Energy autonomous wearable sensors for smart healthcare: a review

Energy Autonomous Wearable Sensors (EAWS) have attracted a large interest due to their potential to provide reliable measurements and continuous bioelectric signals, which help to reduce health risk factors early on, ongoing assessment for disease prevention, and maintaining optimum, lifelong health quality. This review paper presents recent developments and state-of-the-art research related to three critical elements that enable an EAWS. The first element is wearable sensors, which monitor human body physiological signals and activities. Emphasis is given on explaining different types of transduction mechanisms presented, and emerging materials and fabrication techniques. The second element is the flexible and wearable energy storage device to drive low-power electronics and the software needed for automatic detection of unstable physiological parameters. The third is the flexible and stretchable energy harvesting module to recharge batteries for continuous operation of wearable sensors. We conclude by discussing some of the technical challenges in realizing energy-autonomous wearable sensing technologies and possible solutions for overcoming them

Analyse des nouveaux matériaux photovoltaïques obtenus en coulée continue

Thèse sous la direction de M. Loghmarti et J.C. Muller soutenue le 10 juin 2002 - Université Louis Pasteur (Strasbourg I) - Laboratoire PHASE (PHysique et Applications des SEmi-conducteurs, UPR 292

Microwave plasma assisted process for cleaning and deposition in future semiconductor technology

The epitaxial growth of silicon layers is an important step in the fabrication of semiconductor devices. For conventional silicon epitaxy, high temperatures, up to 900 °C are necessary. However, in future, semiconductor technology epitaxy processes at lower temperatures are required to increase the integration density. The goal of this study was to investigate microwave plasma assisted processes for the selective removing of thin silicon oxide, the cleaning of silicon surfaces and the depositing of high quality silicon films. The main focus was to apply these processes for low temperature epitaxy. All processes, such as oxide removal, cleaning and deposition, were done in one chamber and with microwave plasma assistance. In order to remove silicon dioxide, the etching behavior of hydrogen, fluorine, and hydrogen/fluorine plasma was studied. It was shown, that with hydrogen/fluorine plasma, the best selectivity of oxide to silicon was reached. The deposition process of silicon was studied by growing μc-Si films. The process was characterized and optimized by spectral ellipsometry. After a successful characterization of all process steps, silicon epitaxy layers have been grown with in-situ removal of native oxide and in-situ surface cleaning. The temperature for all process steps was reduced below 450 °C

Thin film multilayer design types for colored glazed thermal solar collectors

Multilayered inteference filters of dielectric thin films have been designed for the application as energy-efficient coloration of collector cover glasses. The optical behavior of the designed multilayers is analyzed by computer simulations yielding the CIE color coordinates, the relative luminosity, the degree of solar transmission, and a figure of merit which is a measure for the energy effectiveness of the coloration. A high performance should be achieved with a number of individual layers reasonable for large-scale deposition. Constraints on the refractive index of the dielectric films are given by the availability of suitable thin film materials. The challenge lies in finding the best combination of material choice and layer thicknesses. We describe several type of multilayer designs for which the computer simulations yield promising results