Nonlinear diffusion in excited Si crystals

¹ Department of Physics and Mathematics, Šiauliai University, Višinskio 25, 5400, Šiauliai, Lithuania
² Faculty of Physics, Vilnius University, Saulėtekio 9, 2040 Vilnius, Lithuania

Corresponding author: AYanavi@takas.lt

Received: 31 July 2003
Revised: 24 June 2004
Accepted: 24 September 2004
Published online: 21 December 2004

Abstract

We discuss the properties of the nonlinear diffusion equation for the case of diffusion in excited systems. The diffusion coefficient is directly proportional to the concentration of impurities and depends on the time in a special way. For the description of the excited systems, we used a special temperature function, which defined the time dependent diffusion coefficient and the Boltzmann's distribution of the excited vacancies or impurity atoms in solids. This model was used for approximation of very fast diffusion of metastable vacancies irradiated by soft X-rays in an excited Si crystal.