Effect of oxygen activity on chromium segregation in Cr-doped TiO2 single crystal

Abstract

The present work determined the effect of chromium segregation on surface and near-surface composition of Cr-doped TiO2 (0.05 at.% Cr) after annealing in oxidising and strongly reducing environments at 1,073 and 1,273 K. The segregation-induced depth profiles were determined by secondary ion mass spectrometry (SIMS). It was observed that annealing in oxidising conditions [p(O2) = 105 Pa] and reducing conditions [10−11 Pa > p(O2) > 10−15 Pa] results in an enrichment and depletion of the surface layer in chromium, respectively. The observed effects may be used for tailoring the surface and near-surface composition in order to impose desired properties. © 2015 Springer Nature Switzerland AG.