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O: Oberflächenphysik

O 17: Hauptvortrag

O 17.1: Hauptvortrag

Dienstag, 23. März 1999, 15:15–16:00, S10

Epitaxial Growth of Metals with High Ehrlich-Scwoebel Barriers, and the Effect of Surfactants — •Juan J. de Miguel — Uni. Autonoma, E-28049 Madrid, Spanien

The so-called Ehrlich-Schwoebel (ES) barrier is the additional

energy that a diffusing adatom needs in order to cross an atomic

step and fall to a lower terrace. Its magnitude has a strong

influence on interlayer diffusion, and is therefore an important

parameter that determines the structural quality of epitaxial

films. Systems with large ES barriers develop kinetic

instabilities that affect their morphology and behavior: step

bunching during sublimation, de-bunching during growth, kinetic

roughning of the steps, etc. These phenomena will be reviewed

with the help of experimental data and computer simulations,

for both homo- and heteroepitaxial metallic films. On the

other hand the presence of a surfactant during growth can

reduce or even suppress the ES barrier: the atomistic

mechanisms responsible for this effect will also be discussed.