MAX-phase materials are a new type of material class. These materials are potentiallyt echnologically important as they show unique physical properties due to the combination of metals and ceramics. In this project, spectroscopic ellipsometry in the spectral range of 0.06 eV –6.0 eV was used to probe the linear optical response of MAX-phases in terms of the complexd dielectric function ε(ω) = ε1(ω) + iε2(ω). Measured data were fit to theoretical models using the Lorentz and generalized oscillator models. Data from seven different samples of MAX-phase materials were obtained using two ellipsometers. Each sample dielectric function was determined, including their infrared spectrum.

Previous studies of protein adsorption on silicon have been restricted by the choice of a simple structure or large surface for protein to adsorb on. The aim of this project was to develop an optical model for more complex nanostructures in form of trenches etched in silicon and then examine if a protein would adsorb to the surface. The method used was infrared ellipsometry. The experimental values from measurements on the sample were used to develop an optical model that represent the nanostructure. A three-layered biaxial model proved to be accurate. One sample was then exposed to the protein albumin and then measured upon again. The results before and after protein adsorption were compared and a small optical signature was found were it could be expected for this specific protein. This shows that it is possible to detect adsorption in a complex nanostructure and to develop an accurate optical model for said structure.

Lead-tin telluride alloy, Pb1-xSnxTe, is a narrow band gap group IV–VI semiconductor with NaCl-like crystalline structure. This material has interesting electronic properties, which makes it suitable for designing infrared photo detectors, diode lasers, and thermo-photovoltaic energy converters. In this project, we used spectroscopic ellipsometry in the spectral range of 0.74–6.5 eV to probe the linear optical response of Pb1-xSnxTe alloys in terms of the complex dielectric function. A strong optical response in the range of 0.7-2.0 eV arising from optical absorption was found. We studied eleven different samples of Pb1-xSnxTe of p-type origin with x values in the range (0 ≤ x ≤ 1). They were prepared by means of molecular beam epitaxy (MBE) on BaF2 substrates with 15mm2 area.

Ellipsometry is an optical technique used for studies of thin films and surfaces. The technique is based on measurement and analysis of the changes in the state of polarization that occur when polarized light is reflected on a sample surface. The multichannel Mueller matrix ellipsometer is a new system that is about to enter the commercial market. It can measure the full 4x4 Mueller matrix of a sample. The Laboratory of Applied Optics at the Department of Physics, Chemistry and Biology at Linköpings University has purchased one such multichannel Mueller matrix ellipsometer, called RC2, from J.A. Woollam Co., Inc. This project has the objective to investigate potentials and limitations of this new ellipsometer. This is done by comparing measurements carried out on RC2 with similar measurements made on a different, well known ellipsometer system, the VASE ellipsometer. A study of the theoretical background of ellipsometry has been made including a description of the Jones formalism of describing optical properties as well as the Stokes/ Mueller formalism. A short theoretical description of the RC2 principles, in order to better understand the new ellipsometer is also given. Measurements have been made on samples of varying complexity, including isotropic and anisotropic samples with in-plane anisotropy and out-of-plane anisotropy. On samples with no depolarization there should be no difference between the two ellipsometers. As can be seen in the experimental results there is some difference, but very little. Both for the isotropic samples, where Δ and ψ have been measured, and anisotropic, where the full Mueller matrix has been measured, we find a good match between VASE and RC2. When the samples are depolarizing, we expect to see a difference in the Mueller matrix. We do notice a significant difference in the measurements on tilted nanometer rods of TiO2, which has an advanced nano-structure in the upper layer. We can thus conclude that samples with depolarizing properties reveal this when measured with the new RC2 ellipsometer.

In the past several years, epitaxial graphene on silicon carbide has been transformed from an academic curiosity of social scientists to a leading candidate material to replace silicon in post-CMOS electronics. This has come with rapid development of growth technologies, improved understanding of epitaxial graphene on the polar faces of silicon carbide, and new device fabrication techniques. The contributions of this thesis include refinement and improved understanding of graphene growth on the silicon- and carbon-faces in the context of managed local silicon partial pressure, high-throughput epitaxial graphene thickness measurement and uniformity characterization by ellipsometry, observations of nearly ideal graphene band structures on rotationally stacked carbon-face multilayer epitaxial graphene, presentation of initial experiments on localized in situ chemical modification of epitaxial graphene for an alternate path to semiconducting behavior, and novel device fabrication methods to exploit the crystal structure of the silicon carbide substrate. The latter is a particularly exciting foray into three dimensional patterning of the substrate that may eliminate the critical problem of edge roughness in graphene nanoribbons.

