Journal article

Submonolayer nucleation and growth of copper on Ni(100)

Island densities and island sizes can be varied or even tailored by choice of external parameters in molecular beam epitaxy, i.e.: by the choice of substrate temperature. deposition rate, and coverage. We present a comprehensive study of the nucleation kinetics of Cu on Ni(100) using variable temperature scanning tunneling microscopy. The analysis of the saturation island density as a function of substrate temperature and deposition rate reveals that the smallest stable island abruptly changes from a dimer to a tetramer. The sizes of the critical nuclei are determined from the rate dependence of the saturation island density using mean-field nucleation theory consistent with results from the island size distribution using scaling theory. From the Arrhenius-plot, the microscopic quantities (migration barrier and dimer bond energy) have been deduced.

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