Direct observation of the nucleation and growth modes of Ag/Si(111)

摘要: Abstract Direct observation in an ultrahigh vacuum scanning electron microscope (SEM) has revealed the growth modes of Ag on Si(111), previously deduced indirectly from analysis Auger spectra, and form number crystallites as a function deposition time temperature. At high temperatures, T s > 200°C, silver grows definitively Stranski-Krastanov (layer plus island) mode, with very strong dependence island density temperature, varying ≲ l0 6 to ∼ 10 cm −2 between = 500 200°C. The crystals have more or less regular hexagonal forms (111) {1 1 1} faces predominating height width ratio which decreases range 0.1–0.6. temperatures below is too be observed directly by SEM, appears grow Frank-van der Merwe layer) mode. However, this uniform deposit unstable heating above annealed deposits recreate rather similar islands. An published amplitude-time curves made estimate initial produced depositions 200° C, it shown that these densities constitute reasonable extrapolation higher temperature SEM values. A model given outline applied Ag/Si(111). It argued determined largely instability at even though condensation complete. low becomes essentially equivalent for enough density, kinetic than thermodynamic reasons, without any change basic mechanism.