Effect of Sintering Atmosphere on the Electrical and Chemical Characteristics of the Grain Boundaries of SrTiO3 Ceramics Prepared from Semiconducting Powders

초록

The relation between the defect chemistry and the electrical characteristics of the grain boundaries in polycrystalline SrTiO3 ceramics, which were prepared from semiconducting powders by pressureless sintering techniques, was investigated. The charge density of the excess negative layer of the grain boundaries varied from 1 C/cm2 to 1.26 C/cm2 depending on the type of sintering atmospheres; these values were calculated from chemical composition at grain boundaries. The threshold voltage, grain boundary resistance and barrier height of the ceramics increased from 6.40 V/cm, 2.70 Kohm and 0.08 eV to 1000 V/cm, 3050 kohm and 10.9 eV with varying sintering atmosphere from nitrogen-hydrogen to air, respectively. The electrical and chemical features of semiconducting ceramics can be controlled by pressureless sintering in various sintering atmospheres.