TY - JOUR A1 - Lux, Helge A1 - Edling, Matthias A1 - Lucci, Massimiliano A1 - Kitzmann, Julia A1 - Villringer, Claus A1 - Siemroth, Peter A1 - De Matteis, Fabio A1 - Schrader, Sigurd T1 - The Role of Substrate Temperature and Magnetic Filtering for DLC by Cathodic Arc Evaporation JF - Coatings N2 - Diamond-like carbon (DLC) films were deposited using two different types of high current arc evaporation. The first process used a magnetic particle filter to remove droplets from the plasma. For the second process, the samples were put into a metallic cage which was placed directly above the plasma source. For both processes, we varied the substrate temperature from 21 to 350 °C in order to investigate the temperature effect. The samples were characterized using SEM, AFM, XPS, Raman Spectroscopy, Ellipsometry, Photometry, and Nano Indentation in order to compare both methods of deposition and provide a careful characterization of such DLC films. We found that the sp3 content and the hardness can be precisely adjusted by changing the substrate temperature. Furthermore, in the case of unfiltered deposition, the optical constants can be shifted in the direction of higher absorbance in order to produce black and hard carbon coatings. KW - DLC KW - ta-C KW - arc evaporation KW - substrate temperature KW - hardness KW - optical constant KW - ellipsometry Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12295 SN - 2079-6412 VL - 9 IS - 5 SP - 345 ER - TY - JOUR A1 - Sopinskyy, Mykola A1 - Grytsenko, Kostyantyn A1 - Villringer, Claus A1 - Kolomzarov, Yurii A1 - Schrader, Sigurd T1 - Determination of scattering and Urbach absorption contributions to the light extinction in PTFE films by using graphical representation technique and numerical solution of the inverse problem JF - Semiconductor Physics, Quantum Electronics & Optoelectronics N2 - Ellipsometrically obtained spectral dependences of ordinary αxy and extra-ordinary αz extinction/attenuation coefficients within the spectral range λ = 300…980 nm of uniaxially anisotropic polytetrafluoroethylene (PTFE) films were analyzed. We considered the capabilities and specific features of the graphical representation technique for determining the contribution of Rayleigh scattering and Urbach absorption to light attenuation in the spectral range beyond fundamental absorption. It has been shown that the graphical approach enables to estimate these contributions qualitatively, semi-quantitatively or quantitatively, depending on the situation. The conclusions made using the analysis of graphical representation are confirmed by numerical solution of the inverse problem via simulation of the αxy (λ), αz (λ) experimental dependences within the framework of a best-fit procedure. Being based on both of these approaches, we have ascertained that, in the as-prepared PTFE films, the so-called anomalous light scattering (ALS) with the spectral dependence of scattering coefficient αs ≈ as λ–p (p > 4) takes place. Transformation of scattering from ALS to the Rayleigh one with p ≈ 4 due to annealing is accompanied by an increase of Urbach (subband) absorption. Both of these factors cause narrowing the dynamic range of extinction coefficient values. Both scattering and absorption coefficients are higher for the component of light polarized along the normal to the substrate as compared to the component polarized in parallel to it. The relationship between observed behavior of the scattering and absorption coefficients and the film structure has been discussed. KW - Rayleigh scattering KW - Urbach tail KW - absorption coefficient KW - scattering coefficient KW - graphical method KW - ellipsometry KW - polytetrafluoroethylene Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-18035 SN - 1605-6582 VL - 26 IS - 3 SP - 303 EP - 314 PB - National Academy of Sciences of Ukraine. Institute for Semiconductor Physics CY - Kyiv ER -