Surface segregation of bulk oxygen on oxidation of epitaxially grown Nb-doped SrTiO3 on SrTiO3(001)

We studied the epitaxy of 10 mol % Nb:SrTiO3 on a SrTiO3(100) substrate under an interrupted pulsed-laser-deposition condition. By monitoring the recovery behaviors of reflection high-energy electron diffraction intensity and an optical reflectance difference signal from the growth surface, we observed that, at temperatures above 630 °C, the oxidation of an as-deposited Nb:SrTiO3 monolayer was achieved by the diffusion of oxygen vacancies in the monolayer into the substrate.