<p>During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring this new class of materials that also enable many new areas of electronics applications. In the organic electronics research field conducting organic molecules and polymers are synthesized and used in devices. The reason behind the success of conducting polymers is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low-cost production techniques to manufacture devices.</p><p>This thesis reviews and describes different aspects of the organic electronics, here focusing on electrochromic displays; device improvements, the study of degradation and also patterning technology for rational manufacturing processing. The color contrast in electrochromic displays based on conjugated polymers was increased with approximately a factor of two by adding an extra electrochromic polymer. It was found that electrochemical over-oxidation (ECO) limits the flexibility in choosing desired electrochromic materials. ECO is one of the main degradation mechanisms in electrochromic displays. ECO is an efficient and fast process to permanently reduce the electronic conductivity in polythiophenes. From this, a novel patterning process was developed, in which the films of polythiophenes can be patterned through local and controlled deactivation of the conductivity. The ECO has been combined with different patterning tools to enable the use of existing printing tools for manufacturing. In combination with screen-printing, low-cost and high volume roll-to-roll patterning was demonstrated, while together with photolithography, patterning down to 2 µm can be achieved. Systematic studies have shown that conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomena the effect of pH on the over-oxidation characteristics was studied. The results suggest that a part of the mechanism for over-oxidation depends on the OH– concentration of the electrolyte used.</p>

<p>En studie i hur känsligheten avtar från ytan hos biosensorer med höga frekvenser presenteras. Med ny teknologi som avancerade elektroakustiska tunnfilms komponenter, så kallade FBARs, blir tidigare outforskade områden som decay längden möjliga att studera.</p><p>För att undersöka hur frekvenssvaret och känsligheten påverkas av interaktioner långt ut från en sensoryta används proteinkemi. Ett protokoll har optimerats innehållande aktivering med EDC/NHS och fibrinogen för att säkerställa en jämn tjocklek och fördelning av ett adsorberat proteinlager över en yta.</p><p>Dessa ytor kontrollerades först med hjälp av ellipsometri och sedan i ett QCM instrument. Alla experiment med de högfrekventa FBAR sensorerna utfördes vid Ångströmslaboratoriet i Uppsala där pågående forskning inom området finns.</p><p>Resultaten bekräftar teorin om en avtagande känslighet i och med ett ökat avstånd från ytan. En experimentell genomförd och beräknad tjocklek för decay längden uppskattades som inte helt stämde överens med den teoretiskt beräknade.</p><p>En ny term föreslås då frekvenssvaret hos en biosensor planar ut. Detta är en effekt som sker vid dubbla tjockleken av den teoretisk beräknade tjockleken av decay längden och har fått namnet; detection length. Efter denna längd eller gräns observeras en inverterad signal som det än så länge inte finns någon förklaring till.</p> / <p>A study of the sensitivity decrease of biosensors working at high frequencies is presented. With new technology such as film bulk acoustic resonators (FBAR), issues like the decay length is no longer irrelevant theory but may cause limitation in the system as well as it offers new detection possibilities.</p><p>To investigate the frequency response and sensitivity, layer-on-layer construction chemistry was used. A protocol involving activation with EDC/NHS and coupling chemistry with fibrinogen was optimized to ensure accurate thickness and uniformly distribution of each layer over the surface.</p><p>Surfaces were characterized using null ellipsometry and the protocol was tested in a traditional quartz crystal microbalance (QCM). Experiments with the FBAR were preformed at the Ångström laboratory in Uppsala were there is ongoing research and development in FBAR technology.</p><p>The results confirmed the theory of decreasing frequency and sensitivity further out from the surface. An experimental and estimated thickness was calculated which to some extent correlates to the theoretically calculated decay length.</p><p>A new terminology is suggested when the frequency levels off. It occurs approximately at twice the distance and thickness of the theoretically calculated decay length and is given the name; detection length. Beyond the detection length an inverted signal is observed which cannot yet be explained for.</p>

A microphone has been used to measure the dynamic pressure inside a vacuum chamber during high power impulse magnetron sputtering with high enough time-resolution (~µs) to track the pressure change during the discharge pulse. An experimental measurement of the dynamic pressure is of interest since it would give information about gas depletion, which is believed to dramatically alter the plasma discharge characteristics. This investigation has shown that the magnitude of the pressure wave, which arises due to the gas depletion, corresponds to a 0.4 - 0.7Pa (3 - 5.5mTorr) pressure difference at a distance of 15cm from the target, with base pressures of 2 - 6mTorr for a peak current of 110A. It has also been shown that another pressure wave, about 250µs later, can be detected. Its explanation is suggested to be that the initial pressure wave is bouncing against the chamber walls and thereby causing another peak.

