Oxidation kinetics for Ni(111) and the structure of the oxide layers

Journal Article · Mon Jan 15 04:00:00 EST 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.75.033413· OSTI ID:20976653

Okazawa, T ^[1]; Nishizawa, T; Nishimura, T; Kido, Y ^[2]

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1. National Institute of Advanced Industrial Science and Technology, AIST Kansai, Midorigaoka, Ikeda, Osaka 563-8577 (Japan)
2. Department of Physics, Ritsumeikan University, Kusatsu, Shiga-ken 525-8577 (Japan)

The oxidation kinetics for Ni(111) surface and the structure of the oxide layers grown at room temperature were analyzed by high-resolution medium energy ion scattering using isotopically labeled {sup 18}O{sub 2}. Initially, the surface showed a reflection high energy electron diffraction (RHEED) pattern of the Ni(111)-(2x2)-O chemisorption structure at an oxygen exposure of a few langmuir (1 L:10{sup -6} Torr s) and started to form NiO(111) layers above 10 L. The oxide thickness was saturated with six atomic layers at oxygen exposure of 160 L. The saturated NiO(111) surface shows a (1x1) RHEED pattern not p(2x2) and consists of two domains: NiO(111)-[112]//Ni(111)-[112] (primary) and NiO(111)-[110]//Ni(111)-[112](a small fraction). The elemental depth profile corresponds to the octopolar reconstruction terminated with Ni (0.25 ML) [1 ML=1.33x10{sup 15} atoms/cm{sup 2}: areal density of NiO(111)]. The oxide surface grown epitaxially probably takes a precursor state of the octopolar structure with significant distortion because of a large lattice mismatch of 19% between NiO(111) and Ni(111). Tow step oxidation using {sup 18}O{sub 2} and {sup 16}O{sub 2} clearly indicates that oxidation takes place at the top surface obeying the Cabrera-Mott mechanism. The potential barrier for the jump from Ni into the NiO layer is derived to be 2.36 eV.

• OSTI ID: 20976653
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 3 Vol. 75; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMISORPTION
CRYSTAL DEFECTS
ELECTRON DIFFRACTION
EV RANGE 01-10
IONS
LAYERS
NICKEL
NICKEL OXIDES
OXIDATION
OXYGEN
REACTION KINETICS
REFLECTION
SURFACES
TEMPERATURE RANGE 0273-0400 K
THICKNESS