Coulomb, and we speculated that a lot of factors from structural deformation leads to stress, which called the magnetic phase transitions.
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Chen, Yong-Yun y 陳泳澐. "Study of solar selective absorbing film by electrodeposited Ni-WC composite coatings". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/ue8mz9.
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碩士國立高雄應用科技大學
機械與精密工程研究所
104
Solar thermal industry has been in the current state of development, the more common of the products for the solar pond and water heaters. The possibility of civilian power generation costs of its rich technology and more suitable to the development of solar energy applications in high temperatures, the developmental potential is limitless. This study used composite plating method, add WC powder Electroplating Ni - WC Composite plating layer in Watts bath, has the highest absorption rate in WC 40g / L, it can reach 0.956. And the surface morphology was observed by SEM. other analysis include the temperature rise efficiency hardness and corrosion resistance, but found it have poor adhesion and low hardness; Therefore, the inclusion of other additives to improve its mechanical properties, corrosion resistance and should increase plating HV 126 absorption rate of up to 0.944.
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Yi, Kuo y 郭翊. "Electrochromic properties of tungsten oxide thin film deposited by two-electrode electrodeposited process". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/90942979468387544008.
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碩士國立臺灣師範大學
機電科技學系
101
In this study, electrodeposition method was used to fabricate WO3 electrochromic thin film. To obtain better electrochromic property of device, the solution was aged with different days before depositing process. Furthermore, some thin films were annealed to explore its effect on the electrochromic property of the device. The experiments of this study were divided into three parts. The first part was to use a two-electrode electrodepositing system to form WO3 thin film and find the start voltage of electrodeposition. The fixed voltage mode was used to fabricate the WO3 thin film. The second part was to explore the difference of the electrochromic property of thin film deposited by different ageing time. Finally, some thin films were annealed in the third part to observe the variety of properties including colored/bleached charge, coloring efficiency and current leakage difference. According to the experimental results, the starting voltage for depositing film is about 0.922 V and the best colored/bleached electric voltage is 2.5 V. The thickness of WO3 thin film is about 300 nm when the operating parameter has been controlled at 1.5 V and 2 minutes. The surface roughness of thin films before annealing is about 1~1.5 nm, and it reduced to about 1 nm after annealing process. The four days aged of solution before depositing thin film can achieve the best electrochromic properties, which makes the thin film have the transmittance difference of 54.3%, optical density difference of 0.48, and coloring efficiency of 37.3 cm2/coul and the recovery rate of 95%. The thin film annealed at 100℃ makes the devices have relatively poor color efficiency and recovery rate, about 14.1 cm2/coul and 35%, respectively. According to the electrical measurements of the films annealed at 300℃, it has been proved that the devices have higher current leakage and a narrow hysteresis region, which will make the colored and bleached of thin film is hard to develop.
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Hsueh-PingLiu y 劉學平. "Study of boron doped CdS used in electrodeposited CuInSe2 thin film solar cell". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/29824812563868680010.
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Chen-TingLeng y 冷貞廷. "Study of electrodeposited CuInSe2 absorption layer on CdS/CuInSe2 thin film solar cell". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/74761566527254583756.
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碩士國立成功大學
微電子工程研究所
104
CuInSe2 films were fabricated on Mo-coated glass by electro-deposition and selenization processes. The CuInSe2 precursors were selenized at different temperature to enhance the quality and crystallinity. In order to improve the performance of CuInSe2 thin film solar cell, the chemical composition of CuInSe2 absorption layer under different selenization pressure were studied. The relationship between temperature dropping rate and open circuit voltage (Voc) of solar cells was investigated. The value of the Voc was also improved by KCN and I solution surface treatment, sequentially. The solar cell with the AZO/CdS/CIS/Mo/Glass structure was fabricated and the conversion efficiency of 2.82% was obtained.
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Deng, Yu-Ting y 鄧伃庭. "Electrodeposited Film Electrodes Derived from Dinitrosyl Iron Complex/CoSO4/NiSO4 for Water Splitting". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/z95kde.
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Hsieh, Herng y 謝珩. "Analyses of electrodeposited CdTe film properties : effects of pH values, temperatures and deposition voltages". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/a98922.
