Numerical study of nanodusty plasmas

Nanodusty plasmas are of increasing interest for a variety of applications. To achieve control over the properties of nanoparticles produced by low-pressure plasmas, it is important to understand the coupled nanoparticle-plasma behavior. In this work, the behavior of nanodusty plasmas is studied with the help of numerical models to provide us insight into the mechanisms that are important in controlling the behavior of the system.;The transport behavior of nanoparticles is modeled in a plasma reactor when the plasma is off, with the help of a Monte Carlo (MC) model. The MC model is able to predict the nanoparticle behavior under different force effects--diffusion, gas drag, and thermophoresis. It is shown that, depending on the nanoparticle size, temperature gradient and gas flow in the reactor can be varied to control nanoparticle transport and deposition on the substrate.;A self-consistent one-dimensional (1D) fluid model is used to study the spatiotemporal behavior of a nanodusty plasma. The key results of the model are: nucleation of nanoparticles in plasmas is not limited to a short burst but continues though the coagulation phase, and coagulation in a nanodusty plasma is important only when the image potential between large negatively-charged nanoparticles and small neutral particles is taken into account and nanoparticle nucleation continues through the coagulation phase. It is also found that, contrary to what is commonly believed, the contribution of coagulation, in comparison to that of surface growth, to nanoparticle growth in plasmas is very small for the conditions considered.;Finally, the effect of the plasma processing parameters---temperature, pressure, applied voltage, and gas flow---on a nanodusty plasma is also investigated with the help of the 1D model. It is shown that the influence of operating parameters on nanoparticle transport phenomena, in contrast to that on other physical aspects such as nanoparticle charging or coagulation, has the most effect on the behavior of nanoparticles in a plasma.