Submonolayer-deposition of mass-selected Au+ and Au-n(+) (n = 3 and 7) on HOPG and amorphous carbon

Ions of gold monomer and clusters emitted from a liquid metal ion source we re mass-selected, and deposited on cleaved HOPG (highly oriented pyrolytic graphite) surfaces and on amorphous carbon thin films at room temperature w ith the impinging energy E-i from 0 to 500 eV. The coverage of deposited io ns were 1/100 and 1/1000 monolayers on HOPG surfaces and 1/3 monolayers on carbon films. Scanning tunneling microscopy of the HOPG surfaces deposited with low impinging energy (E-i<50 eV) revealed that large clusters with dia meters ranging from 2 to 5 nm and height of 1-2 layers were present instead of isolated monomers and original clusters. When E-i was higher than 100 e V, HOPG surfaces were damaged and only bumpy surfaces were observed by STM. Transmission electron microscopy of Au+-deposited carbon films showed the formation of clusters with diameter 0.5-20 nm, depending on the E-i and the time elapsed after deposition.