Coulomb gap variable range hopping in graphitized polymer surfaces

The conductivity of several polymers was investigated after low-energy ion irradiation. The enhancement of conductance induced by the ions is discussed in terms of graphitization. We have found that the transport in the graphitized surfaces can be consistently described in terms of the 2D Coulomb gap variable range hopping theory. However, analyzing the properties of the pre-exponential factor in the temperature dependence of conductance and current–voltage characteristics we found several contradictions with existing theories.