INFLUENCE OF DEPOSITION RATE AND TIME ON NUCLEATION OF ER ON A-C

摘要

Nucleation kinetics of UHV deposited erbium on amorphous carbon at room temperature and for atom arrival rates of 1.5 x 10(13)-1.8 x 10(14) atoms/cm(2) s is studied. For all deposition rates, the density of nuclei increased with time to a saturation value and remained stationary. It was found that the nucleation rate is linearly dependent on the deposition rate, indicating that a single-adatom constitutes a stable nucleus. At lower deposition rates (up to R = 1 x 10(14) atom/cm(2) s), the saturation density is constant and independent of R but at higher rates it increases with R according to the mathematical function n(s) = a + bexp(R/c). It is shown that the nucleation theory usually used to explain the experimental work needs some revision. For measured condensation coefficients, the diffusion length of adatoms x(s) = (1.53 +/- 0.01) nm, and the difference between adsorption and surface diffusion energies, E-a-E-sd = (0.12 +/- 0.01) eV are estimated. [References: 43]