Flat-surface, step-edge, facet-facet, and facet-step diffusion barriers in growth of a Pb mesa
SCIE
SCOPUS
- Title
- Flat-surface, step-edge, facet-facet, and facet-step diffusion barriers in growth of a Pb mesa
- Authors
- Han, Y; Lu, GH; Lee, BJ; Liu, F
- Date Issued
- 2008-07-01
- Publisher
- ELSEVIER SCIENCE BV
- Abstract
- We obtain important energy parameters for understanding growth kinetics of a faceted Pb mesa. Specifically, extensive calculations of diffusion barriers are performed for a Pb adatom: (i) on a flat Pb(111) or Pb(001) surface; (ii) crossing a single A- or B-step edge on Pb(111) surface; (iii) crossing a facet-facet edge between Pb(111) facet and Pb(001) facet, or between Pb(111) facet and Pb(11 (1) over bar) facet; (iv) crossing a facet-step joint between Pb(001) facet and A-step, or between Pb(11 (1) over bar) facet and B-step, using a modified embedded atom method. We investigate two different diffusion modes: direct hopping of an adatom, and exchange mechanism between an adatom and substrate atom(s). Direct hopping diffusion is more favorable over exchange mechanism for an adatom on a flat (111) or (001) surface. Diffusion crossing A-step edge favors direct hopping, while diffusion crossing B-step edge favors exchange mechanism. For facet-facet or facet-step diffusion, the exchange mechanism is always favorable over direct hopping. The diffusion barriers obtained here have been used to reasonably explain the intriguing kinetic growth of a Pb mesa in recent experiments. In addition, we also discuss low-index planes of Pb((1) over bar 10) crystallographic zone related to the choices of sidewalls in the formation of a Pb mesa by calculating corresponding surface free energies. (c) 2008 Elsevier B.V. All rights reserved.
- Keywords
- Pb mesa growth; surface diffusion barrier; surface free energy; modified embedded atom method; EMBEDDED-ATOM-METHOD; SELF-DIFFUSION; SADDLE-POINTS; RELAXATIONS; TEMPERATURE; IMPURITIES; POTENTIALS; PB/SI(111); MECHANISM; KINETICS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/108084
- DOI
- 10.1016/j.susc.2008.05.009
- ISSN
- 0039-6028
- Article Type
- Article
- Citation
- SURFACE SCIENCE, vol. 602, no. 13, page. 2284 - 2294, 2008-07-01
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