Simulation of Lead Nanoislands Growth using Density Functional Theory

S.I. Bozhko (1) , A.S. Ksenz (2, 1) , A.M. Ionov (1) , D. Fokin (3, 1) , V. Dubost (3) , F. Debontridder (3) , T. Cren (3) , D. Roditchev (3)

1 ISSP - Osipyan Institute of Solid State Physics
2 MSU - Lomonosov Moscow State University
3 INSP-E2 - Spectroscopie des nouveaux états quantiques

Many metals adopt a face-centered cubic structure in their bulk form, but they often exhibit important structural and morphological deviations when confined to nanoscale or interacting with the environment. In this paper, the growth of lead nanoislands on silicon(111) has been investigated in ultrahigh vacuum for different evaporation conditions: temperature, flux, annealing time, and source or surface condition. Unexpected Pb icosahedral nanoparticles of a very large, up to 100 nm, size have been revealed to grow on Si(111) substrate. The coexistence between these 5-fold twinned Pb pyramids and expected face-centered cubic (fcc) Pb single crystals has been investigated in situ by Scanning Tunneling Microscopy (STM) and ex situ by Scanning Electron Microscopy (SEM). We found that the growth of the Pb icosahedral particles only occurs when very high Pb diffusion conditions are met, with a high quality of the silicon surface and a purified lead source. The icosahedral pyramids have been observed to be more stable upon ripening at room temperature than fcc single crystals.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S.I. Bozhko, A.S. Ksenz, A.M. Ionov, D. Fokin, V. Dubost, et al.. Simulation of Lead Nanoislands Growth using Density Functional Theory. Physics Procedia, 2015, 71, pp.332 - 336. ⟨10.1016/j.phpro.2015.08.345⟩. ⟨hal-01387506⟩