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 vs 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 stick the scotch tape on the sample, then peel off the tape and see 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 indicate that the Cu nucleation process in the sulfuric bath is slower than in the borate bath. In both baths, nucleation kinetics do 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.

In this work, the possibility of Cu electrodeposition on Ru-Ta alloy thin films is explored. Ru and Ta were sputter deposited on Si substrate with different composition verified by RBS. Four point probe, XRD, TEM and AFM were used to study the properties of Ru-Ta thin films such as sheet resistance, crystallinity, grain size, etc. Cyclic voltammetry is used to study the Cu electrodeposition characteristics on Ru-Ta after various surface pretreatments. The results provide insights on the removal of Ta oxide such that it enables better Cu nucleation and adhesion. Bimetallic corrosion of Cu on modified Ru-Ta surface was studied in CMP related chemicals. In Cu interconnect fabrication process, the making of trenches and vias on low-k dielectric films involves the application of fluorocarbon plasma etch gases. Cu microdots deposited on Ru and Ta substrate were treated by fluorocarbon plasma etch gases such as CF4, CF4+O2, CH2F2, C4F8 and SF6 and investigated by using x-ray photoelectron spectroscopy, contact angle measurement and electrochemical techniques. Micropattern corrosion screening technique was used to measure the corrosion rate of plasma treated Cu. XPS results revealed different surface chemistry on Cu after treating with plasma etching. The fluorine/carbon ratio of the etching gases results in different extent of fluorocarbon polymer residues and affects the cleaning efficiency and Cu corrosion trends.

Electrodeposition is a novel method for fabrication of diamond-like carbon (DLC) films on metal substrates. In this work, DLC was electrochemically deposited on different substrates based on an anodic oxidation cyclization of acetylene in liquid ammonia. Successfully anodic deposition was carried out for DLC onto nickel substrate at temperatures below -40°C. Comparative studies were performed on a series of different carbon sources (acetylene, sodium acetylide, and a mixture of acetylene and sodium acetylide). The films were characterized using a variety of methods including Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), XPS valence band spectra, and/or scanning electron microscopy (SEM). Raman spectroscopy is used as a bench mark technique to verify the presence of deposited DLC films, to access the films homogeneities, and to provide the ratio of the different carbon phases, mainly disordered graphite (D) and graphite (G) phases in the films. A combination of the Raman with FTIR and valence band spectra analysis allowed the distinction between hydrogenated DLC and unhydrogenated DLC films. Three different kinds of DLC [(1) hydrogenated DLC (a-C:H); (2) tetrahedral hydrogenated DLC (ta-C:H); and (3) graphitic-like DLC] were deposited depending upon the deposition conditions and substrates. Temperature and current density are the most important parameters to govern the quality of the deposited films, where adding of acetylide into the electrolyte led to films with a higher degree of graphitic phases. The proposed mechanism for acetylene anodic oxidation does not involve direct electron transfer but electrochemical cyclization of acetylene radical cations and hydrogen abstraction at the termination steps. Sodium acetylide, however, dissociates to an acetylenic ion, C2H-, in liquid ammonia. The electrochemistry heterogeneity also leads to island and two-dimensional (2D) nucleation growth of DLC films. Different bond formations of metal to carbon and different chemisorptions of acetylene on metal play important roles in governing the film properties. Using mixed C2HNa and C2H2 as electrolyte, polycrystalline diamond and hexagonal diamond are formed on Mo and stainless steel, respectively. This is the first time to report that polycrystalline diamond can be grown electrochemically at temperature below -40ºC. The preliminary studies on substrate pretreatment with diamond powder and SiC 600 are studied. The effect of the substrate on the film quality for the electrodeposited DLC films described herein is similar to that for diamond deposition via chemical vapor deposition (CVD).

