The measurement of the two-dimensional island density after sub-monolayer deposition was used to determine the effect of material, surface reconstruction, and strain on surface diffusion. Specifically prepared strained and relaxed Ge surfaces were used as templates. Scanning tunnelling microscopy was used to determine the density of two-dimensional islands. The change of the material (from Si to Ge) increases the diffusion length substantially. The diffusion length was increased by a factor of 10 when the substrate material was changed from Si to Ge. The effect was weaker when the deposited material was changed. The diffusion barrier for Ge and Si adatoms was found to increase with increasing compressive strain of the Ge(111) substrate. Unexpectedly, the change of the surface reconstruction from (7 x 7) to (5 x 5) had negligible influence on the diffusion length.

Influence of Material, Surface Reconstruction and Strain on Diffusion at the Ge(111) Surface. V.Cherepanov, B.Voigtländer: Physical Review B, 2004, 69[12], 125331 (8pp)