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TSDC measurements and analysis of pristine and 100 MeV Ag- swift heavy ion irradiated Polyvinylidene fluoride (PVDF) thin film

DINESH SINGH RANA1,*

Affiliation

  1. Department of Instrumentation, Kurukshetra University, Kurukshetra, India

Abstract

Thermally stimulated depolarization current (TSDC) measurements have been used to investigate the various dielectric relaxation processes in pristine and 100 MeV Ag swift heavy ion (SHI) irradiated Polyvinylidene fluoride. The films of 20 μm thickness were irradiated with 100 MeV Ag-ion at fluence; 1.8 X1011 ions/cm2. Thermally stimulated depolarization (TSD) current measurements were carried out in the temperature range 300 –165 0C at different polarization temperature (Tp) and polarization field (Ep). The heating rate (2 ºC/min) and polarization time (1 hrs.) have been kept constant in all TSDC measurements. TSDC characteristics of pristine show a well defined current maxima (termed as β-peak) around the polarization temperature (Tp) in the temperature region 700-120 0C, another current maxima around 162 0C (termed as δ-peak) and in certain cases a kink is also observed around 135 0C. The β-peak is attributed to the dipolar relaxation process and δ-peak is associated with the premelting of the sample. The number of peaks actually appearing in these spectra and their location, height and sharpness are governed by depolarization parameters (Tp, Ep). The TSDC characteristics of 100 MeV Ag-ion irradiated PVDF samples (fluence: 1.8×1011 ions/cm2) in the temperature range 300-165 0C almost follow the similar pattern as in case of pristine samples except one more TSD current maxima around 120 0C, termed as α-peak (α relaxation) ascribed to the space charge polarization process owing to the formation of new deep traps and in some cases notably those corresponding to low values of Ep and Tp, an additional shoulder designated as γ has also been observed around 55 0C. The activation energy and pre-exponential factors corresponding to β-peak and α-peak were also estimated at different polarization temperature (Tp) and polarization field (Ep)..

Keywords

PVDF, TSDC, SHI, Activation energy (U), Pre-exponential factors(τ0).

Citation

DINESH SINGH RANA, TSDC measurements and analysis of pristine and 100 MeV Ag- swift heavy ion irradiated Polyvinylidene fluoride (PVDF) thin film, Optoelectronics and Advanced Materials - Rapid Communications, 6, 5-6, May-June 2012, pp.642-647 (2012).

Submitted at: March 22, 2012

Accepted at: June 6, 2012