By using Monte Carlo simulation of the deposition process and a mean-field theory model of the surface structure, experimental oblique-incidence optical reflectance difference signals from laser molecular beam epitaxy of Nb:SrTiO3 on a SrTiO3 substrate in ambient oxygen were successfully reproduced. It was found that during deposition the concentration of oxygen vacancies close to step edges was larger than that on flat terraces and remained stable. It was suggested that oxygen vacancies diffusing on the surface tended to accumulate near to step edges due to their slow in-diffusion rate there, and that this in-diffusion dominated the oxidation of as-deposited film.

In-Diffusion of Oxygen Vacancies Near Step Edges Dominates the Oxidation of Perovskite Films. X.Wang, Y.Fei, H.Lu, K.J.Jin, X.D.Zhu, Z.Chen, G.Yang: Journal of Physics - Condensed Matter, 2007, 19[2], 026206