It was recalled that several experimental and theoretical studies of diffusion kinetics at the nanoscale had shown that the time evolution (x proportional to tck) differed from the classical Fickian law (kc = 0.5). However, all of the work was based upon crystalline samples or models. Here, the diffusion kinetics of a thin amorphous Si layer into amorphous Ge was reported to account for the rising              importance of amorphous materials. Employing surface sensitive techniques, the initial kc was found to be 0.7. After some monolayers of Si dissolved into the Ge, kc changed into the generally expected classical Fickian law, with kc = 0.5.

Transition from Anomalous Kinetics towards Fickian Diffusion for Si Dissolution into Amorphous Ge. Z.Balogh, Z.Erdélyi, D.L.Beke, G.A.Langer, A.Csik, H.G.Boyen, U.Wiedwald, P.Ziemann, A.Portavoce, C.Girardeaux: Applied Physics Letters, 2008, 92[14], 143104