The linear diffusion equation was proposed to provide a macroscopic description of ionic mobility in nanostructures. This approach was demonstrated to account for diffusion processes in nanostructured titania-based films. The formulation of a classical diffusion inverse problem and the experimental determination of concentration profiles by Rutherford back-scattering spectrometry were used for the purpose. The model has allowed the measurement of the diffusion coefficient of W and Mo impurities in titania.

Diffusion-Equation Approach to Describe Ionic Mobility in Nanostructured Titania. V.Guidi, G.Martinelli, G.Schiffrer, A.Vomiero, G.D.Mea, E.Comini, M.Ferroni, G.Sberveglieri: Physical Review B, 2005, 72[15], 155401 (9pp)