Rectifying and photovoltaic properties of the heterojunction composed of $CaMnO3$ and Nb-doped $SrTiO3$ Available to Purchase

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 $LaMnO3+δ$/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 $∼2.2mV$ under the illumination of $∼7mW$ light $(λ=460nm)$⁠. A qualitative explanation is given based on an analysis on the band diagram of the junctions.