Ion Beam "Photography": Decoupling Nucleation and Growth of Metal Clusters in Glass

We demonstrate that room temperature MeV ion irradiation of a glass containing copper oxide initiates nucleation of pure Cu clusters via the inelastic "electronic" component of the ion energy loss, when the latter is above a threshold value. The clusters grow under subsequent thermal annealing, following Lifshitz-Slyozov-Wagner kinetics. The decoupling of nucleation and growth is analogous to that occurring in the photographic process. It allows total control over the cluster density, average size, and size distribution.