Ce travail s'inscrit dans le cadre de la recherche d'une amélioration des conditions de réalisation des dispositifs photovoltaïques à base du matériau semiconducteur ternaire CuInS2, qui doit constituer la couche absorbante dans la cellule solaire. Différentes techniques économiquement rentables ont été retenues pour l'élaboration de ce matériau : nous avons sélectionné le dépôt chimique en solution (CBD), la pulvérisation chimique réactive avec air (spray) et la pulvérisation chimique réactive sans air (PSA). Les matériaux élaborés ont été inclus dans des dispositifs photovoltaïques, pour lesquels le CuInS2 est réalisé soit avec la méthode PSA (CuInS2/ZnO/SnO2/verre ou CuInS2/In2S3/ZnO/SnO2/verre), soit avec la méthode de spray (CuInS2/In2S3:Al/SnO2/pyrex ou CuInS2/ZnS:In/SnO2/pyrex).Globalement, les propriétés structurales, morphologiques et optiques sont satisfaisantes. Pour les cellules incluant le CuInS2 déposé par spray, le photo-courant existe et atteint jusqu'à 200 µA dans le cas de la cellule CuInS2/ZnS:In/SnO2/pyrex, ou environ 4 A/cm2. / Photovoltaic solar cells based on I–III–VI2 ternary chalcopyrite absorber layers, have been the focus of intense investigation for over two decades. The use of chalcopyrite absorbers are highly appealing since their bandgaps correlate well to the maximum photon power density in the solar spectrum. Cu-chalcopyrite semiconductors have been studied extensively in recent years due to their applications as absorbers for large-area low-cost photovoltaic devices. CuInS2 as a chalcopyrite-semiconductor material has a direct band gap of 1.5 eV, a high absorption coefficient and nontoxic constituents and is, therefore, a promising candidate for photovoltaic applications. Different methods have been used to prepare CuInS2 films. Among these methods, spray pyrolysis, used in the present study, is an attractive one because large-area films with good uniformity may be prepared at low cost.

No description available.

Membrane fouling, which is caused by deposition/adsorption of foulants on the surface or within membrane pores, still remains a bottleneck that hampers the widespread application of membrane bioreactor (MBR) technology for wastewater treatment. Recently membrane surface modification has proved to be a useful method in water/wastewater treatment to improve the surface hydrophilicity of membranes to obtain higher water fluxes and to reduce fouling. In this study, membrane modification was investigated by depositing a thin film of same thickness of TiO2 on the surface of an ultrafiltration alumina membrane. Various thin-film deposition (TFD) methods were employed, i.e. electron-beam evaporation, sputter and atomic layer deposition (ALD), and a comparative study of the methods was conducted to assess fouling inhibition performance in a lab-scale anaerobic MBR (AnMBR) fed with synthetic municipal wastewater. Thorough surface characterization of all modified membranes was carried out along with clean water permeability (CWP) tests and fouling behavior by bovine serum albumin (BSA) adsorption tests. The study showed better fouling inhibition performance of all modified membranes; however the effect varied due to different surface characteristics obtained by different deposition methods. As a result, ALD-modified membrane showed a superior status in terms of surface characteristics and fouling inhibition performance in AnMBR filtration tests. Hence ALD was determined to be the best TFD method for alumina membrane surface modification for this study. ALD-modified membranes were further characterized to determine an optimum thickness of TiO2-film by applying different ALD cycles. ALD treatment significantly improved the surface hydrophilicity of the unmodified membrane. Also ALD-TiO2 modification was observed to reduce the surface roughness of original alumina membrane, which in turn enhanced the anti-fouling properties of modified membranes. Finally, a same thickness of ALD-TiO2 and ALD-SnO2 modified membranes were tested for alginate fouling inhibition performance in a dead-end constant-pressure filtration system. This is the first report on the application of SnO2-modified ceramic membrane for testing its alginate fouling potential; which was determined to be nearly-same for both modified membranes with a negligible amount of difference. This revealed SnO2 as a potential future anti-foulant to be tested for membrane modification/fabrication for application in water/wastewater treatment systems.

In today’s electronics, transistors are the main building blocks of the vast majority of electronic devices and integrated circuits. Types of transistors vary depending on the device structure and operation principle. Metal-oxide-based thin film transistors (MO TFTs), in particular, are an emerging technology that has a promising future in many applications, such as large-area display and wearable electronics. It exhibits unique features that make it superior to the existing Si-based technology, such as optical transparency and mechanical flexibility. However, some technical challenges in MO TFTs limit their emplyoment in today’s applications, such as low carrier mobility and high processing temperature. Solution-processed MO TFT based on spray pyrolysis combined with a carefully engineered TFT structure offers a dramatically enhance carrier mobility at low processing temperature. In this work, we are utilizing spray pyrolysis to grow In2O3 and ZnO based TFTs at low processing temperature. The structural effects of the channel layer on the electrical performance is investigated in two parts. The first part highlights the impact of thickness of the channel layer on the device performance of both In2O3 and ZnO, while the second part explores In2O3/ZnO heterojunction-based active layer. The results showed that increasing the channel thickness of both In2O3 and ZnO based TFTs enhanced the carrier mobility due to a reduced surface-roughness scattering effect. In addition, evidence showed that the electron transport mechanism in In2O3/ZnO heterojunction transitioned from trap-limited conduction (TLC) to percolation conduction (PC) process. Thanks to the existence of a 2D-confined electron sheet at the atomically sharp In2O3/ZnO heterointerface, the electron mobility was dramatically enhanced.