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碩士國立東華大學
電機工程學系
101
The effects of deposition parameters including the solution temperatures, pH values, and deposition voltages on the properties of CdTe films were investigated. The CBD process was employed to grow the n-type CdS layers on the ITO glass substrates. A three-electrode electrodeposition system was applied to grow the CdTe films. The p-type CdTe layers were electrodeposited on the CdS-coated ITO substrates. Both of the pH value and deposition temperatures had significant impacts on the CdTe films. In addition, the deposition voltages influenced the stoichiometric ratios and crystalline of as-deposited films.
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Chen, Huei-Hsin Kalu Peter N. "Characterization and nanostructure analysis of electrodeposited CuInSe₂ thin film for applications in flexible solar cells". 2006. http://etd.lib.fsu.edu/theses/available/etd-05062006-173437.
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Thesis (M.S.)--Florida State University, 2006.Advisor: Peter Kalu, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Sept. 22, 2006). Document formatted into pages; contains x, 77 pages. Includes bibliographical references.
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CHEN, Guan-Shen y 陳冠珅. "Effect of the sputtered nickel nano film on photoelectrochemical properties of the electrodeposited cuprous oxide". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/64957085242109333707.
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碩士明志科技大學
材料工程系碩士班
103
With the continued reduction in global crude oil content and other energy resources, people in the world faces an energy crisis. Finding new alternative energy sources becomes an urgent issue. Hydrogen has the potential to become an important source of energy in the future, because it is universally abundant. Splitting water by applying solar energy and photoelectrochemical reaction is one of the most valuable research domains. Cuprous oxide (Cu2O) with a theoretical band gap of ca. 2.0〜2.2 eV, is a p-type semiconductor. The absorption rate for visible light is relatively high. So it has potential to be used as an electrode for production of hydrogen in the photoelectrochemical reaction In this research, p-type Cu2O films were electrodeposited on the commercial n-type FTO glass. All deposited Cu2O films have (111) preferred orientation. The films were then annealed and sputtered with nickel (Ni) nano film on the surface. The finished films were used as working electrodes for photoelectrochemical experiments. A potentiostat with counter electrode of Pt or graphene was used for the experiment. Experimental results show that all samples are electrochemically active to the irradiation of visible light. The sample, which was sputtered with nickel film of 3 nm thick followed by annealing at 200 ℃, generated the highest photoelectrochemical current. The sample structure was further investigated in TEM, showing that the nickel film after annealing is discontinuous. The discontinuous nickel film has an effect of reducing catalytic reaction, and thus enhances the reduction of hydrogen. In this research, graphene was tried to replace Pt as a counter electrode. Results show that the reaction current value is almost the same by using Pt as the counter electrode. Thus, the graphene can really replace expensive platinum as a counter electrode.
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Li, Nian-Ze y 李念澤. "Effect of silver and nickel nanoparticles on photoelectrochemical properties of the electrodeposited cuprous oxide film". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/89550961307440460558.
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碩士明志科技大學
材料工程研究所
101
In this syudy, Cu2O films were electrodeposited on the FTO transparent conducting glass。A conventional cell of 3-electrodes was used for the photoelectrochemical testings。The water solution for the experiments consists of 0.5 M Na2SO4。All samples are (111) prefer-orientated。 On Cu2O films respectively of the sputtering 1 nm，3 nm and 5 nm films of Ag and Ni。The sample subjected to 200℃，300℃ and 400℃ of the rapid thermal annealing. A halogen lamp of 150 W was used as the light source for the experiment of photoelectrochemical properties。Structure and composition of the films were detected by using using XRD，FE-SEM，EDS and XPS。 Experimental results showed that Cu2O films with the annealing temperature is higher with particle generation。When adding the thickness of the silver particles also increased，According to XRD results，After annealing of 400 ℃ generated a large number of copper phase，Sputtered Ni produced a few Cu particles at annealing temperature 300 ℃。The LSV test Cu2O film and sputtering Ag found that annealing at 200 ℃ photoelectric properties optimal annealing temperature of 300 ℃ begin to decline。Sputtering Ni is the best properties，with the increase of annealing temperature decreased photoelectric properties。ICP analysis showed，When increasing thickness of Ag，Cu metal ion content increased decomposition。With increase of Ni thickness，Cu was reduced decomposition of metal ions。Have the lowest contents in Ni layer of 3 nm。Lower decomposition of Ni sputtering。In the XPS investigation。In Cu2O films the main peak is CuO (933.55eV)，The second is the Cu(OH)2 (934.08eV)。Because surface layer of the deposited Cu2O was further oxidized to CuO during drying and handling of samples in the ambient atmosphere。Cu2O specimen of Sputtering Ni 3 nm by potentiostatic，The amount of reduction of CuO into Cu2O is very low。The results show that the Ni layer can inhibit reduction of CuO into Cu2O on the electrode surface。
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Du, Chen-Hao y 杜振豪. "The use of electrodeposited zinc oxide nanorod array as the sensing film for glucose sensing EGFET". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/95114997097197469363.
