Evaporation of Gold on NaCl Surfaces as a Way to Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Herein, the growth of Au nanoparticles on NaCl surfaces as a way to control their spatial distribution is explored, giving new insights into the shape and relative orientation of the resulting nanoparticles through modern electron microscopy techniques. Their morphological features depending on the geometry of the NaCl surface site they nucleated on are described in detail. Also, hitherto unreported small but systematic angular deviations in the range of 1-4° from the exact epitaxial orientation were observed. A theoretical approach based on straightforward elastic energy considerations and yet capable of accounting for the experimental results was developed. The production of metallic nanoparticles is a fundamental subject in the development of nanotechnology, and the fine control of the shape and spatial distribution is an important issue for the applicability of nanoparticles. Furthermore, in spite of the extensive research on this topic, some key features such as the precise mechanism controlling particle shape and particle-substrate orientation are still not well understood as evidenced by the results of this work. Thus, a clear understanding of the role played by the diverse factors involved in epitaxial growth is required to produce nanoparticles with finely tailored properties.