Electrical Conductivity and Current--Voltage Characteristics of Individual Conducting Polymer PEDOT Nanowires

We report the current--voltage (I-V) characteristics and electrical conductivity of individual template-synthesized poly(3,4-ethylenedioxythiophene) (PEDOT)
nanowires (190±6 nm in diameter and σ_RT= 11.2±2,Ω^-1cm^-1) over a wide temperature range from 300 to 10K. With lowering temperature, the I-V characteristics become nonlinear around 50K, and a clear Coulomb gap-like structure appears in the differential conductance (dI/dV) spectra. The
temperature dependence of the resistance below 70K follows ln R ∝ T^1/2, which can be interpreted as Efros--Shklovskii hopping conduction in the presence of a Coulomb gap. In addition, the influences of measurement methods such as the applied bias voltage magnitude, the two-probe and four-probe techniques used in the resistance measurements are also reported and discussed.