Anomalous temperature dependent transport through single colloidal nanorods strongly coupled to metallic leads

We report wiring of individual colloidal nanorods (NRs), 30-60 nm long by 3.5-5 nm diameter. Strong electrical coupling is achieved by electron beam induced deposition (EBID) of metallic lines targeting NR tips with nanometric precision. At T = 4 K many devices exhibit smooth I(V) curves with no sharp onset features, which remarkably fit a Fowler-Nordheim tunneling model. All devices exhibit an anomalous exponential temperature dependence of the form I approximately exp(T/T(0)). This irregular behavior cannot be explained by any hopping or activation model and is interpreted by accounting for the lowering of the NR conduction band due to lattice dilation and phonon coupling.