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CENTER FOR SIMULATIONAL PHYSICS 
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Announcing a Simulational Physics Lunchtime Seminar: 

SPEAKER: Dr. Mihail N. Popescu
Emory University

TITLE: "Rate-equation Approach to Island Capture-zones and Size-distributions in Homoepitaxial Growth"

DATE: Tuesday, October 31, 2000

TIME: 12:30-1:30p

PLACE: Physics Building, Conference Room 201

Abstract: Growth of thin films or nano-scale structures by 
molecular beam epitaxy involves nucleation, aggregation
and coalescence of islands on two- or one-dimensional 
substrates. In the submonolayer regime, these
fundamental physical processes lead to a distribution of 
islands of various sizes. The total number of islands and the 
island-size distribution can be measured experimentally, 
and from their scaling behavior information about such 
quantities as activation energy for monomer diffusion, 
critical island size, and bond strength can be extracted.

A fully self-consistent rate-equation approach 
to the irreversible submonolayer growth in one and two 
dimensions is presented. This approach explicitly takes
into account both the existence of a denuded zone
around every island and the correlations between the size of
the island and the corresponding average capture zone.

For both one- and two-dimensional growth it is shown
that the average capture zone and the capture number of an 
island are dependent on the size of the island, and the
predicted size-dependency is in excellent agreement 
with experimental and Monte Carlo results. The rate 
equations predicted island-size distributions, as well
as average densities of monomers and islands, are in very 
good agreement with Monte Carlo simulation results over
the whole range of coverages in the pre-coalescence
regime.