No description available.

<p>Previous studies of protein adsorption on silicon have been restricted by the choice of a simple structure or large surface for protein to adsorb on. The aim of this project was to develop an optical model for more complex nanostructures in form of trenches etched in silicon and then examine if a protein would adsorb to the surface. The method used was infrared ellipsometry. The experimental values from measurements on the sample were used to develop an optical model that represent the nanostructure. A three-layered biaxial model proved to be accurate. One sample was then exposed to the protein albumin and then measured upon again. The results before and after protein adsorption were compared and a small optical signature was found were it could be expected for this specific protein. This shows that it is possible to detect adsorption in a complex nanostructure and to develop an accurate optical model for said structure.</p>

<p>Lead-tin telluride alloy, Pb1-xSnxTe, is a narrow band gap group IV–VI semiconductor with NaCl-like crystalline structure. This material has interesting electronic properties, which makes it suitable for designing infrared photo detectors, diode lasers, and thermo-photovoltaic energy converters. In this project, we used spectroscopic ellipsometry in the spectral range of 0.74–6.5 eV to probe the linear optical response of Pb1-xSnxTe alloys in terms of the complex dielectric function. A strong optical response in the range of 0.7-2.0 eV arising from optical absorption was found. We studied eleven different samples of Pb1-xSnxTe of p-type origin with x values in the range (0 ≤ x ≤ 1). They were prepared by means of molecular beam epitaxy (MBE) on BaF2 substrates with 15mm2 area.</p>

<p>Ellipsometry is an optical technique used for studies of thin films and surfaces. The technique is based on measurement and analysis of the changes in the state of polarization that occur when polarized light is reflected on a sample surface.</p><p>The multichannel Mueller matrix ellipsometer is a new system that is about to enter the commercial market. It can measure the full 4x4 Mueller matrix of a sample.</p><p>The Laboratory of Applied Optics at the Department of Physics, Chemistry and Biology at Linköpings University has purchased one such multichannel Mueller matrix ellipsometer, called RC2, from J.A. Woollam Co., Inc.</p><p>This project has the objective to investigate potentials and limitations of this new ellipsometer. This is done by comparing measurements carried out on RC2 with similar measurements made on a different, well known ellipsometer system, the VASE ellipsometer.</p><p>A study of the theoretical background of ellipsometry has been made including a description of the Jones formalism of describing optical properties as well as the Stokes/ Mueller formalism.</p><p>A short theoretical description of the RC2 principles, in order to better understand the new ellipsometer is also given.</p><p>Measurements have been made on samples of varying complexity, including isotropic and anisotropic samples with in-plane anisotropy and out-of-plane anisotropy.</p><p>On samples with no depolarization there should be no difference between the two ellipsometers. As can be seen in the experimental results there is some difference, but very little. Both for the isotropic samples, where Δ and ψ have been measured, and anisotropic, where the full Mueller matrix has been measured, we find a good match between VASE and RC2.</p><p>When the samples are depolarizing, we expect to see a difference in the Mueller matrix. We do notice a significant difference in the measurements on tilted nanometer rods of TiO2, which has an advanced nano-structure in the upper layer. We can thus conclude that samples with depolarizing properties reveal this when measured with the new RC2 ellipsometer.</p>

Tirta ErMnO3 optinės savybės: apskaičiuotos dielektrinių skvarbų spektrinės priklausomybės, optinių šuolių energijos, lūžio ir sugerties rodikliai. Tyrimai atlikti elipsometru, dielektrinė funkcija apskaičiuojama pagal vienašio kristalo modelį. / Manganites have attracted a lot of attention due to their magnetical properties: colossal magnetoresistance, variety of phase, but the optical properties of ErMnO3 were not widely investigated. Investigation of optical properties of ErMnO3 single crystal were studie by means of ellipsometry method. Ellipsometric studies have been carried out in the spectral range of 1- 5 eV. The photimetric ellipsometer with rotating analyzer was used. Experimental ellipsometer data were analysed in the isotropical and uniaxial crystal models. The optical properties of ErMnO3 were investigated: ellipsometric parameters Ψ and Δ were determinated, the components of dielectric function and energy of optical transition were found, calculated refractive and absorption indexs.