Photoelectric response of Schottky barrier in La0.7Ca0.3MnO3∕Nb:SrTiO3 heterojunctions

Abstract

Heterojunctions composed of La0.7Ca0.3MnO3 and 0.05wt% Nb-doped SrTiO3 were fabricated using pulse laser deposition. The current-voltage characteristics of such heterojunctions can be described by tunneling with an effective Schottky barrier. These junctions showed significant response to ultraviolet and visible light. Band-to-band and internal photoemission were characterized by photoelectric experiments. A quantum efficiency of about 86% was observed at an incident energy of ∼3.95eV, which corresponds to the band-to-band excitation of electrons in Nb:SrTiO3. From the internal photoemission, the height of Schottky barrier was determined as 1.64eV.