In situ growth of superconducting YBa2Cu3O7-δ thin films on Si with conducting indium-tin-oxide buffer layers

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Different methods to adjust the wetting behavior of surfaces of the UV-curable adhesive NOA81 were investigated and quantitatively characterized by dynamic contact angle measurements with an optical goniometer. A new method to make NOA81 surfaces hydrophobic by mixing an additive in the uncured polymer was presented. The effect was confirmed by surface roughness studies using atomic force microscopy and X-ray photoelectron spectroscopy measurements. The chemical resistance of NOA81 microfluidic channels was

The requirements for a micromorph tandem cell front transparent conductive oxide (TCO) are multiple. This essential layer needs a high transparency, excellent conduction, strong light scattering into silicon and good surface morphology for the subsequent growth of silicon cells. These parameters are all linked and trade-offs have to be found for optimal layer. The optimum combination, taking into account current achievable materials properties, is still unclear. Concerning transparency, we study here the im

The performances of thin film silicon solar cells are reported for the use of increasingly rough zinc-oxide (ZnO) front electrodes. Experimental results show that textured substrates favor increased light trapping but also the local creation of undesired current drains, degrading the electrical performance of the cells. While an appropriate plasma treatment of the ZnO surface and a high silicon material quality are required to decrease the density of such current drains, doped nano-crystalline silicon oxide

Properties of thin films such as the crystallinity of silicon deposited from SiH4 - H-2 discharges are governed by the plasma composition. Therefore, it is crucial to measure the plasma composition in order to understand and optimize the deposition rate, deposition efficiency and material quality of thin film deposition, such as for microcrystalline silicon, which is a key material for silicon thin film photovoltaic solar cells. This task can be performed by using Fourier transform infrared absorption spect

The four-point probe is used for the measurement of the resistivity of thin metal or semiconductor films. There is an interest in miniaturization of the probes to obtain higher surface sensitivity, an increased spatial resolution and less damage to the sample. In this project the design, fabrication and first characterisation of a microscopic four-point device using SU-8-cantilevers were realized. A 200-µm-thick SU-8 body chip allows the handling of the device and the electrical connection to the measuremen

Although LTCC (low temperature co-fired ceramics) technology is an attractive solution for smart-packaging of micro-electronic devices, numerous studies are still underway to overcome the difficulties encountered during processing and application. These difficulties center on chemical and physical issues occurring between the LTCC components during firing. The chemical issues arise from the interaction of the glass phase(s) in the tape and the thick-films, whereas the physical issues are usually due to the

This thesis analyzes the properties of heavily doped nanocrystalline titanium dioxide. Thin films were deposited by magnetron sputtering with either water vapor as reactive gas or a periodically interrupted oxygen supply. The samples were at the same time electrically conducting and transparent. They consisted of mixtures of rutile, anatase and amorphous phases. Titanium dioxide is chemically stable, hard, non-toxic, transparent, and inexpensive. Due to a high refractive index it is often found in optical a

Electrochemical techniques were applied to a coulometric titration cell to study oxygen nonstoichiometry and transport in the perovskite-type oxide La0.4Ba0.6Fe0.8Co0.2O3-delta. Slow scan voltammetry (3mV/s) was used to obtain oxygen nonstoichiometry vs. the oxygen partial pressure (p(O2)) data. The voltammograms were further analysed using a simple defect model to yield the absolute value of the oxygen nonstoichiometry. Relaxation measurements were performed to obtain chemical diffusion and surface exchang

Zinc oxide (ZnO) is a material that belongs to the family of Transparent Conductives Oxides (TCO). Its non-toxicity and the abundant availability in the Earth's crust of its components make it an ideal candidate as electrical transparent contact for thin-film amorphous and/or microcrystalline silicon solar cells. The Low-Pressure Chemical Vapour Deposition (LP-CVD) method allows one to obtain rough ZnO layers, which can effectively scatter the light that passes through them. This high scattering capacity in

Angle-resolved photoemission spectroscopy reveals very surprising strain-induced effects on the electronic band dispersion of epitaxial La2-xSrxCuO4-delta thin films. In strained films we measure a band that crosses the Fermi level (E-F) well before the Brillouin zone boundary. This is in contrast to the flat band reported in unstrained single crystals and in our unstrained films, as well as in contrast to the band flattening predicted by band structure calculations for in-plane compressive strain. In spite

Pb(Zr-x, Ti1-x)O-3 (PZT) piezoelectric thin films are of major interest in MEMS technology for their ability to provide electro-mechanical coupling. In this work, the effective transverse piezoelectric coefficient e(31,f) of sol-gel processed films was investigated as a function of composition, film texture and film thickness. Dense, textured and crack-free PZT films have been obtained on silicon substrates up to a thickness of 4 mum. Crystallization anneals have been performed for every 0.25 mum. Nucleatio

A high order finite difference scheme is introduced to deal with thermo-hydraulic quench simulation in superconducting magnets, specifically in the case of cable-in-conduit conductors (CICC). Liquid helium flow in CICC is governed by the unsteady convection-diffusion conservation equations, in the low Mach number and high Reynolds number flow, region. In the past. several years many methods have been considered for quench simulation in superconducting magnets, for example, finite element, finite volume, and

In situ growth of superconducting YBa2Cu3O7-δ thin films on Si with conducting indium-tin-oxide buffer layers

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Norland optical adhesive (NOA81) microchannels with adjustable wetting behavior and high chemical resistance against a range of mid-infrared-transparent organic solvents

Transparent conducting oxide electrodes requirements for high efficiency micromorph solar cells

Low-conductivity doped layers for improved performance of thin film silicon solar cells on highly textured substrate

Plasma diagnostics as a tool for process optimization: the case of microcrystalline silicon deposition

Micro-Four-Point probe based on SU-8 cantilevers

Materials compatibility issues in LTCC technology and their effects on structural and electrical properties

Free carriers in nanocrystalline titanium dioxide thin films

Electrochemical characterisation of oxygen nonstoichiometry and transport in mixed conducting oxides : Application to La0.4Ba0.6Fe0.8Co0.2O3

L'oxyde de zinc par dépôt chimique en phase vapeur comme contact électrique transparent et diffuseur de lumière pour les cellules solaires

Strain and high temperature superconductivity: Unexpected results from direct electronic structure measurements in thin films

{100}-textured, piezoelectric Pb(Zr-x Ti1-x)O-3 thin films for MEMS: integration, deposition and properties

Quench simulation in superconducting cables using optimized DRP scheme