Composite conduction in ion-implanted polymers

Abstract

The temperature dependence of the dc conductivity for polyamide-imide films, implanted with 50 keV As ions to different fluences, has been studied. Our high-resolution data reveal a two-component conductivity that depends on both one-dimensional variable range hopping (VRH) and three-dimensional VRH. For low fluence levels (5×1015 ions/cm2), the one-dimensional VRH is dominant while at higher fluences (1×1017 ions/cm2), the three-dimensional VRH dominates. These materials become highly disordered and form hard carbon materials along the ion track. The conductivity may be explained by 1D VRH along the ion track at low fluences while at higher fluences, regions of carbon rich material form three-dimensional structures where 3D VRH exists. This rather simple model and its composite conductivity can explain the exact curvature of the temperature dependent conductivity, while single VRH models and percolation models cannot.

Magnetoresistive Effect in PET Films with Iron Nanoparticles Synthesized by Ion Implantation

“…a negative temperature coefficient of resistance, that represents a well-known behavior for ion-implanted polymers [8,14]. One of these dependences is presented in Fig.…”

“…The dominant mechanism of charge carrier transport in implanted polymer layers is typically described by VRH. The temperature dependence of conductance in this case is defined by well-known equation [14] …”

Modification of the electrical properties of polyimide by irradiation with 80 keV Xe ions

“…Ion irradiation is an effective method for modifying the surface properties (including mechanical, optical, electrical, magnetic, etc.) of polymer membranes [1][2][3][4]. Conducting nanoparticles interacting through a dielectric polymer medium by various electron conduction mechanisms constitute materials that translate topological changes into changes in physical properties, providing a basis for strain sensing, pressure sensing, and the fabrication of electroresponsive materials [5].…”

Plasma immersion ion implantation on polymers

“…The change in conductivity of ion-implanted polymers also depends primarily on implantation dosage level [35,84]. The models used in examining the conduction mechanism includes the quasi-one-dimensional variable range hopping [85] or tunneling between metallic particles embedded in an insulating medium. Both the models predict identical expression for the dc electrical conductivity.…”