Growth of silicon nanostructures on graphite

Silicon nanostructures such as small clusters, superclusters, and elongated chains, with an average diameter of a few nanometers. have been synthesize d by magnetron sputtering on cleaved highly oriented pyrolytic graphite (HO PG). Scanning tunneling microscopy (STM) reveals that flat, defect-poor are as of the HOPG surface are covered with almost uniformly sized silicon clus ters of 0.6+/-0.2 nm, 5.1+/-1.2 nm, and 15.4+/-3 nm diameter. Surface regio ns with defects such as pits and craters, descending a few layers into the graphite surface, are sparsely covered with silicon. Most of the deposited material, with an average diameter of 2 nm, is found to be attached to the monatomic step edges forming the crater rims. A simulation of the growth pr ocess, i.e. deposition of silicon atoms onto a surface with built-in defect s, and subsequent surface diffusion and aggregation of the adatoms, convinc ingly reproduces most of the Si nanostructures observed in the STM topograp hs. (C) 2000 Elsevier Science B.V. All rights reserved.