Cairo University

MTPR Journal



M. M. Saadeldin 1, Makram Ibrahim 2, M.Y. Helali 2
1 Physics Department, Faculty of Science, Cairo University
2 Department of Solar and Space Research, National Research institute of Astronomy
and Geophysics

Vol./Issue: 19 , id: 297

Three samples of ZnOvaristors doped with concentrations of copper oxide of 0.5 mol%, 1 mol%, and 3 mol%., with other impurities like carbon and iron.The traditional methods of preparing samples by mixing, drying, pressing and firing at 1100 ° C were used to obtain the samples in the form of dry solid discs. ZnO is a semiconductor ceramic material having a non-linear relationship between current and voltage, this property is used mainly to protect electric circuits from over-voltage risks on important parts of the electrical circuits such as various electronic components. The effects of the AC current frequency from 0 to 100 kHz and temperature from 20 to 170 ° C were studied on the dielectric constant, and electrical conductivity and comparisons of these parameters before and after laser irradiation are concluded. It was clear from the results that the carbon element which exists in all samples with different concentrations with the highest concentration in sample (2) has a big effect on the conductivity, the electrical conductivity of sample (2) highly increased than those of samples (1) and (3), while the iron component as an electrically conductive element is found by EDX only in sample (3) and in a very small concentration, and its effect on the electrical properties of this sample is thought to be negligible with respect to the effect of its high carbon content.