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

Heterojunctions composed of La(0.7)Ca(0.3)MnO(3) and 0.05 wt% Nb-doped SrTiO(3) 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 similar to 3.95 eV, which corresponds to the band-to-band excitation of electrons in Nb:SrTiO(3). From the internal photoemission, the height of Schottky barrier was determined as 1.64 eV. (c) 2008 American Institute of Physics.