Photoresponse of the Schottky junction Au/SrTiO3:Nb in different resistive states

A systematic study on photovoltaic effects has been performed for the Schottky junction Au/SrTiO3:0.05 wt %Nb, the resistance of which can be tuned, by applied electric pulses, between ∼1 and ∼200 MΩ. It is found that, despite the great change in junction resistance, the photocurrent across the junction is constant when the power and wavelength of incident light are fixed. The corresponding Schottky barrier, deduced from the photoresponse data is ∼1.5 eV, independent of junction resistance. This result suggests the invariance of the interfacial barrier during resistance switching and the occurrence of filamentary conduction channels.