Influence of strain on diffusion at Ge(111) surfaces

The measurement of the density of two-dimensional islands by scanning tunneling microscopy after submonolayer growth is used to determine the strain dependence of surface diffusion. Templates of strained and relaxed Ge surfaces with the same surface reconstruction are prepared for comparison. The diffusion barrier for Ge and Si adatoms is found to increase with increasing compressive strain of the Ge(111) substrate. When the strain increases from relaxed Ge to Ge strained to the Si lattice constant, the diffusion barrier is estimated to increase by similar to60 meV. (C) 2002 American Institute of Physics