On the Competition Between the Phenomena Involved in the Aerosol Dynamics in Sputtering Nonequilibrium Plasma

We made use of a combination of three models that describe plasma equilibrium, cluster kinetics, and aerosol dynamics in order to investigate solid carbonaceous dust formation in a dc gas discharge where the carbon source is provided by a graphite cathode sputtering. This enabled us to determine the time evolution of some of the particle characteristics, e.g., total density, mean diameter, and average charge, as a function of the sputtering yield. We showed that for a few minutes of discharge duration, the particle density reaches 10
⁷
-10
⁸
cm
^-3
, the particle mean diameter is approximately 40 nm and the particle size distributions are bimodal for all the investigated conditions. We also showed that the variation of the sputtering yield affects in a quite unexpected way the interplay between the phenomena involved in the aerosol dynamics. Basically, larger sputtering yields result in larger density and coagulation rate on one hand, and in a limited nucleation and surface sticking kinetics on the other hand.