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LI, ZONG-RU y 李宗儒. "Effect of Hot pressing-Annealing on Thermoelectric Properties of 3-dimension Bismuth-Telluride-based Film Electrodeposited on Polystyrene Sphere Template". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/p83fn7.
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碩士國立中正大學
化學工程研究所
102
This study was to investigate the properties of three-dimensional Bi2Te3-based thin films prepared by potentiostatic electrodeposition technique onto three-dimensional polystyrene templates which were formed on stainless steel substrates via blade coating method. Temperature were fixed at 30oC and agitated at a speed of 340 rpm during electrodeposition process. A hot pressing-annealing method was applied after electroplating process to enhance thermoelectric properties. In order to obtainthe optimal operational conditions, these films were used for electrochemical, compositional and thermoelectrical analysis. It was found that p-type Bismuth-Antimony-Telluride and n-type Bismuth-Telluride-Selenium thin films which were deposited at a constant potential of -0.2V and -0.06V vs. Ag/Ag Clare the closest to ideal composition. The thermoelectrical analysis results show that both Seebeck coefficient and electrical resistivity were reduced after hot pressing treatment. That could be attributed to the raising pressure and temperature which forced atoms to rearrange during hot pressing-annealing process. The treatment will further reduce the lattice defects and make structure tighter. Although thermal conductivity would also increased by this phenomenon but it is almost disproportionate compared to electrical resistivity drop, and the Seebeck coefficient decreases. The carrier concentration and mobility presented down ward and upward trend respectively with processing time extend. In terms of performance, the maximum power factorof the films studies is 555μW/K2m for p-type Bismuth-Antimony-Telluride and 397μW/K2m forn-type Bismuth-Telluride-Selenium. Both of these two samples were prepared under the conditions of 290oC and 195kgf/cm2 after current assisted hot pressing-annealing treatment for 60 min.
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YOU, FU-CHIUAN y 游福全. "Effects of Current-Assisted Hot Pressing and Annealing on Thermoelectric Properties of Bismuth-Telluride-based Film Electrodeposited on Its Seeding Layer". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/32427619999137589796.
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碩士國立中正大學
化學工程研究所
104
This study used potentiostatic electrodeposition technique to prepare three-dimensional Bi2Te3-based thin films within nanoscale polystyrene templates, which were premade on the top of P-type or N-type seeding layer via blade coating method. Processing temperature were fixed to 30oC and agitated with a speed of 300rpm during electroplating. To enhance thermoelectric properties, a current assisted hot pressing and annealing method was applied to films after electroplating. The different electrodeposition potential, templates removed time and after-treatment methods has been chosen in order to investigate the effects of parameters on thermoelectrical properties. The results showing that P-type bismuth-antimony-telluride and N-type bismuth-telluride-selenium thin films, which were deposited at a constant potential -0.45V and -0.32V vs. Ag/AgCl, KCl3m were the closest one to the ideal composition. It’s also found that if there were any polystyrene templates been left over the films will drop thermoelectrical properties dramatically. In after-treatments aspect, due to specimen after hot pressing and annealing and current assisted hot pressing treatment, that the original loose structure becomes densified thus reducing resistivity; the other hand atoms to rearrange during process which will reduce the lattice defects so that carrier concentration is reduced to improve the carrier mobility. In terms of performance, the maximum power factor in this study is 1496.12μW/K2m for P-type bismuth-antimony-telluride and is 1073.87μW/K2m for N-type bismuth-telluride-selenium. Both samples were prepared under the conditions of 290oC and 195kgf/cm2 and current density 1600A/cm2.
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Chun-Wang y 王駿. "Study of Corrosion Behavior for the Thermally Grown Oxide Film and Electrodeposited Polypyrrole Coatings 316 Stainless Steel in the Sea Water and Sulphuric Acid Solution Environments". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/5t5233.
