Publication Date

2018

Department

Chemistry; Mathematics; Physics and Astronomy; Materials Science and Engineering; Ames Laboratory

Campus Units

Chemistry, Mathematics, Materials Science and Engineering, Physics and Astronomy

OSTI ID+

1422772

Report Number

IS-J-9545

DOI

10.1021/acs.jpcc.7b12533

Journal Title

The Journal of Physical Chemistry C

Volume Number

122

Issue Number

8

First Page

4454

Last Page

4469

Abstract

We present an extensive experimental study of the conditions under which Cu forms encapsulated islands under the top surface layers of graphite, as a result of physical vapor deposition of Cu on argon-ion-bombarded graphite. When the substrate is held at 800 K during deposition, conditions are optimal for formation of encapsulated multilayer Cu islands. Deposition temperatures below 600 K favor adsorbed Cu clusters, while deposition temperatures above 800 K favor a different type of feature that is probably a single-layer intercalated Cu island. The multilayer Cu islands are characterized with respect to size and shape, thickness and continuity of the graphitic overlayer, relationship to graphite steps, and stability in air. The experimental techniques are scanning tunneling microscopy and X-ray photoelectron spectroscopy. We also present an extensive study using density functional theory to compare stabilities of a wide variety of configurations of Cu atoms, Cu clusters, and Cu layers on/under the graphite surface. The only configuration that is significantly more stable under the graphite surface than on top of it, is a single Cu atom. This analysis leads us to conclude that formation of encapsulated Cu islands is kinetically driven, rather than thermodynamically driven.

DOE Contract Number(s)

AC02-07CH11358; AC02-05CH11231

Language

en

Department of Energy Subject Categories

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Publisher

Iowa State University Digital Repository, Ames IA (United States)

Available for download on Wednesday, February 06, 2019

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