In this study silicon-germanium quantum dots grown on silicon have been investigated. The aim of the work was to find quantum dots suitable for use as a thermistor material. The quantum dots were produced at KTH, Stockholm, using a RPCVD reactor that is designed for industrial production. The techniques used to study the quantum dots were: HRSEM, AFM, HRXRD, FTPL, and Raman spectroscopy. Quantum dots have been produced in single and multilayer structures. As a result of this work a multilayer structure with 5 layers of quantum dots was produced with a theoretical temperature coefficient of resistance of 4.1 %/K.

<p>In this study silicon-germanium quantum dots grown on silicon have been investigated. The aim of the work was to find quantum dots suitable for use as a thermistor material. The quantum dots were produced at KTH, Stockholm, using a RPCVD reactor that is designed for industrial production.</p><p>The techniques used to study the quantum dots were: HRSEM, AFM, HRXRD, FTPL, and Raman spectroscopy. Quantum dots have been produced in single and multilayer structures.</p><p>As a result of this work a multilayer structure with 5 layers of quantum dots was produced with a theoretical temperature coefficient of resistance of 4.1 %/K.</p>

<p>In order to produce x-ray mirrors the Thin Film Physics group at IFM grows Cr/Sc multilayers, with a typical thickness of the individual layers in the range 5-20 Å, and with as many periods as possible (a few hundred).</p><p>The quality of the multilayer interfaces is crucial for their performance as mirrors. For thick layers poly-crystalline multilayers form with an interface quality that is too poor for the use as x-ray mirrors. For thinner layers, however, amorphous layers are formed with a much better quality of the interface.</p><p>The goal of this project was to understand the formation of amorphous multilayers. Unfortunately it is impossible with the present day's theoretical tools to determine the structure of amorph interfaces. It is also impossible to calculate the interface structure for elements with large mismatch in size.</p><p>So we have to construct interface models that are both simple and based on physical arguments.</p>

Abstract Today sheet metal forming is used to make a variety of mass production because it has a high production rate. One of the biggest concerns in sheet metal forming is wear of the tool in form of galling. Galling in sheet metal forming is characterised by an increased tool surface roughness, unstable friction in the forming process and undesirable scratches on the final products. Several ways of ranking materials resistance to galling exist today but only ASM G98 is standardised. Nevertheless, some different methods developed for ranking tool materials’ tendency to galling have also been developed. The aim of this thesis is to develop and improve the Uddeholm Tooling Tribo Test rig located at Uddeholm Tooling AB. The rig, which is a variation of cylinder-on-cylinder test equipment, was improved with a new tool holder, a utilization of the real sheet material counter face and a new data acquisition system and software. The galling was detected using scratches on the sheet, metallographic analysis of the material adhered on the tool specimen, monitoring of coefficient of friction and the standard deviation of the coefficient of friction. The obtained results show difficulties with ranking of tool materials in terms of galling resistance under non-lubricated conditions. The tool steels tested were SVERKER21 and UNIMAX. AISI304-10, DC04 and DOCOL1000DP sheets were used. Additionally a low friction coating of BalinitC on SVERKER21 was also included. All specimens of the tool steels showed signs of galling on every run, only the low friction coating showed a transition in behaviour of friction coefficient corresponding to galling initiation. The standard deviation of the coefficient of friction increased at low loads. A decrease of the test loads led to stability loss of the system detected by an increase in the standard deviation of the coefficient of friction. This might happen because the Kistler platform is originally designed for larger loads. Although, the test rig does not work properly in its present state, the concept looks promising.

