Si/Ge exchange mechanisms at the Ge(105) surface

Kinetic pathways for Si adatoms incorporation into Ge(105) are explored by density-functional theory. A very low activation energy (between ∼0.6 and ∼0.84 eV, depending on strain) for Si/Ge exchanges is found. Consequences on the Ge distribution within SiGe islands on Si(001) are discussed, illustrating why the above processes can influence strain relaxation. Fast exchange processes are shown to take place also in the presence of Si ad-dimers, further facilitating the creation of a Ge floating layer under Si deposition, lowering the surface energy of the exposed facet. © 2010 The American Physical Society.