Step and kink correlations on vicinal Ge(100) surfaces investigated by electron diffraction

Abstract

Using spot profile analysis in low-energy electron diffraction, we have investigated vicinal Ge(100) surfaces, which were miscut by 2.7° and 5.4°, respectively, in [011] direction with respect to the surface normal. Within the kinematic approximation the morphology was evaluated quantitatively both perpendicular and parallel to the step edge direction. In contrast to vicinal Si(100) surfaces with similar miscut angles, the Ge(100) surfaces still show an alternating configuration of (2×1) and (1×2) reconstructed (100) terraces, which are separated by steps of single atomic height. From the spot profiles and their energy dependence we extracted the morphological parameters such as the average terrace width, the variance of the terrace size distribution, and the average kink separation. Furthermore, step energies on the vicinal Ge(100) surfaces were estimated. These turn out to be significantly lower than for Si(100) and lead to the formation of the observed double domain structure.