Initial stages of Ni-driven nanostructures growth on Ag/Ge(111)-√3×√3 surface

Using STM, we have investigated early stages of nanostructures formation upon room temperature (RT) deposition of 0.12 ML Ni onto Ag/Ge(111)-√3×√3 surface. While RT growth mode is determined by cluster formation, annealing up to 200°C promotes cluster nucleation. Further annealing results in creation of hexagonal-shaped islands which conserve on the surface in the unchanged form even after 800°C annealing. Unusual thermal stability of these islands is explained in terms of Ni-Ge compounds formation.