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Author: Edling, Matthias × Type: Article ×

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    The role of substrate temperature and magnetic filtering for DLC by cathodic arc evaporation
    (Basel : MDPI, 2019) Lux, Helge; Edling, Matthias; Lucci, Massimiliano; Kitzmann, Julia; Villringer, Claus; Siemroth, Peter; De Matteis, Fabio; Schrader, Sigurd
    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. © 2019 by the authors.
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    Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses
    (Washington, DC : OSA, 2020) Bauer, Joachim; Gutke, Marko; Heinrich, Friedhelm; Edling, Matthias; Stoycheva, Vesela; Kaltenbach, Alexander; Burkhardt, Martin; Gruenefeld, Martin; Gamp, Matthias; Gerhard, Christoph; Steglich, Patrick; Steffen, Sebastian; Herzog, Michael; Dreyer, Christian; Schrader, Sigurd
    In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses. © 2020 Optical Society of America.