Charge Carriers on Insulating Surfaces: An Experimental Study

Surface charge has been extensively studied for decades, but the nature of charge carriers during charging and discharging processes is poorly understood. In this study, the surface potential decay characteristics at different thermal conditions are investigated to study charge carrier behavior on the corona-charged insulator surface. The results show that ions bind with surface atoms which might account for the residual charges on polytetrafluoroethylene (PTFE) and Al2O3-filled epoxy resin surfaces. Due to a high volume of conductivity, few charges are left on the silicone rubber (RTV) surface because the bonded ions could transport via volume conduction. A potential decay model is proposed considering different types of charge carriers, through which the effect of charge sources on the gas side, surface roughness, and voltage polarity can be explained.