Nanocluster interfaces and epitaxy: Ag on Si surfaces

We summarize our experimental investigation of the morphology and orientation of Ag nanoclusters on silicon surfaces formed by room-temperature (RT) deposition and subsequent annealing. Using Ag as a model system, we show that nanocluster interfaces and epitaxy depend critically on the cluster size and the substrate lattice. In case of Ag on hydrogen-terminated Si (111), the RT self-assembled clusters grow as mostly single-crystal crystallites with Ag (111)//Si (111), but the in-plane orientation has a dispersion of ∼ 9° centering at Si [110] direction. Upon annealing, the Ag clusters drastically rotated to the epitaxial configuration with the in-plane orientation aligned to the Ag [110]//Si [110] direction. The rotation and epitaxy of the Ag nanoclusters are explained based on a coincident site lattice model and interface energy minimization.