Equilibrium Segregation to Free Surface:Kinet ics and Experiment
CAO Ze-xian1,2, Ralf Mueller2, WANG En-ge1, NIE Yu-xin1
1State Key Laboratory for Surface Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080
2Department of Physics, University Kaiserslautern, 67653 Kaiserslautern, Germany
Equilibrium Segregation to Free Surface:Kinet ics and Experiment
CAO Ze-xian1,2;Ralf Mueller2;WANG En-ge1;NIE Yu-xin1
1State Key Laboratory for Surface Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080
2Department of Physics, University Kaiserslautern, 67653 Kaiserslautern, Germany
Abstract： Fick's first law is modified with an additional term df(x)/dx to describe the segregation phenomenon, f(x) is a local, analytical function related to the depth profile at equilibrium. It thus can be determined experimentally by depth profiling technique. Segregation starting in an initially homogeneous solid is described by an inhomogeneous diffusion equation on the half-infinite domain. Segregation with and without formation of overlayer suggests different boundary conditions. The solution for the Ansatz f(x) = as exp(-x/ds) is in perfect agreement with experimental results on sulphur segregation to the surface of titanium. Independent from the detailed kinetics, activation energy can be inferred from the surface concentration evolution under different temperatures. For sulphur segregation in titanium, Eact = 718 meV/atom.
(Chemical composition analysis, chemical depth and dopant profiling)
引用本文:
CAO Ze-xian;Ralf Mueller;WANG En-ge;NIE Yu-xin. Equilibrium Segregation to Free Surface:Kinet ics and Experiment[J]. 中国物理快报, 1999, 16(5): 364-366.
CAO Ze-xian, Ralf Mueller, WANG En-ge, NIE Yu-xin. Equilibrium Segregation to Free Surface:Kinet ics and Experiment. Chin. Phys. Lett., 1999, 16(5): 364-366.
1999, Vol. 16 