En studie i hur känsligheten avtar från ytan hos biosensorer med höga frekvenser presenteras. Med ny teknologi som avancerade elektroakustiska tunnfilms komponenter, så kallade FBARs, blir tidigare outforskade områden som decay längden möjliga att studera. För att undersöka hur frekvenssvaret och känsligheten påverkas av interaktioner långt ut från en sensoryta används proteinkemi. Ett protokoll har optimerats innehållande aktivering med EDC/NHS och fibrinogen för att säkerställa en jämn tjocklek och fördelning av ett adsorberat proteinlager över en yta. Dessa ytor kontrollerades först med hjälp av ellipsometri och sedan i ett QCM instrument. Alla experiment med de högfrekventa FBAR sensorerna utfördes vid Ångströmslaboratoriet i Uppsala där pågående forskning inom området finns. Resultaten bekräftar teorin om en avtagande känslighet i och med ett ökat avstånd från ytan. En experimentell genomförd och beräknad tjocklek för decay längden uppskattades som inte helt stämde överens med den teoretiskt beräknade. En ny term föreslås då frekvenssvaret hos en biosensor planar ut. Detta är en effekt som sker vid dubbla tjockleken av den teoretisk beräknade tjockleken av decay längden och har fått namnet; detection length. Efter denna längd eller gräns observeras en inverterad signal som det än så länge inte finns någon förklaring till. / A study of the sensitivity decrease of biosensors working at high frequencies is presented. With new technology such as film bulk acoustic resonators (FBAR), issues like the decay length is no longer irrelevant theory but may cause limitation in the system as well as it offers new detection possibilities. To investigate the frequency response and sensitivity, layer-on-layer construction chemistry was used. A protocol involving activation with EDC/NHS and coupling chemistry with fibrinogen was optimized to ensure accurate thickness and uniformly distribution of each layer over the surface. Surfaces were characterized using null ellipsometry and the protocol was tested in a traditional quartz crystal microbalance (QCM). Experiments with the FBAR were preformed at the Ångström laboratory in Uppsala were there is ongoing research and development in FBAR technology. The results confirmed the theory of decreasing frequency and sensitivity further out from the surface. An experimental and estimated thickness was calculated which to some extent correlates to the theoretically calculated decay length. A new terminology is suggested when the frequency levels off. It occurs approximately at twice the distance and thickness of the theoretically calculated decay length and is given the name; detection length. Beyond the detection length an inverted signal is observed which cannot yet be explained for.

In order to produce x-ray mirrors the Thin Film Physics group at IFM grows Cr/Sc multilayers, with a typical thickness of the individual layers in the range 5-20 Å, and with as many periods as possible (a few hundred). The quality of the multilayer interfaces is crucial for their performance as mirrors. For thick layers poly-crystalline multilayers form with an interface quality that is too poor for the use as x-ray mirrors. For thinner layers, however, amorphous layers are formed with a much better quality of the interface. The goal of this project was to understand the formation of amorphous multilayers. Unfortunately it is impossible with the present day's theoretical tools to determine the structure of amorph interfaces. It is also impossible to calculate the interface structure for elements with large mismatch in size. So we have to construct interface models that are both simple and based on physical arguments.

Semiconductors and related low-dimensional nanostructures are extremely important in the modern world. They have been extensively studied and applied in industry/military areas such as ultraviolet optoelectronics, light emitting diodes, quantum-dot photodetectors and lasers. The knowledge of growth dynamics of semiconductor nanostructures by metalorganic chemical vapour deposition (MOCVD) is very important then. MOCVD, which is widely applied in industry, is a kind of chemical vapour deposition method of epitaxial growth for compound semiconductors. In this method, one or several of the precursors are metalorganics which contain the required elements for the deposit materials. Theoretical studies of growth mechanism by MOCVD from a realistic reactor dimension down to atomic dimensions can give fundamental guidelines to the experiment, optimize the growth conditions and improve the quality of the semiconductor-nanostructure-based devices. Two main types of study methods are applied in the present thesis in order to understand the growth dynamics of semiconductor nanostructures at the atomic level: (1) Kinetic Monte Carlo method which was adopted to simulate film growths such as diamond, Si, GaAs and InP using the chemical vapor deposition method; (2) Computational fluid dynamics method to study the distribution of species and temperature in the reactor dimension. The strain energy is introduced by short-range valence-force-field method in order to study the growth process of the hetero epitaxy. The Monte Carlo studies show that the GaN film grows on GaN substrate in a two-dimensional step mode because there is no strain over the surface during homoepitaxial growth. However, the growth of self-assembled GaSb quantum dots (QDs) on GaAs substrate follows strain-induced Stranski-Krastanov mode. The formation of GaSb nanostructures such as nanostrips and nanorings could be determined by the geometries of the initial seeds on the surface. Furthermore, the growth rate and aspect ratio of the GaSb QD are largely determined by the strain field distribution on the growth surface. / QC 20100713