Studies of the energy levels of point defects in perovskite oxides using conductivity methods
Prof. Igor Raevski,
Southern Federal University, Rostov-on-Don, Russia
In contrast to classical semiconductors, like Ge or Si, complex oxides of the ABO3 type (A and B-different metals) possessing the perovskite structure, contain a high concentration of the intrinsic point defects, mainly the vacancies in the O- , A- , or/and B-sublattices. These defects are usually called zero- dimensional defects. If the concentration of these defects increases, they can order, forming at first dislocations (one- dimensional defects) and then – crystallographic shear planes (two- dimensional defects). Doping of ABO3 perovskites by aliovalent ions usually leads mainly to the changes in the relative concentrations of intrinsic defects.
The main regularities of the energy band structure of ABO3 perovskites as well as the energies of the main types of intrinsic point defects will be discussed. Some results of the studies of the energy levels of point defects in perovskite oxides using conductivity methods (temperature dependence of dc conductivity, spectral dependence of the photoconductivity, non-equilibrium thermally stimulated conductivity) will be presented.