Alexander Kompch

Publications (2)1.37 Total impact

• Article: Chemical vapor synthesis of nanocrystalline perovskites using laser flash evaporation of low volatility solid precursors.

  Markus Winterer, Vladimir V Srdic, Ruzica Djenadic, Alexander Kompch, Thomas E Weirich
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  ABSTRACT: One key requirement for the production of multinary oxide films by chemical vapor deposition (CVD) or nanocrystalline multinary oxides particles by chemical vapor synthesis (CVS) is the availability of precursors with high vapor pressure. This is especially the case for CVS where much higher production rates are required compared to thin films prepared by CVD. However, elements, which form low valent cations such as alkaline earth metals, are typically only available as solid precursors of low volatility, e.g., in form of beta-diketonates. This study describes laser flash evaporation as precursor delivery method for CVS of nanocrystalline perovskites. Laser flash evaporation exploits the nonequilibrium evaporation of solid metal organic precursors of low vapor pressure by absorption of the infrared radiation of a CO(2) laser. It is shown that stoichiometric, nanocrystalline particles consisting of SrZrO(3) and SrTiO(3) can be formed from corresponding mixtures of beta-diketonates which are evaporated nonselectively and with high rates by laser flash evaporation.
  Review of Scientific Instruments 01/2008; 78(12):123903. · 1.37 Impact Factor
• Article: Chemical vapor synthesis and characterization of chromium doped zinc oxide nanoparticles

  Wei Jin, In-Kyum Lee, Alexander Kompch, Udo Dörfler, Markus Winterer
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  ABSTRACT: ZnO and Cr doped ZnO nanoparticles were synthesized by chemical vapor synthesis (CVS) which is a modified chemical vapor deposition (CVD) process. The resulting powders consist of nanocrystalline particles and were characterized by X-ray diffraction (XRD), nitrogen adsorption (BET), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), element analysis, and extended X-ray absorption fine structure (EXAFS) spectroscopy. The grain size decreases with increasing dopant concentration. The lattice constants extracted by the Rietveld method from XRD data vary slightly with doping concentration. XRD and EXAFS data analysis show that the Chromium dopant atoms are incorporated into the wurtzite host lattice.
  Journal of the European Ceramic Society.