Masters Theses

Abstract

"This thesis presents an investigation on epitaxial electrodeposition of metal oxides on Au single crystals. Electrodeposition offers an excellent control of the driving force and deposition rate through precise control of the applied cuITent or potential. The amount of charge passed to the working electrode provides a measure of the deposition rate and the shape of the current-time transients indicates the dimensionality of the growth.

Epitaxial films help in exploiting the intrinsic properties of the material in a device rather than its grain boundaries. The most active crystallographic orientation for a desired property can be selected by careful selection of the substrate. Electrodeposited films have a tendency to develop a preferred orientation even on polycrystalline substrate depending on the rate of deposition and the solution pH. In this work, Cu2O is deposited on Au single crystal that has a different crystallographic orientation than the preferred orientation that is determined by the kinetics of the process. At low deposition rates the film follows the orientation of the substrate indefinitely. At higher deposition rates, the film follows the orientation of the substrate, the thermodynamically-controlled orientation, until it reaches a critical thickness, after which it switches to the kineticallyprefe1Ted orientation. Ordered nanostructures are produced on the surface at thicknesses exceeding this critical thickness.

Superlattices are a type of crystalline material abruptly modulated with respect to composition or structure or both. Multilayers and superlattices are both modulated materials but superlattices have the additional constraint of being crystallographically coherent. Superlattices of Pb-Tl-O were epitaxially electrodeposited at room temperature on single crystal Au(I00) by periodically pulsing the current anodically between 0.05 and 5 mA/cm2 from an aqueous solution of 0.005 M TINO3 and 0.1 M Pb(NO3)2 in 5M NaOH. An epitaxial relationship is obtained through formation of a coincidence lattice in which the Pb-Tl-O film is rotated 45° in-plane with respect to the gold substrate"-- Abstract, p. iv

Advisor(s)

Switzer, Jay A.

Committee Member(s)

Ludlow, Douglas K.
Patterson, Gary P.

Department(s)

Chemical and Biochemical Engineering

Degree Name

M.S. in Chemical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 2002

Pagination

x, 58 pages

Note about bibliography

Includes bibliographical references page 57

Rights

© 2002 Kiten Mahendra Kothari, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

ElectroplatingSuperlattices as materials

Thesis Number

T 8171

Print OCLC #

52731042

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