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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在職專班
101
In this study, the corrosion behavior of thermally grown oxide film and polypyrrole coatings using cyclic voltammetry were prepared on SS 316 stainless steel are investigated in natural sea water and 0.5 M sulphuric acid solution environments. The corrosion properties of these materials are studied using a potentiodynamic polarization test. The polarization curves and scanning electron microscopy (FE-SEM) of both thermally grown oxide film and polypyrrole coating specimens are also studied. The experimental results show that the heat-treated sample of 800℃for 30 min has better corrosion resistance than the base SS 316 in natural sea water. In 0.5 M sulphuric acid solution environment, it was found the corrosion potential of the polypyrrole-coated and heat-treated specimens shifted toward a noble potential, and a significant decrease in corrosion current density was also observed Therefore, both the thermally grown oxide film and polypyrrole coating can offer SS 316 higher corrosion resistance in 0.5 M sulphuric acid solution environment.
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Wang, Li-Ting y 王麗婷. "Characterizations of electrodeposited CuInSe2 thin films". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/95ee3z.
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碩士國立東華大學
光電工程研究所
96
In this study, the CuInSe2 (CIS) films were deposited by electrodeposition (ED) technique at room temperature. With a Pt mesh of counter electrode, a Ag/AgCl of reference electrode, and a the molybdenum (Mo) coated glass substrate of working electrode, the classical three-electrode potential method was employed to deposit the CuInSe2 films. The electrolyte bath for the deposition of CuInSe2 films contained the solution of 15~22 mM copper chloride hydrate, 25~36 mM indium chloride, and 35~45 mM selenium oxide. Triethanolamine and lithium chloride were used as complexing agents in the bath. The pH of the chemical bath was adjusted by adding the drops of dilute hydrochloric and ammonia solution. The effects of the concentration of reagents, applied potential/current, deposition time, and complexing agents on film compositions were studied. The surface morphology, film compositions, and crystal structures were characterized by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction, respectively. The results revealed that the compositions of CIS thin films were Cu-rich, presenting that the copper ions are more activated than the indium ions during deposition. With various concentrations of different complexing agents, the properties of as-deposited CIS thin films were investigated. The near ideal stoichiometery of atomic ratio [Cu]:[In]:[Se] = 23.81%:26.43%:49.76% was achieved by optimizing the deposition conditions. The as-deposited films annealed at 350 °C for 45 min under different atmospheres improved the quality and crystallization of the precursor films.
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Li, Chin-chang y 李淇彰. "Electrodepositon of Thin Platinum Film via Surfactant Assembly". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93571162166541886395.
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碩士國立成功大學
材料科學及工程學系碩博士班
95
In recent years, hydrogen has been one of the important source of energy, and in a photovoltaic cell hydrogen is produced by water splitting. The purpose of the thesis is to make the cathode for photovoltaic cell in order to raise the efficiency of water splitting by varying surface morphology of platinum thin film. In this thesis, nanostructure platinum thin film was prepared by utilizing surfactant assembly to investigate the effects of experimental parameters, such as electrical potential、surfactant concentration and deposition time. The wormhole-like platinum thin film could be prepared by electrodeposition, and its size is 7.5 nm. There are three important results obtained in this study. First, the wormhole-like platinum thin film could be prepared at -0.2, and -0.4 volt. Second, the size of wormhole increases from 7.5 to 15 nm by varying 0.1 to 1 percent of surfactant concentration. Third, the wormhole -like platinum thin film could be prepared easily by slowing the deposition rate. The highest surface area obtained is 42.1m2/g and the hydrogen conversion efficiency is 20.2% when the platinum is deposited at -0.4 volt, and the surfactant concentration of 0.1 percent. The highest symmetrical current is 112mA/cm2 as calculated by electrode kinetics.
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Gong, JEK y 龔盈宇. "Electrodeposited Ga/As Films and Its Photoelectrochemical Characterization". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/39784952304047600092.
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Tsai, Yi-Ting y 蔡議霆. "Structure and photoelectrochemical properties of electrodeposited p-Cu2O films". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/95477266205519086432.
