Mechanism of the formation of metal nanoclusters during pulsed laser deposition

The geometrical structure of Au, Ni, Co and Cr nanoclusters self-assembled on NaCl and HOPG surfaces under pulsed laser deposition (PLD) has been experimentally investigated. The PLD technique is characterized by an extremely high instantaneous deposition rate. Unlike for the thermal evaporation (TE) process, formation of fractal nanoclusters under PLD conditions has been observed with scanning tunneling microscopy (STM). The driving mechanism for this phenomenon occurring at high deposition rate is thought to be the evolution of the initial interacting-adatom states in a system far from thermodynamic equilibrium. The obtained results can be explained by proposing a new mechanism of condensed phase formation under the conditions of strong deviation from thermodynamic equilibrium.