Published online by Cambridge University Press: 28 February 2011
Molecular beam epitaxy was used to grow Sim Gen superlattices on relaxed Si1-xGex buffer layers which symmetrize the strains between the heteroepitaxial layers. Samples with different superlattïce periodicities and individual layer thickness ratios were prepared. The compositions and defect structures of the GexSi1-x buffers have significant influence on the homogeneity and quality of the overlying superlattices. In particular, greater disorder was found in superlattice structures grown on Si0.5 Ge0.5 buffers than for those grown on buffer layers with significantly higher or lower Ge contents.