Controlling the size of copper nanoparticles produced by gas aggregation source by an auxiliary RF discharge

One of the factors that hamper the broader use of magnetron-based gas aggregation sources of nanoparticles is a relatively limited range of the sizes of produced nanoparticles (NPs). In this study, we introduce and investigate a novel strategy to overcome this limitation, based on the use of an auxiliary radio frequency (RF) plasma generated inside the aggregation chamber. As shown for the example of copper NPs, their mean size can be varied from 20 to 160 nm depending on the applied RF power. This is explained in terms of plasma-induced trapping of the NPs in the aggregation chamber and their effective heating, both of which promote the growth of NPs by agglomeration/sintering of initially small NPs, and at a lesser extent also by the attachment of adatoms not consumed during the initial phase of NPs’ formation.