CHARGE-TRANSPORT IN THIN-FILMS OF POLYANILINE - VARIABLE-RANGE-HOPPING IN A PARABOLIC QUASI-GAP

We report a study of charge transport in thin, conducting polyaniline films, fabricated by using the Langmuir-Blodgett or layer-by-layer sel f-assembly techniques. The conductivity was studied as a function of f ilm thickness, temperature and electric field, all the results being c onsistent with theoretical models for variable-range hopping in a para bolic quasi-gap. Furthermore, the films showed a small n-type field ef fect which can be simply explained by assuming that the parabolic quas i-gap is a Coulomb gap.