Adsorption of small NaCl clusters on surfaces of silicon nanostructures

摘要

We have studied possible adsorption geometries of neutral NaCl clusters on the disorderedsurface of a large silicon model tip used in non-contact atomic force microscopy. Vie minimahopping method was used to determine low energy model tip configurations as well as, groundstate geometries of isolated NaCl clusters. The combined system was treated withdensityfunctional theory. Alkali halides have proven to be strong structure seekers and tend to formhighly stable ground state configurations whenever possible. The favored adsorption geometryfor four Na and four Cl atoms was found to be an adsorption of four NaCl dimers due to theformation of Cl—Si bonds. However, for larger NaCl clusters, the increasing energy required todissociate the cluster into NaCl dimers suggests that adsorption of whole clusters in theirisolated ground state configuration is preferred.