Fourier transform infrared-attenuated total reflectance spectroscopy, together with H adsorption, were used to study surface-layer compositions. This revealed a reversible place exchange between Ge and Si on Ge-covered (001) surfaces when the latter were dosed with atomic H at high temperatures. First-principles calculations confirmed the existence of a thermodynamic driving force for this place exchange. A dimer vacancy diffusion-assisted mechanism which was limited by vacancy interactions was proposed in order to explain the interesting kinetics of the place exchange; which exhibited no time-dependence.

Hydrogen-induced Si surface segregation on Ge-covered Si(001) E.Rudkevich, F.Liu, D.E.Savage, T.F.Kuech, L.McCaughan, M.G.Lagally: Physical Review Letters, 1998, 81[16], 3467-70