京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第22551号 / エネ博第402号 / 新制||エネ||77(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 野平 俊之, 教授 萩原 理加, 教授 佐川 尚 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DGAM

This work deals with issues of electrochromism and making active electrochromic film of titanium dioxide. By using various precursors consisting titanium element active film was electrodeposited on glass substrates covered with transparent conductive thin-film In2O3:Sn (ITO). Electrochromic characteristics of these substrates that were electrodeposited for different times and with different voltage have been studied. Than there has been studied the impact of various annealing temperatures on electrochromic characteristics.

Un nanotube de dioxyde de titane autoporteur (TiO2 nts) est exploré en tant qu’électrode négative potentielle pour les microbatteries Li-ion 3D. Différentes modifications chimiques du TiO2 ont été explorées et étudiées, comme le TiO2 allié au Nb, le TiO2 revêtu d'ALD-Al2O3, le titanate de lithium-TiO2 et le TiO2 sulfuré. Le dépôt d'électrolyte polymère à base de PEO (oxyde d'éthylène) (PMMA-PEG) portant le sel de LiTFSI dans du TiO2 a été obtenu par la réaction d'électropolymérisation sur l'anode TiO2 et la cathode Lithum nickel oxyde de manganèse (LNMO). L'objectif principal ici était d'exploiter la surface active des électrodes par électrodéposition et d'améliorer ainsi l'interface électrode-électrolyte. Une telle micro-batterie contenant des électrodes revêtues de polymère révèle que les valeurs de capacité obtenues à différents taux de C sont doublées lorsque les électrodes sont complètement remplies par l'électrolyte polymère par rapport à la micro-batterie à électrodes brutes. Les excellentes performances électrochimiques sont attribuées aux interfaces électrode-électrolyte améliorées dans les deux électrodes / Self-supported titanium dioxide nanotube (TiO2 nts) is explored as a potential negative electrode for 3D Li-ion microbatteries. Different chemical modifications on the TiO2 nts have been explored and studied like Nb-alloyed TiO2 nts, ALD-Al2O3 coated TiO2 nts, Lithium titanate-TiO2 nts and sulphurized TiO2 nts. The deposition of PEO (polyethylene oxide) based polymer electrolyte (PMMA-PEG) carrying LiTFSI salt into TiO2 nts has been achieved by the electropolymerization reaction on the TiO2 nts anode and the Lithum nickel manganese oxide (LNMO) cathode. The main aim here was to exploit the active surface area of the electrodes using electrodeposition and there by enhance the electrode-electrolyte interface. Such a microbattery containing polymer-coated electrodes reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte compared with the microbattery with the raw electrodes. The excellent electrochemical performance is attributed to the improved electrode-electrolyte interfaces in both the electrodes

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18999号 / 工博第4041号 / 新制||工||1622(附属図書館) / 31950 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 作花 哲夫, 教授 安部 武志, 教授 邑瀬 邦明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This dissertation presents studies electrodeposited MoS2 and metal-doped MoS2 thin films, and their performance for energy storage, catalysis, and biosensor applications. Ni-doped MoS2 thin films were fabricated by electrodeposition from electrolytes containing both MoS42- and varying concentrations of Ni2+, followed by annealing at 400 ºC for 2 h in an Ar atmosphere. The film resistivity increased from 11.3 µΩ-cm for un-doped MoS2 to 32.8 µΩ-cm for Ni-doped MoS2 containing 9 atom% Ni. For all Ni dopant levels studied, only the x-ray diffraction (XRD) pattern expected for MoS2 is observed, with the average grain size increases with increasing Ni content. Ni-doped MoS2 thin films were tested for their activity towards the hydrogen evolution reaction (HER) in 0.5M H2SO4. Tafel equation fits reveal that the catalytic activity for HER, as measured by the exchange current density, increases up to 6 atom% Ni, and then decreases slightly for 9 atom% Ni. Ni-doped MoS2 thin films were also tested in 1.0 M Na2SO4 for use within electrochemical supercapacitors, and the capacitance per unit area increases by 2-3x for 9 atom% Ni-doped MoS2 relative to un-doped MoS2. The highest specific capacitance obtained for Ni-doped MoS2 during galvanostatic charge-discharge measurements is ~300 F/g

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