Dielectric relaxation processes studies in oxygen- swift heavy ion irradiated Polyvinylidene fluoride (PVDF) thin film using TSDC measurement technique

摘要

Thermallystimulateddepolarizationcurrent(TSDC)measurementtechniquehavebeenusedtoinvestigatethedielectricrelaxationprocessesin75MeVOxygenswiftheavyion(SHI)irradiatedPolyvinylidenefluoride(PVDF).Thefilmsof20micro;mthicknesswereirradiatedwith75MeVOxygen-ionatdifferentfluence:1.0times;1010(1.0E+10),1.0times;1011(1.0E+11),5.63times;1011(5.63E+11),and5.68times;1012(5.68E+12)ions/cm2.Thermallystimulateddepolarization(TSD)currentmeasurementswerecarriedoutinthetemperaturerange30-1650Catdifferentpolarizationtemperature(Tp)andpolarizationfield(Ep).Theheatingrate(2ordm;C/min)andpolarizationtime(1h.)havebeenkeptconstantinallTSDCmeasurements.TSDCcharacteristicsof75MeVOxygen-ionirradiatedPVDFshowawelldefinedcurrentmaxima(termedasbeta;-peak)aroundthepolarizationtemperature(Tp)inthetemperatureregion70-1180C.TheTSDCspectraofhighTppoledsamplesalsoshowacurrentmaximumaround1200C(termedasalpha;-peak).Thebeta;-peakisattributedtothedipolarrelaxationprocess.Thealpha;-peakhasbeenascribedtothespacechargepolarizationprocessduetotheformationofnewdeeptrapsandinsomecasesnotablythosecorrespondingtolowvaluesofEpandTp,Thenumberofpeaksactuallyappearinginthesespectraandtheirlocation,heightandsharpnessaregovernedbydepolarizationparameters(Tp,Ep).Theactivationenergyandpre-exponentialfactorscorrespondingtobeta;-peakandalpha;-peakwerealsoestimatedatdifferentpolarizationtemperature(Tp)andpolarizationfield(Ep).