UV induced composition changes in SrTiO3 and their consequences

Wide band gap semi-conductors such as SrTiO3 (STO) have attracted high interest for photoelectrochemical water splitting and as part of high temperature photovoltaic cells. However, the impact of UV irradiation on the composition (e.g. the oxygen content) of STO and Fe doped STO (Fe:STO) at elevated temperatures has hardly been studied. In Fe:STO, UV exposure causes an enhanced oxygen incorporation rate and, therefore, a decreased oxygen vacancy concentration in air at elevated temperatures. In this contribution we discuss such bulk stoichiometric changes in terms of optical and electrochemical (e.g. AC conductivity) properties. Moreover, the kinetics behind the incorporation were examined, more precisely chemical diffusion coefficients obtained from UV/VIS measurements were calculated.