Generation and post modification of nanoparticles by plasmas
Generation, deposition and functionalization of nanoparticles (NPs) have received much numerous attention during the last decades due to the outstanding features of NPs and their unique roles in adjusting different properties of advanced materials. This dissertation includes three individual projects focused on synthesis and modification of different NPs based on using plasmas. Finding correlations between the plasma parameters and the observed phenomena is very crucial in this study. Particularly, we investigate metal and oxide-metal NP formation by a gas aggregation source (GAS) combined with conventional DC and/or pulsed DC magnetron sputtering. The next part of this dissertation is focused on the plasma characterization of a hollow electrode discharge and the influence of the ignited discharge, in radio frequency (RF) regime, on metal NPs. It is demonstrated that the ignited discharge can significantly change the characteristics of the passing NP beam by charging metal NPs and redistributing them in the beam. The last part of this research is devoted to study the synthesis of germanium (Ge) NPs in a nonthermal plasma reactor. It is shown that by adjusting the gas composition, and consequently varying the dominant mechanisms in the plasma, the size, crystallinity and surface chemistry of the synthesized Ge NPs can be controlled.