Influence of swift heavy ions irradiation on carrier transport of polyimide films

In the present paper we report results concerning the influence of Swift Heavy Ions (SHI) irradiation on the mechanisms of electron transport in 22 μm thick polyimide (PI) films. The PI films were subjected to SHI irradiation with fluences 1×10⁸ ions/cm² . The following etching of latent tracks with the 13% NaOCl solution resulted in the formation porous PI membranes (PPI). It is shown that the formation of carboxyl (COOH) moieties on the internal surfaces of the formed pores results in creation of highly-conductive layers along the pores. Experimental and modelling studies of transversal I-V characteristics in Cu/PI/Cu and Cu/PPI/Cu structures in the temperature range 240 - 300 K have shown that the low-temperature carrier transport is due to the formation of space charge limited current and described by the improved Mott-Gurney law developed in Mark-Helfrich model. (authors)