Authors

M. I. Nandasiri; P. Nachimuthu; T. Varga; V. Shutthanandan; W. Jiang; Svnt Kuchibhatla; S. Thevuthasan; S. Seal;A. Kayani

Comments

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Abbreviated Journal Title

J. Appl. Phys.

Keywords

MOLECULAR-BEAM EPITAXY; DEPOSITION RATE; ELECTRONIC-STRUCTURE; SURFACE-STRUCTURE; PLANE SAPPHIRE; CERIA SURFACES; TEMPERATURE; SPECTROSCOPY; STABILITY; CEO2(001); Physics, Applied

Abstract

Growth rate-induced epitaxial orientations and crystalline quality of CeO2 thin films grown on Al2O3(0001) by oxygen plasma-assisted molecular beam epitaxy were studied using in situ and ex situ characterization techniques. CeO2 grows as three-dimensional (3D) islands and two-dimensional layers at growth rates of 1-7 angstrom/min and > = 9 angstrom/min, respectively. The formation of epitaxial CeO2(100) and CeO2(111) thin films occurs at growth rates of 1 angstrom/min and > = 9 angstrom/min, respectively. Glancing-incidence x-ray diffraction measurements have shown that the films grown at intermediate growth rates (2-7 angstrom/min) consist of polycrystalline CeO2 along with CeO2(100). The thin film grown at 1 angstrom/min exhibits six in-plane domains, characteristic of well-aligned CeO2(100) crystallites. The content of the poorly aligned CeO2(100) crystallites increases with increasing growth rate from 2 to 7 angstrom/min, and three out of six in-plane domains gradually decrease and eventually disappear, as confirmed by XRD pole figures. At growth rates > = 9 angstrom/min, CeO2(111) film with single in-plane domain was identified. The formation of CeO2(100) 3D islands at growth rates of 1-7 angstrom/min is a kinetically driven process unlike at growth rates > = 9 angstrom/min which result in an energetically and thermodynamically more stable CeO2(111) surface.

Journal Title

Journal of Applied Physics

Volume

109

Issue/Number

1

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

7

WOS Identifier

WOS:000286219300050

ISSN

0021-8979

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