The surface structure of highly-relaxed IV-VI hetero-epitaxial layers was studied by using scanning tunnelling and scanning force microscopy. In bilayer structures which consisted of highly relaxed EuTe layers, covered by thick PbTe buffer layers, surface undulations with amplitudes as large as 5nm were observed. These undulations were completely decoupled from the epitaxial surface step structure and could be observed even for relatively large cap layer thicknesses. Deconvolution of the surface profiles showed that the surface undulations were caused purely by the non-uniform misfit dislocation network at the EuTe/PbTe interface. No indication was found that these dislocation strain fields gave rise to surface structures via preferential growth.

Observation of Large-Scale Surface Undulations due to Inhomogeneous Dislocation Strain Fields in Lattice-Mismatched Epitaxial Layers G.Springholz: Applied Physics Letters, 1999, 75[20], 3099-101