Plasma Chemistry and Plasma Processing

, Volume 15, Issue 4, pp 581–606

Nanoparticle formation using a plasma expansion process

  • N. Rao
  • S. Girshick
  • J. Heberlein
  • P. McMurry
  • S. Jones
  • D. Hansen
  • B. Micheel
Article

DOI: 10.1007/BF01447062

Cite this article as:
Rao, N., Girshick, S., Heberlein, J. et al. Plasma Chem Plasma Process (1995) 15: 581. doi:10.1007/BF01447062

Abstract

We describe a process in which nanosize particles with u narrow size distribution are generated by expanding a thermal plasma carrying vapor-phase precursors through a nozzle. The plasma temperature and velocity profiles are characterized by enthalpy probe measurements. by calorimetric energy balances. and by a model of the nozzle flow. Aerosol samples are extracted from the flow downstream of the nozzle by means of a capillary probe interfaced to a two-stage ejection diluter. The diluted aerosol is directed to a scanning electrical mobility spectrometer (SEMS) which provides on-line size distributions down to particle diameters of 4 nmt. We have generated silicon, carbon, and silicon carbide particles with number mean diameters of about 10 not or less, and we have obtained some correlations between the product and the operating conditions. Inspection of the size distributions obtained in the experiments, together with the modeling results, suggests that under our conditions silicon carbide formation is initiated by nucleation of extremely small silicon particles from supersaturated silicon vapor, followed by chemical reactions at the particle surfaces involving carbon-containing species from the gas phase.

Key words

Nanoparticles plasma synthesis DC arc plasma diagnostics nucleation silicon: silicon carbide. 

Copyright information

© Plenum Publishing Corporation 1995

Authors and Affiliations

  • N. Rao
    • 1
  • S. Girshick
    • 1
  • J. Heberlein
    • 1
  • P. McMurry
    • 1
  • S. Jones
    • 1
  • D. Hansen
    • 1
  • B. Micheel
    • 1
  1. 1.University of MinnesotaMinneapolis