Temperature dependence of the aggregation behavior of aluminum nanoparticles on liquid substrate

Aluminum (Al) nanoparticle aggregates have been fabricated by thermal evaporation method on silicone oil surfaces at different substrate temperatures. The average diameter and height of the Al nanoparticles, namely Φ avg and H avg, are of the order of 101 and 100 nm, respectively. As the substrate temperature T s increases from 293 to 393 K, to the first order of approximation, Φ avg increases exponentially and H avg increases quickly between 333 and 373 K. By transmission electron microscopy measurement, we find that the Al nanoparticles and their aggregates exhibit amorphous structure over the whole temperature range. A simple theoretical model is established to explain the coalescence process of the nanoparticles with T s.