Surface dynamics of III-V semiconductors studied by in situ X-ray diffraction during molecular beam epitaxy

摘要

We study the coarsening of two-dimensional crystalline islands on the (001) face of GaAs, InAs and GaSb after deposition at typical growth conditions in molecular beam epitaxy. The time-resolved island/pit size distributions are measured in situ using synchrotron X-ray diffraction and are analyzed together with the diffraction intensity oscillations during deposition. Whereas the deposition kinetics is similar for the three materials, they strongly differ in the coarsening. During coarsening, the mean correlation length grows proportional to t(n). GaAs shows coarsening exponents around n = 1 and an exponential island size distribution, in clear contrast to the behavior of InAs and GaSb, where we find coarsening closer to the expected Ostwald ripening behavior (n between 1/3 and 1/2) on InAs and extremely slow kinetics on GaSb.