Effects of surface topology on the formation of oxide islands on Cu surfaces

Zhou, Guangwen; Wang, Liang; Yang, Judith C.

doi:10.1063/1.1861147

Cited by 37 publications

(43 citation statements)

References 28 publications

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“…Using TEM observations, they found that the nucleation rate of oxide islands at 350 C on Cu(111) is much faster than that on the Cu(100) and Cu(110) surfaces. 7,70 To understand these results, we return to the original structures of the Cu(100), Cu(110), and Cu(111) surfaces. The Cu(100) surface has the most open structure and rapidly dissociates O 2 at hollow sites, as observed in experiments.…”

Section: Discussionmentioning

confidence: 99%

“…1 Previous experimental and theoretical studies have shown that the kinetics and morphology of Cu oxidation are complex and influenced by many factors, including surface orientation, ambient temperature, surface defects, and electric fields. [2][3][4][5][6][7][8][9] Most previous studies have focused on the formation of a monolayer (ML) of surface oxides. [10][11][12][13][14][15][16][17][18][19][20][21] However, the process of oxygen transport into the Cu sub-surface is a key step for the transformation between the oxygenated Cu surfaces and bulk oxides.…”

Section: Introductionmentioning

confidence: 99%

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Calculations of oxide formation on low-index Cu surfaces

Lian

Xiao

Yang

et al. 2016

The Journal of Chemical Physics

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Density-functional theory is used to evaluate the mechanism of copper surface oxidation. Reaction pathways of O2 dissociation on the surface and oxidation of the sub-surface are found on the Cu(100), Cu(110), and Cu(111) facets. At low oxygen coverage, all three surfaces dissociate O2 spontaneously. As oxygen accumulates on the surfaces, O2 dissociation becomes more difficult. A bottleneck to further oxidation occurs when the surfaces are saturated with oxygen. The barriers for O2 dissociation on the O-saturated Cu(100)-c(2×2)-0.5 monolayer (ML) and Cu(100) missing-row structures are 0.97 eV and 0.75 eV, respectively; significantly lower than those have been reported previously. Oxidation of Cu(110)-c(6×2), the most stable (110) surface oxide, has a barrier of 0.72 eV. As the reconstructions grow from step edges, clean Cu(110) surfaces can dissociatively adsorb oxygen until the surface Cu atoms are saturated. After slight rearrangements, these surface areas form a "1 ML" oxide structure which has not been reported in the literature. The barrier for further oxidation of this "1 ML" phase is only 0.31 eV. Finally the oxidized Cu(111) surface has a relatively low reaction energy barrier for O2 dissociation, even at high oxygen coverage, and allows for facile oxidation of the subsurface by fast O diffusion through the surface oxide. The kinetic mechanisms found provide a qualitative explanation of the observed oxidation of the low-index Cu surfaces.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculations of oxide formation on low-index Cu surfaces

Lian

Xiao

Yang

et al. 2016

The Journal of Chemical Physics

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“…While some metals and semimetals can grow oxide layers homogeneously without the aid of impurities or surface defects (such as Ru (0001) 254,255 showed that this is not the case on Cu(100) and Cu(110) films. It is indeed possible, considering the different nature of oxide formation on the three low-index surfaces, that different defects play a more or less important role in different oxide nucleation conditions.…”

Section: Nucleation Sitesmentioning

confidence: 99%

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Gattinoni

Michaelides

2015

Surface Science Reports

280

258

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The oxidation and corrosion of metals are fundamental problems in materials science and technology that have been studied using a large variety of experimental and computational techniques. Here we review some of the recent studies that have led to significant advances in our atomic-level understanding of copper oxide, one of the most studied and better understood metal oxides. We show that a good atomistic understanding of the physical characteristics of cuprous (Cu 2 O) and cupric (CuO) oxide and of some key processes of their formation has been obtained. Indeed, the growth of the oxide has been proven to be epitaxial with the surface and to proceed, in most cases, through the formation of oxide nano-islands which, with continuous oxygen exposure, grow and eventually coalesce. We also show how electronic structure calculations have become increasingly useful in helping to characterise the structures and energetics of various Cu oxide surfaces. However a number of challenges remain. For example, it is not clear under which conditions the oxidation of copper in air at room temperature (known as native oxidation) leads to the formation of a cuprous oxide film only, or also of a cupric overlayer. Moreover, the atomistic details of the nucleation of the oxide islands are still unknown. We close our review with a perspective on future work and discuss how recent advances in experimental techniques, bringing greater temporal and spatial resolution, along with improvements in the accuracy, realism and timescales achievable with computational approaches make it possible for these questions to be answered in the near future.

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“…The oxidation of copper has been studied extensively on single crystals [42][43][44] and alloy systems [45] . Surface oxide films have been found to form in parallel with extensive dissolution and sub-surface oxidation processes.…”

Section: Redox Chemistry Of Cu: Oxidation Of Cu 2 O To Cuomentioning

confidence: 99%