Molecular dynamics simulation on the deposition behavior of nanometer-sized Au clusters on a Au (001) surface

The deposition behavior of 300-1500 atom Au clusters was studied with molecular dynamics (MD) using a potential of the embedded atom method (EAM). This study was aimed at examining the possibility of thin-film growth by a cluster as a building unit, which had been suggested in the charged cluster model (CCM) (Hwang ct al., J. Crystal Growth 162 (1990) 55). According to the CCM, most of the commercially available thin films were actually cluster-assembled ones although they have been believed to grow by the atomic unit. Small (300 and 500 atoms) and large (1000 and 1500) clusters equilibrated at 1000 K were used as the starting points for the simulation. Small clusters melted during equilibration at 1000 K, while large clusters did not. Clusters of various sizes were deposited on a Au (1 0 0) surface thermostated at 800 K. Within 50 ps, the 300-atom cluster underwent full epitaxial recrystallization with the substrate surface. In contrast, a much longer time was required for the 1000- and 1500-atom clusters to achieve full epitaxial recrystallization. The epitaxial recrystallization behavior of small and large clusters used in this simulation Suggests the possibility of thin-film growth by a cluster unit as suggested in the CCM. (C) 2001 Published by Elsevier Science B.V.