Progress in characterizing submonolayer island growth: Capture-zone distributions, growth exponents, & hot precursors

Theodore L. Einstein, Alberto Pimpinelli, Diego Luis González, Josue R. Morales-Cifuentes

Research output: Contribution to journalConference article

6 Scopus citations

Abstract

In studies of epitaxial growth, analysis of the distribution of the areas of capture zones (i.e. proximity polygons or Voronoi tessellations with respect to island centers) is often the best way to extract the critical nucleus size i. For non-random nucleation the normalized areas s of these Voronoi cells are well described by the generalized Wigner distribution (GWD) Pβ(s) = asβ exp(-bs2), particularly in the central region 0.5 < s < 2 where data are least noisy. Extensive Monte Carlo simulations reveal inadequacies of our earlier mean field analysis, suggesting β = i + 2 for diffusion-limited aggregation (DLA). Since simulations generate orders of magnitude more data than experiments, they permit close examination of the tails of the distribution, which differ from the simple GWD form. One refinement is based on a fragmentation model. We also compare island-size distributions. We compare analysis by island-size distribution and by scaling of island density with flux. Modifications appear for attach-limited aggregation (ALA). We focus on the experimental system para-hexaphenyl on amorphous mica, comparing the results of the three analysis techniques and reconciling their results via a novel model of hot precursors based on rate equations, pointing out the existence of intermediate scaling regimes between DLA and ALA.

Original languageEnglish (US)
Article number012024
JournalJournal of Physics: Conference Series
Volume640
Issue number1
DOIs
StatePublished - Sep 28 2015
Event26th IUPAP Conference on Computational Physics, CCP 2014 - Boston, United States
Duration: Aug 11 2014Aug 14 2014

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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