Pinning of size-selected gold and nickel nanoclusters on graphite

Size-selected gold and nickel nanoclusters are of interest from an electronic, catalytic, and biological point of view. These applications require the deposition of the clusters on a surface, and a key challenge is to retain the cluster size. Here controlled energy impact is used to immobilize the size-selected clusters on the graphite surface at room temperature. The threshold energy for pinning of ionized AuN $(N=20--100)$ and NiN $(N=10--300)$ clusters, over the impact energy range 350--20000.3em0exeV, is shown by scanning tunneling microscopy to scale with the cluster mass. This behavior is consistent with a previous study of silver clusters and demonstrates the more general applicability of the cluster pinning model.