IMAGING OF MISFIT DISLOCATION FORMATION IN STRAINED-LAYER HETEROEPITAXY BY ULTRAHIGH-VACUUM SCANNING-TUNNELING-MICROSCOPY

We present a novel technique for the study of strain relaxation in lattice-mismatched heteroepitaxy based on scanning tunneling microscopy. Because of the low limit for detection of single misfit dislocation glide lines, the early stages of strain relaxation can be studied quantitatively with high precision. Using this method for the study of molecular beam epitaxy of EuTe on PbTe(111), the existence of an initial sluggish strain relaxation process, undetectable by in situ reflection high-energy electron diffraction, is observed in an actual growth experiment.