Temperature dependence of tunneling current in Pt/Nb:SrTiO3 Schottky junction

We investigate temperature-dependent electrical properties of Pt/Nb:SrTiO3 Schottky junctions by measuring current–voltage and capacitance–voltage curves at various temperatures (20 K–300 K). Interestingly, the Schottky junctions have shown different temperature dependences of resistance according to the polarity of bias voltage: insulating behaviors are displayed in the positive bias branch, while metallic behaviors are observed in the negative bias branch. These behaviors can be ascribed to Schottky barrier modulation that arises from the temperature and field dependences of dielectric permittivity of SrTiO3. The modulation of the barrier profile determines anomalous tunneling current in the negative bias branch as a function of temperature. These comprehensive analyses could not only reveal the rich physics of the Pt/Nb:SrTiO3 Schottky junction but also enhance our understanding for high dielectric materials.