Ge adsorption on SiC(0001): An ab initio study

In this work we have performed an ab initio total energy investigation of the Ge adsorption process on the Si-terminated SiC(0001)-(root 3 x root 3)R30 degrees and (3 x 3) surfaces. We find that Ge adatoms lying on the topmost sites of the (root 3 x root 3)R30 degrees and (3 x 3) surfaces represent the energetically more stable configurations at the initial stage of the Ge adsorption on the SiC(0001) surface. The Si -> Ge substitutional adsorption processes have been examined as a function of the Si and Ge chemical potentials. Increasing the Ge coverage, we verify that the formation of Ge wetting layer on the (root 3 x root 3)R30 degrees surface, and Ge nanocluster on the (3 x 3) surface are the energetically more stable configurations, in accordance with recent experimental findings. (c) 2006 Elsevier B.V. All rights reserved.