Surface topography after single particle and cluster impacts on gold surfaces

Abstract

The surface topography arising from energetic Au particle impacts on Au is investigated. Both individual particle and cluster impacts are considered. For individual Au atoms, 20 successive impacts at 5 keV are considered on a low index face (0 1 0) and a higher index face (3 11 0) with a similar orientation. In both cases, all ejected particles occur in the first 10 ps after impact. It is shown that on the (0 1 0) surface, fairly steep sided flat-bottomed holes surrounded by flat topped adatom structures are formed whereas, on the (3 11 0) surface, facetted structures begin to form. For the cluster impact which deposits the same amount of energy in the surface as the 20 single particle impacts, the ejection yield is much higher as atoms boil off from the surface for times as long as 50 ps after impact. The resulting topography formed on the surface is independent of the cluster shape but is characteristic of the structure of the original crystal surface and substrate.

Keywords:

• sputtering
• ion bombardment
• cluster impact
• crystal orientation

Acknowledgement

RS would like to thank Ph.D student Marc Robinson for writing the visualization code which produced the images for this paper.