Anomalous surface diffusion of C 60 and anisotropic growth of nano islands on Ni(111)
Journal
Journal of Nanoscience and Nanotechnology
Journal Volume
8
Journal Issue
2
Pages
602-607
Date Issued
2008
Author(s)
Abstract
The migration behavior of C 60 on Ni(111) has been inferred from its growth morphology at various substrate temperatures, as observed with scanning tunneling microscopy. The number density of islands increased and their average sizes decreased anomalously in the temperature range of ∼573 K to ∼973 K. This trend contradicts the prediction in conventional nucleation theory. At low and high temperatures, C 60 commence nucleation on both sides of surface steps in a "bi-directional step flow" mode. However, anisotropy occurs within an intermediate temperature range, in which C 60 nucleate predominantly at upper step edges. Surprisingly, in-situ growth measurements at this intermediate temperature range revealed that C 60 actually start nucleating from lower step edges, with concomitant formation of Ni terraces underneath. These anomalous thermal dependence of diffusivity and the peculiar growth morphology of C 60 on Ni(111) are attributed to C 60-induced reconstruction of Ni(111) at higher temperature. Copyright © 2008 American Scientific Publishers All rights reserved.
SDGs
Type
conference paper