TEMPERATURE EFFECT ON MICROSTRUCTURE AND AGGREGATION BEHAVIOR OF GOLD ATOMIC AGGREGATES ON SILICONE OIL SURFACE

Abstract

By thermal evaporation method, gold (Au) atomic aggregates were fabricated on a silicone oil surface and the aggregation mechanism was investigated. It is found that the apparent surface coverage ([Formula: see text]) of the Au aggregates dropped obviously, from 15% to 12% as the oil temperature (T) increased from 285[Formula: see text]K to 353[Formula: see text]K. Meanwhile, the average width of the aggregates gradually increased from 0.36[Formula: see text][Formula: see text]m to 0.50[Formula: see text][Formula: see text]m, indicating the aggregates combine with each other as T increased. By the atomic force microscopy observation, Au nanoparticles with diameter around 45.0 nm were observed in the aggregates, which were independent with T. Similarly, the average height of the aggregates found remain unchanged at around 10.0[Formula: see text]nm as T increased. The anomalous aggregation mechanism of Au aggregates suggests that a compact microstructure for Au aggregates is preferred at high T rather than three-dimensional (3D) growth, which is quite different from that of Ag aggregates.