Mesoscopic pattern formation during initial oxidation of Ni(111) observed by electron emission microscopy

Kamada, Toshihiko; Sogo, M.; Aoki, Masaru; Masuda, S.

doi:10.1016/j.susc.2007.12.003

Cited by 7 publications

(3 citation statements)

References 40 publications

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“…At the surface of a sample placed in our analysis chamber the intensity of the beam is approximately 6 × 10 12 atoms s −1 cm −2 . This is a conservative estimate assuming 100% Faraday cup detection efficiency and considering a beam with a diameter equal to the measured FWHM; however, it represents an order-ofmagnitude increase over the intensity of conventional MDS set-ups [17]. The brightness of the focused beam is 3.5 × 10 16 atoms s −1 sr −1 cm −2 , comparable to other laser-focused metastable-atom beamlines [14,18].…”

Section: Resultsmentioning

confidence: 77%

Scanning magneto-optical lens for surface analysis

Pratt¹,

Jacka²

2009

J. Phys. D: Appl. Phys.

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We demonstrate the essential principles for performing a novel form of metastable-atom microscopy, namely focusing and scanning of a He 23S beam. A magneto-optical lens, in conjunction with time-varying magnetic field components, has been used to scan a beam of He 23S atoms across a sample surface in a manner analogous to other scanning probe techniques. The instrument developed is the first to apply methods in the laser manipulation of atoms specifically to the study of surfaces. With the lens in its current arrangement, a beam of He 23S atoms with an intensity of ∼6 × 1012 atoms s−1 cm−2 may be directed anywhere within a sample area of ∼64 mm2 at a focal distance of 1.4 m and with a focal spot full-width at half-maximum of <2 mm. Such control over the intensity and position of the He 23S beam greatly benefits the surface analysis technique of metastable de-excitation spectroscopy, as demonstrated with example spectra from a clean Si(1 1 1) 7 × 7 surface.

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Section: Resultsmentioning

confidence: 77%

Scanning magneto-optical lens for surface analysis

Pratt¹,

Jacka²

2009

J. Phys. D: Appl. Phys.

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“…Theoretical approaches to elucidate the mechanisms for the oxidation of metal NPs have involved the development of spherical models [8][9][10] based on the established kinetic mechanism for bulk metal surface oxidation by Cabrera and Mott [6]. These theories assume metal surfaces covered by an oxide film with consistent thickness, whereas the early oxidation stage (not yet completely covered by oxide film) starts from the nucleation and growth of oxide islands [11][12][13]. Nucleation of oxide islands occurs when dissociatively adsorbed oxygen becomes supersaturated on the metal surface, and oxide islands grow laterally, link together, and then form a continuous oxide film [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…These theories assume metal surfaces covered by an oxide film with consistent thickness, whereas the early oxidation stage (not yet completely covered by oxide film) starts from the nucleation and growth of oxide islands [11][12][13]. Nucleation of oxide islands occurs when dissociatively adsorbed oxygen becomes supersaturated on the metal surface, and oxide islands grow laterally, link together, and then form a continuous oxide film [12][13][14][15][16]. However, various crystal facets coexist on the surfaces of NPs, and atoms are present at special sites such as edges or corners in high density.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic growth of NiO nanorods from Ni nanoparticles by rapid thermal oxidation

Koga

Hirasawa

2013

Nanotechnology

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NiO nanorods with extremely high crystallinity were grown by rapid thermal oxidation through exposure of Ni nanoparticles (NPs) heated above 400° C to oxygen. Oxidation proceeds by nucleation of a NiO island on a Ni NP that grows anisotropically to produce a NiO nanorod. This process differs completely from that under mild oxidation conditions, where the surface of the NPs is completely covered with an oxide film during the early stage of oxidation. The observed novel behaviour strongly suggests an interfacial oxidation mechanism driven by the dissolution of adsorbed oxygen into the Ni NP sub-surface region, subsequent diffusion and reaction at the NiO/Ni interface. The early oxidation conditions of metal NPs impose a significant influence on the entire oxidation process at the nanoscale and are therefore inherently important for the precise morphological control of oxidized NPs to design functional nanomaterials.

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Instrumentation

Bauer¹

2014

Surface Microscopy With Low Energy Electrons

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Mesoscopic pattern formation during initial oxidation of Ni(111) observed by electron emission microscopy

Cited by 7 publications

References 40 publications

Scanning magneto-optical lens for surface analysis

Scanning magneto-optical lens for surface analysis

Anisotropic growth of NiO nanorods from Ni nanoparticles by rapid thermal oxidation

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