京都大学 / 新制・論文博士 / 博士(理学) / 乙第13396号 / 論理博第1575号 / 新制||理||1678(附属図書館) / (主査)教授 北川 宏, 教授 吉村 一良, 教授 有賀 哲也 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM

This thesis presents a thermal gradient gas chromatography (TGGC) system that is implemented on a micro-scale. The GC column is approximately 20 cm long and is fabricated out of silicon with 21 nickel thin-film heaters evenly placed along the length of the column. Computational heat transfer models using ANSYS Mechanical APDL predict heating and cooling rates up to 32,000 deg C/min and 3,600 deg C/min, respectively. These results are verified through testing an experimental silicon channel. A PI controller which uses resistance measurements to calculate thin-film temperature is used for obtaining dynamic thermal gradient control. This controller is shown to possess a characteristic rise time of approximately 0.3 seconds with less than 4% overshoot and precision to within less than a degree. These characteristics present this system as a highly favorable candidate for a micro-GC column with resolution similar to that of conventional GC.

The mapping of the refractive index of cells has been extensively studied since 1950s. This optical parameter constitutes a key biophysical property strongly correlated to fundamental cell parameters such, e.g., intracellular mass distribution and protein concentration. Experimental studies evidence that the cell refractive index (Refractive Index) provides critical insights to understand diverse cellular structures and interpret pathological states, including diverse stages of diseases. However, measuring the refractive indices of biological specimens satisfying clinical requirements is currently challenging, since there is a lack of spectral signatures of sub-cellular components in the visible range due to their transparent nature. Designing methods capable of extracting visible fingerprints of cellular components remains attracting large research interests. In this work, I have contributed to this project by fabricating and characterizing a black nanostructured membrane that dynamically interacts with cancerous cells and furnishes label-free structural color generation by exploiting the inherent contrast mechanisms of them. Thus, adequately meeting morphology differentiation to assist in biomedical research. I have tested the system with HCT116 colorectal cancer cells. In addition, this special membrane allows refractive index recovery and cell thickness mapping with commonly available bright-field microscopy equipment. Therefore, it is of considerable clinical importance to allow the generation of qualitative information about cell morphology to add in medicine and biophysics research.

<div>Thin films with selective spectral properties have great potential for use in applications such as solar thermal absorbers, selective thermal emitters, thermal barrier coatings, and thermophotovoltaics. Understanding the dependence of their optical properties with temperature is crucial for practical applications. Relatively less-used films with high thermal stability, high refractive index, and infrared transparency, such as cerium oxide CeO2 and magnesium oxide (MgO) have not been studied extensively for high-temperature applications. In this paper, CeO2, MgO, and several multilayer samples containing these compounds will be studied their change of optical properties with increasing temperature across the visible and infrared spectrum. In this work, I introduce Spectroscopic Ellipsometry (SE) to analyze dielectric constants of films and measure its thickness at multiple incident angles in visible and near-Infrared (IR) wavelengths both at room temperature and elevated temperatures. Using ellipsometry, several single and multilayer thin films (CeO2 and other transparent materials-based) have been measured their dielectric constants and thickness at room temperature and high temperature up to 500°C using thermal control stages called INSTEC. The change of their optical properties with temperatures has been characterized using theoretical modelling. Fitting their optical properties have been observed by changing thickness of each layer and calculating the corresponding Cauchy parameters in transparent material. Finally, FTIR measurements will be used to further characterize direct emission of these films at higher temperatures. This will be performed at room temperature and high temperature up to 1400 °C.</div>

No description available.

The master's thesis deals with experimental study of tribological characteristics of smart fluids. Smart fluids are substances in liquid state reacting to the presence of magnetic or electric field by change in rheological properties. For possible application in devices using conventional lubricants is necessary to choose suitable smart fluid and study the influence of excitation on formation of lubricating layer, friction and wear. Comprehensive description of excitation influence is executed using three experimental devices and theoretical model for measurements parameters specification. Assessed are lubricant film thickness, friction coefficient and wear under smart fluid activation in non-conformal contact. Results show significant observable influence of smart fluids excitation on all assessed aspects. Understanding the mechanisms of smart fluids excitation can be a key step in development of intelligent devices with active external control of lubricant behaviour and character, that could lead to maintenance cost reduction and effectivity improvement.