Rectifying and photovoltaic properties of the heterojunction composed of CaMnO3 and Nb-doped SrTiO3 -: art. no. 053503

A heterojunction composed of CaMnO3 (CMO) and Nb-doped SrTiO3 (STON) was fabricated and its properties were studied and compared with La0.67Ca0.33MnO3/STON and LaMnO(3+)delta/STON p-n, junctions. This CMO/STON junction exhibits an asymmetric current-voltage relation similar to a p-n junction. The most remarkable discovery is that the magnetic state of the manganites has a strong impact on the rectifying behaviors. The diffusion voltage, which is the critical voltage for the current rush, shows a tendency to decrease/increase with the establishment of the antiferromagnetic/ ferromagnetic order in the manganites of the junction. Similar to other manganite p-n junctions, CMO/STON also exhibits a significant photovoltaic effect, and the maximum photovoltage is similar to2.2 mV under the illumination of similar to7 mW light (lambda=460 nm). A qualitative explanation is given based on an analysis on the band diagram of the junctions. (C) 2005 American Institute of Physics.