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Author: Mittwoch, K. ×

Publications Search Results

Now showing 1 - 2 of 2
  • Publication
    Fresnoite thin films grown by pulsed laser deposition: Photoluminescence and laser crystallization
    ( 2011)
    Müller, A.
    ;
    Lorenz, M.
    ;
    Brachwitz, K.
    ;
    Lenzner, J.
    ;
    Mittwoch, K.
    ;
    Skorupa, W.
    ;
    Grundmann, M.
    ;
    Höche, T.
    Fresnoite (Ba2TiSi2O8-BTS) thin films were grown on fused quartz, silicon (100), MgO (100), and a-plane sapphire by pulsed laser deposition, and crystallized by subsequent thermal or flash lamp annealing. The corresponding texture evolution of the BTS thin films was studied by X-ray diffraction. The preferential (001) texture of the crystallised BTS films was found to be most pronounced on sapphire substrates. The broad photoluminescence band of the BTS thin films depends only weakly on temperature. The intensity of the BTS luminescence can be as high as that of the most efficient oxide scintillator materials. In order to qualify the fresnoite thin films for photonic applications, we demonstrate infrared-laser direct writing in amorphous BTS films which allows a local crystallisation and patterning. A subsequent considerable enhancement of luminescence intensity can be applied for UV-sensitive marking of nearly any object.
  • Publication
    Laser patterning of thin films for luminescence applications
    ( 2011)
    Höche, T.
    ;
    Lorenz, M.
    ;
    Müller, A.
    ;
    Grundmann, M.
    ;
    Mittwoch, K.
    Fresnoite, Ba 2TiSi 2O 8, possesses a very intense and broad photoluminescence band similar to that of the most intense oxide scintillator materials. As such, fresnoite is to be considered a well-suited material for photonics applications, including phosphors. Complete miscibility with the isotypic fresnoite compounds Ba 2TiGe 2O 8 and Sr 2TiSi 2O 8 as well as doping with rare-earth ions facilitates colour-space design. In order to qualify fresnoite as a material for photonic applications, fresnoite thin films were synthesized on a-plane sapphire, upon which, in comparison to growth on silicon (100), quartz, and MgO (100), the texture is most pronounced. Infrared-laser direct writing in amorphous fresnoitic films on sapphire allows a spatially resolved crystallization and an enhancement of the luminescence intensity by about three orders of magnitude. The latter fact can be utilized for UV-sensitive marking and wavelength converters.