2, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Nanostructures, self-organized into periodic concentration modulations, have been reported with radically different two-phase morphologies, including vertical and lateral striations. In order to understand the origin of these morphologies, we study the organizing mechanisms of these architectures via phase decomposition during elevated temperature co-sputtering of immiscible metals such as Cu-Mo using analytical electron microscopy. Based on structural and chemical analysis results, an evolution in self-organized, nano-metallic morphologies was observed according to the direction of phase separation. This was the result of the phase separation kinetics relative to the deposition rate during growth. Depending on the comparison between the rate of phase separation and the deposition rate, novel lateral, vertical, and randomly oriented concentration modulations in three-dimensions were obtained. A predictive capability of these self-organizing nano-architectures will allow for synthesis by design for advanced functionalities.