Good rectifying characteristic in p–n junctions composed of La0.67Ca0.33MnO3−δ/Nb–0.7 wt %-doped SrTiO3

Simple p–n junctions have been fabricated using a simple heteroepitaxial structure of La0.67Ca0.33MnO3−δ/Nb-doped SrTiO3. In such junctions, the La0.67Ca0.33MnO3−δ exhibits semiconductor behavior due to oxygen deficiency, whereas the Nb–0.7 wt %-doped SrTiO3 shows a metal behavior. These junctions demonstrate good rectifying characteristic in a wide temperature range from 5 to 350 K. An intriguing observation is that the rectifying behavior is nearly independent of temperature.