Interfacial layer in La0.95Tb0.05MnO3/Nb-SrTiO3 heterojunction

In this work, we report the electrical transport and dielectric properties of the La0.95Tb0.05MnO3/Nb-doped SrTiO3 heterojunction fabricated by laser molecular beam epitaxy. The sample shows a grain-boundary like current-voltage (I-V) behavior and linear C−2-V (C is capacitance) behavior in both forward and backward biases. These results are interpreted in terms of an interfacial layer which absorbs electrons from the film and substrate forming back-to-back Schottky barriers. Charge carriers trapped by the interfacial layer are found to follow an electric-field activated law. This work demonstrates the presence of the interfacial layer and indicates that this layer can play an active role in determining the properties of the heterojunction.