Synthesis and In-situ Process analysis: CVS, AMS

Chemical Vapor Synthesis of Nanocrystalline Particles

modular_cvs

Chemical Vapor Synthesis (CVS) is a modified Chemical Vapor Deposition (CVD) method where the process parameters are adjusted to form nanoparticles instead of film. The entire range of reaction regimes and corresponding microstructures (epitaxial, polycrystalline, columnar, granular films and aerogel coatings as well as nanopowders) are shown in the below.

Both in CVD and CVS, precursors are metalorganics, carbonyls, hydrides, chlorides and other volatile compounds in gaseous, liquid or solid state. The major limitation of the CVS process is the availability of appropriate precursor materials. The energy for the conversion of the reactants into nanoparticles is supplied in hot wall (external furnace), flame (reaction enthalpy), plasma (microwave or radio frequency) and laser (photolysis or pyrolysis) reactors. Chemical Vapor Reaction (CVR), Chemical Vapor Condensation (CVC), Chemical Vapor Precipitation (CVP) are synonyma used frequently in the literature. The most important process parameters determining the quality and usability of the nanopowders are the total pressure (typical range from 100 to 100000 Pa), the precursor material (decomposition kinetics and ligands determining the impurity level), the partial pressure of the precursor (determining the production rate and particle size), the temperature or power of the energy source, the carrier gas (mass flow determining the residence time) and the reactor geometry. The nanoparticles are extracted from the aerosol by means of filters, thermophoretic collectors, electrostatic precipitators or scrubbing in a liquid. A typical laboratory reactor (shown schematically in the figure below) consists of a precursor delivery system, a reaction zone, a particle collector and a pumping system. Modifications of the precursor delivery system and the reaction zone allow the synthesis of pure oxides, doped oxides, coated nanoparticles, functionalized nanoparticles and granular films.

 

  • C. Schilling, and M. Winterer, Preserving Particle Characteristics at Increasing Production Rate of ZnO Nanoparticles by Chemical Vapor Synthesis, Chem. Vap. Dep. 20 (2014), 138-145
  • C. Schilling, R. Theissmann, C. Notthoff, and M. Winterer, Synthesis of Small Hollow ZnO Nanospheres from the Gas Phase, Particle & Particle Systems Charakterization 30 (2013), 434-437
  • C. Notthoff, C. Schilling, and M. Winterer, Gas temperature measurements inside a hot wall chemical vapor synthesis reactor, Review of Scientific Instruments 83/11 (2012), 114904
  • M. Ali, M. D. Donakowski, C. Mayer, and M. Winterer, Chemical vapor functionalization: a continuous production process for functionalized ZnO nanoparticles, Journal of Nanoparticle Research 14/3 (2012), 689
  • R. Djenadic and M. Winterer, chapter 2, Chemical Vapor Synthess of Nanocrystalline Oxides, in Axel Lorke, Markus Winterer, Roland Schmechel, und Christof Schulz (eds.), Nanoparticles from the Gas Phase – Formation, Structure, Properties, Springer Berlin 2012, ISBN 978-3-642-28546-2
  • R. Djenadic, G. Akgul, K. Attenkofer, and M. Winterer, Chemical Vapor Synthesis and Structural Characterization of Nanocrystalline Zn1-xCoxO (x=0-0.50) Particles by X-ray Diffraction and X-ray Absorption Spectroscopy, Journal of Physical Chemistry 114 (2010), 9207-9215
  • M. Ali, and M. Winterer, Influence of Nucleation Rate on the Yield of ZnO Nanocrystals Prepared by Chemical Vapor Synthesis, Journal of Physical Chemistry 114 (2010), 5721-5726
  • M. Ali, N. Friedenberger, M. Spasova, and M. Winterer, A Novel Approach for Chemical Vapor Synthesis of ZnO Nanocrystals: Optimization of Yield, Crystallinity; Chem. Vap. Dep. 15 (2009), 192-198
  • L. Schneider, S.V. Zaitsev, W. Jin, A. Kompch, M. Winterer, M. Acet, and G. Bacher, Fabrication and analysis of Cr-doped ZnO nanoparticles from the gas phase, Nanotechnology 20/13 (2009), 135604
  • W. Jin, I. K. Lee, A. Kompch, U. Dörfler, and M. Winterer, Chemical vapor synthesis and characterization of chromium doped zinc oxide nanoparticles, J. Eur. Ceram. Soc. 27 (2007), 4333-4337
  • J. U. Brehm, M. Winterer, and H. Hahn, Synthesis and local structure of doped nanocrystalline zinc oxides, J. Appl. Phys. 100 (2006), 064311
  • Th. Enz, M. Winterer, B. Stahl, S. Bhattacharya, G. Miehe, K. Foster, C. Fasel, and H. Hahn, Structure and Magnetic Properties of Iron Nanoparticles Stabilized in Carbon, Journal of Applied Physics 99 (2006), 044306
  • I. K. Lee and M. Winterer, Aerosol mass spectrometer for the in situ analysis of chemical vapor synthesis processes in hot wall reactors, Rev. Sci. Instr. 76 (2005), 095104-1/8
  • H. Sieger, M. Winterer, H. Mühlenweg, G. Michael, and H. Hahn, Controlling Surface Composition and Zeta Potential of Chemical Vapor Synthesized Alumina-Silica Nanoparticles, Chem. Vap. Dep. 10 (2004), 71-76
  • M. Winterer and H. Hahn, Nanoceramics by Chemical Vapor Synthesis, Z. Metallkd. 94 (2003), 1084-1090
  • M. Schallehn, M. Winterer, T. Weirich, U. Keiderling, H. Hahn, In-Situ Preparation of Polymer Coated Alumina Nanopowders by Chemical Vapor Synthesis, Chem. Vap. Dep. 9 (2003), 40-44
  • Markus Winterer, Nanocrystalline Ceramics – Synthesis and Structure, Springer, Heidelberg 2002, Springer Series in Materials Science, Volume 53, ISBN 3-540-43433-X
  • V. V. Srdic, M. Winterer, and H. Hahn, Nanocrystalline Zirconia Surface Doped with Alumina: Chemical Vapor Synthesis, Characterization and Properties, J. Am. Ceramic Soc. 84 (2001), 2771
  • S. Seifried, M. Winterer, H. Hahn, Nanocrystalline Titania Films and Particles by Chemical Vapor Synthesis, Chem. Vap. Dep. 6 (2000), 239
  • V. V. Srdic, M. Winterer, and H. Hahn, Sintering Behavior of Nanocrystalline Zirconia Doped with Alumina Prepared by Chemical Vapor Synthesis, J. Am. Ceram. Soc. 83 (2000), 1853
  • V. V. Srdic, M. Winterer, G. Miehe and H. Hahn, Different Zirconia-Alumina Nanopowders by Modifications of Chemical Vapor Synthesis, Nanostructured Materials 12 (1999), 95
  • V. V. Srdic, M. Winterer, and H. Hahn, Sintering Behavior of Nanocrystalline Zirconia Prepared by Chemical Vapor Synthesis, J. Am. Ceramic Soc. 83 (2000), 729
  • S. Klein, M. Winterer, and H. Hahn, Reduced-Pressure Chemical Vapor Synthesis of Nanocrystalline Silicon Carbide Powders, Chem. Vap. Deposition 4 (1998), 143