Ge adsorption on SiC(0 0 0 1): 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(0 0 0 1)- ( 3 × 3 ) R 30 ° and (3 × 3) surfaces. We find that Ge adatoms lying on the topmost sites of the ( 3 × 3 ) R 30 ° and (3 × 3) surfaces represent the energetically more stable configurations at the initial stage of the Ge adsorption on the SiC(0 0 0 1) 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 ( 3 × 3 ) R 30 ° surface, and Ge nanocluster on the (3 × 3) surface are the energetically more stable configurations, in accordance with recent experimental findings.