Despite the long-time use of space-charge electrets in various commercial applications, the mechanism of charge storage is still poorly understood. To study the energy distribution of deep traps, photostimulated discharge spectra of electron-beam and corona-charged polytetrafluoroethylene (PTFE), polyethylene terephthalate (PETP) and cellular polypropylene (PP) films were recorded for wavelengths between 200 and 400 nm. In addition, space-charge profiles were measured using the piezoelectrically generated pressure-step (PPS) method in order to monitor the detrapping process. Strong discharge currents of up to 15 pA/cm2 were found in PETP around the UV absorption edge near 310 nm. Initial results show a quantitative depopulation of near-surface charges, whereas only partial detrapping could be achieved for bulk charges. Three distinct trapping levels could be identified in PP films.
|Number of pages||4|
|State||Published - 2002|
|Event||11th International Symposium on Electrets - Melbourne, VIC., Australia|
Duration: Oct 1 2002 → Oct 3 2002
|Conference||11th International Symposium on Electrets|
|Period||10/1/02 → 10/3/02|