Electrical transport and AFM microscopy on V2O5−X–polyaniline nanorods

With the aim of obtaining nanodevices as rectifiers or transistors, we obtained (V2O5−X–polyaniline) nanorods, as it has been previously described, where the polymerisation of aniline is favoured by reduction of V2O5. We measured the I(V) characteristics and electrical resistance in the temperature range from RT to 140 K, on nanorods (<20-nm thick and 300–800-nm long) deposited on a sample holder, where six inter-digitated metallic contacts were previously made by lithography. Using AFM microscopy in tapping mode, we examined the samples and selected some that contacted either two or four wires. In both cases, the I(V) characteristics were clearly nonlinear and symmetrical with respect to both axes. Electrical conductivity values at RT are near 10–1 (S/cm). After that, a rectifying effect could be obtained if we were able to displace the characteristics on the axis. When the temperature was lowered below 140 K, electrical resistivity increased abruptly.