Nucleation and Growth of Order in Cu(3)Au (111) Films

Bonham, Scott William

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Description

Title

Nucleation and Growth of Order in Cu(3)Au (111) Films

Author(s)

Bonham, Scott William

Issue Date

1997

Doctoral Committee Chair(s)

C. Peter Flynn

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Engineering, Materials Science

Language

eng

Abstract

During epitaxial growth of (111) face-centered cubic crystal films, such as disordered $\rm Cu\sb3Au,$ there are two possible ways that successive layers can be laid down, leading to two types of stacking domains. However, a small vicinal miscut $(0.5\sp\circ {-}1\sp\circ )$ of the crystal surface introduces step edges that change nucleation preferences of the domains, resulting in one being preferred over the other by ratios up to 700:1. Fifteen samples were measured and this preference has been found to depend systematically and strongly on the magnitude and direction of the sample miscut. A qualitative RHEED study confirms that a preference for one of the stacking senses is present after deposition of a few monlolayers of $\rm Cu\sb3Au.$ The observed behavior of the film can be explained by a model in which Cu and Au atoms minimize their number of Nb nearest neighbors when growing over the Nb step edges. This represents both a discovery of a new phenomena in epitaxial nucleation and a technique for the production of improved epitaxial films.

Graduation Semester

1997

Type of Resource

text

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