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Title: Copper Wetting of x-Al(2)O(3)(0001): Theory and Experiment

Abstract

XPS studies have been carried out on sputter deposited copper on a substantially hydroxylated {alpha}-Al{sub 2}O{sub 3}(0001) (sapphire) surface under ultra-high vacuum (UHV) conditions. XPS-derived Cu uptake curves show a sharp change in slope at a coverage of 0.35 monolayer (on a Cu/O atomic basis), indicative of initial layer-by-layer growth. CU(LMM) lineshape data indicate that, prior to the first break in the curve, Cu is oxidized to Cu(I). At higher coverages, metallic CU(0) is. observed. These data agree with first principles theoretical calculations, indicating that the presence of ad-hydroxyl groups greatly enhances the binding of Cu to bulk sapphire surfaces, stabilizing Cu(I) adatoms over two-dimensional metallic islands. In the absence of hydroxylation, calculations indicate significantly weaker Cu binding to the bulk sapphire substrate and non-wetting. Calculations also predict that at Cu coverages above 1/3 monolayer (ML), Cu-Cu interactions predominate, leading to Cu(0) formation. These results are in excellent agreement with experiment. The ability of surface hydroxyl groups to enhance binding to alumina substrates suggests a reason for contradictory experimental results reported in the literature for Cu wetting of alumina.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
9715
Report Number(s):
SAND99-2079J
TRN: AH200125%%24
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Surface Science
Additional Journal Information:
Other Information: Submitted to Surface Science; PBD: 10 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPPER; HYDROXYLATION; SAPPHIRE; SUBSTRATES; ALUMINIUM OXIDES; WETTABILITY; DEPOSITION; ADHESION

Citation Formats

Bogicevic, A., Jennison, D.R., Kelber, J.A., Niu, Chengyu, and Shepherd, K. Copper Wetting of x-Al(2)O(3)(0001): Theory and Experiment. United States: N. p., 1999. Web.
Bogicevic, A., Jennison, D.R., Kelber, J.A., Niu, Chengyu, & Shepherd, K. Copper Wetting of x-Al(2)O(3)(0001): Theory and Experiment. United States.
Bogicevic, A., Jennison, D.R., Kelber, J.A., Niu, Chengyu, and Shepherd, K. Tue . "Copper Wetting of x-Al(2)O(3)(0001): Theory and Experiment". United States. https://www.osti.gov/servlets/purl/9715.
@article{osti_9715,
title = {Copper Wetting of x-Al(2)O(3)(0001): Theory and Experiment},
author = {Bogicevic, A. and Jennison, D.R. and Kelber, J.A. and Niu, Chengyu and Shepherd, K.},
abstractNote = {XPS studies have been carried out on sputter deposited copper on a substantially hydroxylated {alpha}-Al{sub 2}O{sub 3}(0001) (sapphire) surface under ultra-high vacuum (UHV) conditions. XPS-derived Cu uptake curves show a sharp change in slope at a coverage of 0.35 monolayer (on a Cu/O atomic basis), indicative of initial layer-by-layer growth. CU(LMM) lineshape data indicate that, prior to the first break in the curve, Cu is oxidized to Cu(I). At higher coverages, metallic CU(0) is. observed. These data agree with first principles theoretical calculations, indicating that the presence of ad-hydroxyl groups greatly enhances the binding of Cu to bulk sapphire surfaces, stabilizing Cu(I) adatoms over two-dimensional metallic islands. In the absence of hydroxylation, calculations indicate significantly weaker Cu binding to the bulk sapphire substrate and non-wetting. Calculations also predict that at Cu coverages above 1/3 monolayer (ML), Cu-Cu interactions predominate, leading to Cu(0) formation. These results are in excellent agreement with experiment. The ability of surface hydroxyl groups to enhance binding to alumina substrates suggests a reason for contradictory experimental results reported in the literature for Cu wetting of alumina.},
doi = {},
journal = {Surface Science},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {8}
}