Characterization of the Schottky barrier in SrRuO3∕Nb:SrTiO3 junctions

Internal photoemission spectroscopy was used to determine the Schottky barrier height in rectifying SrRuO3∕Nb-doped SrTiO3 junctions for 0.01 and 0.5wt% Nb concentrations. Good agreement was obtained with the barrier height deduced from capacitance-voltage measurements, provided that a model of the nonlinear permittivity of SrTiO3 was incorporated in extrapolating the built-in potential, particularly for high Nb concentrations. Given the generic polarizability of perovskites under internal/external electric fields, internal photoemission provides a valuable independent probe of the interface electronic structure.