The oxidation of vacuum deposited films of copper

Hapase, M.G.; Gharpurey, M. K.; Biswas, Anupam

doi:10.1016/0039-6028(68)90165-9

Cited by 38 publications

(9 citation statements)

References 15 publications

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“…The lowest unoccupied orbital (LUMO) of these Cu 2+ species is, however, below the valence band maximum of ZnO, suggesting electron transfer and reduction of the Cu-ions to Cu + in n-type ZnO. It is also worth pointing out that replacement of 1 [62], thin film [63][64][65], and nanoscopic powder form [66].Further characterization of the (Ö3 · Ö3)R30°structure is required to finalize and refine the model. Nevertheless, it is likely that this structure involves Cu + sites and it will be important to probe the influence of such sites on the catalytic activity of the Cu/ZnO system.…”

Section: Discussionmentioning

confidence: 96%

Growth of Copper on Single Crystalline ZnO: Surface Study of a Model Catalyst

2005

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Copper, vapor-deposited on the polar, Zn-terminated ZnO(0001) surface is investigated in view of its suitability as model system for the technologically important Cu/ZnO catalyst. The structure and electronic properties of Cu clusters on ZnO(0001)-Zn have been studied with scanning tunneling microscopy (STM), low energy electron diffraction (LEED), ultraviolet photoelectron spectroscopy (UPS), and low-energy He + ion scattering (LEIS). At room temperature copper grows as two-dimensional (2D) clusters only at very low coverages of 0.001-0.05 equivalent monolayers (ML). At coverages greater than 0.01 ML, 3D clusters start to develop. This is contrasted to Cu growth on the oxygen-terminated ZnO(0001bar) surface, where a strong adhesion between Cu and the ZnO substrate results in an initial wetting of the surface by Cu. On ZnO(0001)-Zn, surface roughness and sputter damage change the growth mode to more 2D-like. Annealing in UHV results in well-separated, hexagonal clusters rotationally aligned with the substrate. Annealing of 2-5 ML Cu deposits on the ZnO(0001)-Zn surface in 10 )6 mbar O 2 results in the formation of a (Ö3 · Ö3)R30°superstructure with respect to the ZnO lattice. This superstructure likely contains Cu + sites. The suitability of the different surface morphologies to probe specific sites that are thought to be active for catalytic processes is discussed.

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Section: Discussionmentioning

confidence: 96%

Growth of Copper on Single Crystalline ZnO: Surface Study of a Model Catalyst

2005

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“…Given that CuO x phase nucleates under strain and will slowly transform into CuO after the stress released, the local lattice distortion may exist which allows for ~5% error in correlating the experimental and calculated results. It is worth mention that Cu 3 O 2 phase has been frequently reported during the oxidation of Cu and Cu 2 O 34,35 . Unfortunately, since Cu 3 O 2 is unstable and can be easily oxidized to CuO, its structural details remain mysterious due to the lack of atomic-scale structural investigation.…”

Section: Resultsmentioning

confidence: 95%

Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

Chen

et al. 2021

Nat Commun

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From the mechanical perspectives, the influence of point defects is generally considered at high temperature, especially when the creep deformation dominates. Here, we show the stress-induced reversible oxygen vacancy migration in CuO nanowires at room temperature, causing the unanticipated anelastic deformation. The anelastic strain is associated with the nucleation of oxygen-deficient CuOx phase, which gradually transforms back to CuO after stress releasing, leading to the gradual recovery of the nanowire shape. Detailed analysis reveals an oxygen deficient metastable CuOx phase that has been overlooked in the literatures. Both theoretical and experimental investigations faithfully predict the oxygen vacancy diffusion pathways in CuO. Our finding facilitates a better understanding of the complicated mechanical behaviors in materials, which could also be relevant across multiple scientific disciplines, such as high-temperature superconductivity and solid-state chemistry in Cu-O compounds, etc.

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“…direct proportion to copper volume percentage in the matrix. 12,25 So this linear relation should correspond to oxidation kinetics of copper particle. We have further studied the size-dependent oxidation kinetics of copper particles in air, which will be reported later.…”

Section: Resultsmentioning

confidence: 97%

Optical Absorption of Copper Nanoparticles Dispersed within Pores of Monolithic Mesoporous Silica

Liu

Cai

2002

J. Mater. Res.

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Nano-sized copper particles are loaded into the pores of monolithic mesoporous silica by soaking and drying, followed by thermal reduction of copper nitrate [Cu(NO 3 ) 2 ] in a hydrogen atmosphere at 973 K for 90 min. It has been shown that copper nanoparticles are isolated from each other and highly uniformly dispersed inside the pores of silica. It is found that the surface plasmon resonance peak of the copper particles shows a significant red-shift with decreasing the particle size, which is in contrast to the corresponding fully embedded system. The peak decreases with exposure time to air and exhibits a linear relation with logarithmic exposure time. This red-shift phenomenon and decrease are explained on the basis of the structural features of this new composite or coexistence of local porosity and the nanoparticle's free surface in contact with air.

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The oxidation of vacuum deposited films of copper

Cited by 38 publications

References 15 publications

Growth of Copper on Single Crystalline ZnO: Surface Study of a Model Catalyst

Growth of Copper on Single Crystalline ZnO: Surface Study of a Model Catalyst

Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

Optical Absorption of Copper Nanoparticles Dispersed within Pores of Monolithic Mesoporous Silica

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