Ge/Ag(111): SURFACE ALLOY OF A SEMICONDUCTOR ON A METAL

1999 ◽  
Vol 06 (05) ◽  
pp. 929-934 ◽  
Author(s):  
H. OUGHADDOU ◽  
B. AUFRAY ◽  
J. M. GAY
Keyword(s):  
Phase Separation ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Room Temperature ◽  
Surface Segregation ◽  
Experimental Studies ◽  
Surface Alloy ◽  
Layer By Layer ◽  
Kinetics Of ◽  
Monolayer Coverage

We present one of the first experimental studies of the formation of an ordered surface alloy of a semiconductor, Ge, and a metal, Ag, with bulk tendency to phase separation. The kinetics of growth at room temperature as well as the surface segregation of Ge have been investigated for the (111) orientation using Auger Electron Spectroscopy (AES) and Low Electron Energy Diffraction (LEED). The growth mode of Ge on Ag(111) is layer-by-layer like up to at least two layers. An unexpected ordered surface alloy forming a [Formula: see text] superstructure is observed during the growth at 1/3 germanium monolayer, followed by a p(7× 7) superstructure at one-monolayer coverage. The surface Ge segregation studied via both dissolution and segregation kinetics shows the particular stability of the ordered [Formula: see text] surface alloy.

Oxidation Kinetics of (Pb-In) Single-Phase Alloys

1989 ◽  
Vol 167 ◽  
Author(s):  
M.-X. Zhang ◽  
Y. A. Chang ◽  
V. C. Marcotte
Keyword(s):  
Melting Temperature ◽  
Oxidation Kinetics ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Room Temperature ◽  
Single Phase ◽  
Depth Profiling ◽  
Parabolic Kinetics ◽  
Logarithmic Law ◽  
Kinetics Of

AbstractThe solid state oxidation kinetics of Pb-In single-phase alloys were studied using AES (Auger Electron Spectroscopy) combined with sputter depth profiling. Samples containing 3, 30, 64 at% In were oxidized in air from room temperature up to 275 °C. At room temperature, the oxidation behavior for all three alloys was found to obey a direct logarithmic law. As the temperature is increased, the kinetics change from logarithmic to parabolic behavior. The transition between logarithmic and parabolic kinetics occurs between 150 °C and 175 °C for Pb-3 at% In alloy, and below 100 °C for Pb-30 at% In and Pb-64 at% In alloys. Using the solidius temperature as melting temperature of an alloy, the transition temperature for Pb-In alloys was observed to be approximately 70 – 75 % of the melting temperature.

Study of surface segregation of Si on palladium silicide using Auger electron spectroscopy

2004 ◽  
Vol 37 (22) ◽  
pp. 3140-3144 ◽  
Author(s):  
S Abhaya ◽  
G Amarendra ◽  
Padma Gopalan ◽  
G L N Reddy ◽  
S Saroja
Keyword(s):  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Segregation ◽  
Palladium Silicide

An Auger Electron Spectroscopic Study of the Diffusion of Sulfur and Carbon in α-Iron

1977 ◽  
Vol 31 (3) ◽  
pp. 210-213 ◽  
Author(s):  
W. E. Swartz ◽  
D. M. Holloway
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Boundary Diffusion ◽  
Carbon Migration ◽  
Sulfur Diffusion ◽  
Kinetics Of ◽  
Arrhenius Analysis

Auger electron spectroscopy has been employed to study the diffusion of sulfur and carbon in α-iron. In the temperature range 25 to 500°C carbon preferentially segregates to the surface. From 400 to 700°C sulfur segregates to the surface while carbon is thermally desorbed. An Arrhenius analysis of the sulfur diffusion data yields an activation energy of 14.5 kcal/mol, which is consistent with a grain boundary diffusion process. The kinetics of carbon migration is complicated by the thermal desorption which makes Arrhenius analysis impossible.

In situ high temperature X-ray diffraction study of the kinetics of phase separation in the uranium-plutonium mixed oxide (U0.55Pu0.45)O2-x

2014 ◽  
Vol 1645 ◽  
Author(s):  
Romain VAUCHY ◽  
Renaud.C. BELIN ◽  
Anne-Charlotte ROBISSON ◽  
Fiqiri HODAJ
Keyword(s):  
Phase Separation ◽  
Room Temperature ◽  
Mixed Oxides ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Fundamental Interest ◽  
X Ray ◽  
Uranium Plutonium ◽  
Kinetics Of

ABSTRACTUranium-plutonium mixed oxides incorporating high amounts of plutonium are considered for future nuclear reactors. For plutonium content higher than 20%, a phase separation occurs, depending on the temperature and on the oxygen stoichiometry. This phase separation phenomenon is still not precisely described, especially at high plutonium content. Here, using an original in situ fast X-ray diffraction device dedicated to radioactive materials, we evidenced a phase separation occurring during rapid cooling from 1773 K to room temperature at the rate of 0.05 and 2 K per second for a (U0.55Pu0.45)O2-x compound under a reducing atmosphere. The results show that the cooling rate does not impact the lattice parameters of the obtained phases at room temperature but their fraction. In addition to their obvious fundamental interest, these results are of utmost importance in the prospect of using uranium-plutonium mixed oxides with high plutonium content as nuclear fuels.

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