First-principles pseudopotential total-energy calculations were applied to the effects of various surfactants upon Ge adsorption, diffusion and exchange on Si(111) surfaces. In the case of surfactant-covered surfaces such as Si(111):Ga-(1 x 1), Si(111):As-(1 x 1) and Si(111):Sb-(√3 x √3)R30º, Ge adatoms were usually incorporated into the surfactant layer. On Ga-covered surfaces, strong interactions were found between the Ge and Ga atoms. This resulted in large activation energies for both Ge surface diffusion and for exchange with an underlying Ga atom. In the case of As surfactants, the activation energies for adatom diffusion and exchange were much reduced because of the weak coupling between Ge and As atoms. On Sb-covered surfaced, exchange between adatoms and surfactants took place easily. However, surface diffusion was greatly suppressed due to a relatively large energy gain during the exchange process.

Ge Adatom Adsorption, Diffusion, and Exchange on Surfactant-Covered Si(111) Surfaces Y.J.Ko, K.J.Chang, J.Y.Yi: Physical Review B, 1999, 60[3], 1777-82