Coulomb-blockade transport in quasi-one-dimensional polymer nanofibers

We report the low temperature current-voltage (I-V) characteristics studies in quasi-one-dimensional conducting polymer nanofibers. We find a threshold voltage Vₜ below which little current flows at temperatures below 30--400.3em0exK. For V>Vₜ current scales as (V∕Vₜ-1)^ζ where ζ~1.8--2.1 at high biases. Differential conductance oscillations are observed whose magnitude increases as temperature decreases below 100.3em0exK. We attributed the observed low temperature I-V behavior to Coulomb-blockade effects with a crossover to Luttinger liquidlike behavior at high temperature. We demonstrate that at low temperatures such a doped conjugated polymer fiber can be considered as an array of small conducting regions separated by nanoscale barriers, where the Coulomb-blockade tunneling is the dominant transport mechanism.