Dielectric behavior of As+ implanted polyethylene terephthalate films

The dielectric behavior of As⁺-implanted polyethylene terephthalate (PET) films fabricated by 180 keV, ion implantation has been studied. It is demonstrated that PET films after being subjected to As implantation, exhibit a new dielectric relaxation phenomenon as well as large change in electric conductivity. The relaxation frequency, that is the frequency for the occurrence of the dielectric loss peak, increases with increasing As⁺ fluence. Both the relaxation frequency and the electric conductivity are proportional to exp[-(T ₀/T)^1/2] for the range of temperatures and electric fields in this investigation. The loss tangent peak reaches 0.5 for As⁺ fluence of 5×10¹⁶ cm^-2. The results indicate that ion implantation causes the material to become a granular, consisting of many discrete conducting domains, and that the electric transport is due mainly to electron tunneling between such discrete conducting domains. On the basis of this transport mechanism a model has been derived to explain the dielectric behavior of ion-implanted materials