AES study of sulfur surface segregation on polycrystalline copper
作者:
B. Singh,
R. W. Vook,
E.‐A. Knabbe,
期刊:
Journal of Vacuum Science and Technology
(AIP Available online 1980)
卷期:
Volume 17,
issue 1
页码: 29-33
ISSN:0022-5355
年代: 1980
DOI:10.1116/1.570418
出版商: American Vacuum Society
关键词: COPPER;POLYCRYSTALS;ULTRAHIGH VACUUM;SULFUR;SURFACE PROPERTIES;CHEMICAL COMPOSITION;TIME DEPENDENCE;DEGASSING;TEMPERTURE DEPENDENCE;SEGREGATION;DIFFUSION;AUGER ELECTRON SPECTROSCOPY
数据来源: AIP
摘要:
The surfaces of four polycrystalline copper samples were examined under UHV conditions by AES: OFHC Cu, 99.99% Cu, 99.9999% Cu, and 0.086 wt. % Ag in OFHC Cu. Surface chemical compositions in the range of 25°–600°C were determined. Sulfur concentrations on the surfaces at various temperatures were also measured as a function of time. In almost all cases the sulfur concentration increased as (time)1/2. This process was interpreted in terms of a model based on diffusion controlled ’’outgassing’’ in which the sulfur segregated to the surface instead of vaporizing. The activation energies for this process for the four samples ranged from 0.18 to 0.31 eV/atom. RHEED data from an OFHC Cu sample indicated that sulfur formed an orthorhombic Cu2S structure on the surface. Around 500°C the Ag–Cu alloy experienced a complex, rapid stage of segregation of sulfur. Above this temperture range the surface sulfur concentration dropped rapidly, reaching zero at 600°C.
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