|Ph.D Student||Zvi Rosenstock|
|Subject||Point Defect Distribution and the Electrical Transport|
Properties in Thin Films of Cu2O under Chemical
and Electical Potential Gradients
|Department||Department of Physics||Supervisor||Professor Emeritus Riess Ilan|
The main purpose of this work was to determine the I-V relations in cells of the forms M1|Cu2O|M2 and M1|CuO|M2. M1, M2 metals at room temperature, and to interpret them in view of the fact that the oxide is expected to be a mixed-ionic-electronic conductor (MIEC).
Both bulk and thin films were examined. In thin films higher currents can be applied and shorter relaxation times are observed. However, it is difficult to perform a true four-point measurement in thin films.
Since past and present measurements of I-V relations differ, part of the research aim was to examine whether different preparation methods produce different I-V relations results. Although the cell preparation methods were changed, the results remained different from those reported earlier, indicating that a previously undiscovered I-V relation type exists. The “old” interpretation claimed that the I-V relations are fixed by a Schottky barrier. We claim that they reflect an MIEC of a certain defect model placed between two ion-blocking electrodes. There are two types of acceptor defect in the cell, one of which is fixed and the other mobile. Both donate holes for the electronic current.
The claim of ionic motion is supported by experimental evidence of matter transport and morphological changes. It was observed that matter moved toward the negative electrode.