Modeling the sequential electric field assisted diffusion into glass of two ion species

The sequential electric field assisted diffusion of two ion species into glass is modeled in this work. Using standard assumptions, two coupled nonlinear drift-diffusion equations are derived for the ion concentration distributions. These equations are solved numerically for the case where the two ion species each have a lower mobility than the indigenous sodium ions in the glass. It is shown that stationary state distributions form if the final species injected into the glass is the less mobile of the two. Analytical expressions are derived for the stationary state distributions. A possible application in integrated optics involving Ag+ and Cu+ ion diffusion is considered.