Thin Solid Films, Vol.345, No.1, 34-37, 1999
Molecular dynamics study of cluster deposition in thermal plasma flash evaporation
We simulated the rearrangement process of a high-temperature cluster put on a low-temperature substrate using molecular dynamics to verify the rearrangement behavior of the hot clusters. In the first step, a monoatomic homogeneous system wets simulated. A spherical fee stacked cluster consisting of 418 atoms corresponding to a 2 nm cluster, was placed on the 6 planes of a fee ( 1 1 1) substrate. The interaction potential was assumed to be the Morse function corresponding to a material with a melting point of 1680 K. The substrate temperature T-sub and the initial cluster temperature T-cluster(init) were varied from 300 to 1000 K and from 1450 to 3000 K, respectively. In the case of T-cluster(init) < 2100 K, the degree of cluster rearrangement is slight. Even at T-sub = 1000 K, the final structure was a six atomic-layer-high cap-like structure. On the other hand, clusters with T-cluster(init) > 2400 K rearranged markedly into almost two-dimensional clusters even at T-sub = 300 It and the degree of rearrangement seemed to be independent of the substrate temperature. It was revealed that high temperature nanoscale clusters could deform easily even on a room-temperature substrate owing to their high internal energy. This was confirmed by scanning tunneling microscopy,
Keywords:FILMS