|M.Sc Student||Kalaev Dima|
|Subject||Effect of Motion of Donors and Acceptors on the Current-|
Voltage Relations in Simple
|Department||Department of Physics||Supervisor||Professor Emeritus Ilan Riess|
|Full Thesis text|
We study the properties of solid materials that show ionic conductivity on top of electronic one. The electronic conductivity originates from electrons in the conduction band, holes in the valence band or electron hopping in an impurity or native defect band. The ionic motion is facilitated by defects in the crystalline structure. The materials that have both ionic and electronic conductivity are called- mixed ionic electronic conductors or shortly, MIECs. The MIECs can be viewed at as doped semiconductors with highly mobile dopants.
The I-V relations of MIEC devices of the form metal1|MIEC|metal2 exhibit interesting nonlinear shapes and, in some cases, show switching. We have calculated the I-V relations and defects distribution under steady state conditions for two cases of such devices. First both electrons and holes contribute to the MIECs conductivity. The electrodes are assumed to be ion blocking. In the second case the electrodes are not blocking. The calculation starts with the transport, continuity and Poisson equations, which form a set of differential equations with boundary conditions (BVP). The BVP is solved numerically for a wide range of parameters. The key result is that rectification in the presence of mobile acceptors or donors may occur not only when depletion exists at the metal|MIEC contact under equilibrium.