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碩士明志科技大學
材料工程研究所
98
Hydrogen (H2) has the potential in the future alternative energy because of its abundance on earth. Therefore, many researchers are attracted to develop hydrogen production with more efficient methods. The application of the photoelectrochemical (PEC) effect of some oxides is one of the most promising measures. Copper(I) oxide (Cu2O) is an attractive oxide of p-Type semiconductor in this regard. It has several advantages, such as: (1) band gap energy of 2.0–2.2 eV, (2) high absorption coefficient over the wavelength range in the solar spectrum, (3) non-toxic and (4) highly abundant. In this study, p-type Cu2O films were electrodeposited in a bath composed of an aqueous solution of Cu2SO4 stabilized with lactic acid as chelating agent. The pH value of the electrolyte was adjusted by adding a NaOH aqueous solution. The photoelectrochemical response of films with (111) preferred orientation was measured on a potentiostat electrochemical analyzer. A halogen lamp of 150 W was used as the light source. XRD, XPS and FE-SEM were used for structural investigations. Experimental results show that Cu2O films have strong photoelectrochemical response. In the XPS investigation, surface layer of the deposited Cu2O was further oxidized to CuO during drying and handling of samples in the ambient atmosphere. After cyclic voltammetry (CV) test, Cu(OH)2 layer was deposited on the surface, according to the XPS experimental results. The fact reveals that Cu2O was reduced to pure copper in the cathodic reaction and further oxidized to Cu(OH)2 in the anodic reaction. The reduction was confirmed by the ICP experiment of the electrolyte after the cathodic reaction.
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CHEN, WEN HSING y 陳汶杏. "Argon Ion Laser Annealing of Electrodeposited CuInSe2 Thin Films". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/48849887117501717052.
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碩士國立成功大學
化學系
87
Ploycrystalline CuInSe2(CIS) thin films were electrodeposited by constant potential electrolysis on molybdenum(Mo) sheet using CuCl2, InCl3, and SeO2 as electrolyte solution containing triethanolamine(TEA) as a complexing agent. The films were annealed in an inert atmosphere by an argon-ion laser operating on all green lines with the power and annealed time varied. The annealed CIS thin fillms were characterized by X-ray diffractometry(XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy(EDS). The maximum temperature-rise by different incident laser powers were calculated theoretically. The results show that varing the laser power and annealing time affect the stoichiometry of CIS; produving binary phase such as Cu9In4, CuSe and CuSe2 along with the ternary CIS.
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Cross, Andrew D. "Electrodeposited thin films of manganese dioxide for electrochemical capacitors". Thesis, 2018. http://hdl.handle.net/1959.13/1388292.
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Research Doctorate - Doctor of Philosophy (PhD)This thesis details the search for factors which influence the electrochemically capacitive performance of electrodeposited thin films of manganese dioxide (MnO₂). In the initial investigation (Chapter Two), the focus was on altering deposition conditions (i.e., solution composition, deposition potential, duration of deposition, and deposition solution temperature), and observing the resultant capacitive behaviour. From these experiments, the best performing materials showed an improvement in specific capacitance of at least 250% over other materials reported in the literature. Analysis of the results showed a link between slower mass transport characteristics of electro-active species during deposition, and an improvement on the resulting specific capacitance. Improved specific capacitance was thought to relate to an increase in the access of cycling electrolyte to the electrode surface, i.e., an increase in electrode surface area. Additionally, an inversely proportional relationship between deposition time and specific capacitance was also established. The second article (Chapter Three) compared films formed during constant-potential (chronoamperometry) and constant-current (galvanostatic) deposition protocols. While galvanostatic deposition protocols did not tend to yield higher specific capacitances than their equivalent chronoamperometric experiments, some possible insight into the deposition of manganese dioxide was gained. The third article (Chapter Four), more closely examines changes in mass during chronoamperometric electrodeposition. The work compared mass of electrode thin films calculated during deposition via three methods. This article discussed the results in terms of underlying assumptions associated with each of these methods, and any complicating factors which may influence mass calculation. The fourth and final article (Chapter Five), extends on from the work in Chapter Four, with a focus on the effect of altering the anions present during deposition. Anomalous behaviour of the chloride-containing system were hypothesised to be due to a combination of the enhanced stability of the Mn(III) intermediate in certain solution conditions, and the tendency of the available chloride ions to complex with this manganese species. In these final two studies, the capacitive behaviour of the manganese dioxide thin films was also compared.
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Pattanaik, Gyana R. "Giant magnetoresistive studies of electrodeposited cu-cogranular thin films". Thesis, 2001. http://localhost:8080/iit/handle/2074/4203.
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