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Title of article :
Growth of Au clusters on amorphous Al2O3: are small clusters more mobile than atoms?
Author/Authors :
Carrey، نويسنده , , J and Maurice، نويسنده , , J.-L and Petroff، نويسنده , , F and Vaurès، نويسنده , , A، نويسنده ,
Issue Information :
هفته نامه با شماره پیاپی سال 2002
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Abstract :
We study the growth by sputtering of Au clusters on amorphous Al2O3 using transmission electron microscopy (TEM). The weak decrease of the cluster density with temperature is a clear sign that the defects of the substrate strongly influence the growth. We observe two phenomena which cannot be explained in a classical model of nucleation on defects: (i) there is some missing material in TEM micrographs that can re-appear after annealing at room temperature, and (ii) there is a delay in the nucleation of clusters. Moreover, in the case of clusters visible by TEM, we show by comparing the observed growth with kinetic Monte-Carlo simulations that clusters detach from defects above a critical size. We propose that a similar behavior explains the blockade and re-appearance of the invisible material, and the delay in nucleation: a large density of clusters nucleate on traps that release them at a size below TEM resolution (≃1 nm in these experiments).
Keywords :
GROWTH , Surface defects , Clusters , Electron microscopy , Monte Carlo simulations , Aluminum oxide , Amorphous surfaces , Gold
Journal title :
Surface Science
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Link To Document :