Influence of a few parameters on thermostimulated depolarization currents flowing on a fused silica surface

Interdigitated comb-shaped electrodes printed on an insulating solid surface provide a tool very suitable to put in evidence the electrical properties variations occuring when this surface interacts with the gaseous atmosphere in which it is placed. These changes in dielectric behaviour can be observed with this electrode pattern either measuring electrical conductivity /1/, or recording Surface Thermostimulated Depolarization Current (STDC) spectra /2/. We will briefly recall this latter method procedure. After a conditioning treatment which will be defined later, a polarization voltage Vp was applied to the electrodes during a time tp at at temperature Tp. Afterwards, the sample was cooled to −150°C then polarization voltage was cut off and the electrodes were linked together across an electrometer connected to a graph plotter. Depolarization current Id was recorded while the sample temperature was increased slowly at a constant rate. We shall report in this paper how STDC spectra recorded on fused silica specimens can be influenced by a few parameters.