Transport properties and growth parameters of PdC and WC nanowires prepared in adual-beam microscope

Abstract

In this work we investigate the electrical transport properties and growth conditions oftungsten carbon (WC) and palladium carbon (PdC) nanostructures on Si substrates usinga focused ion beam and scanning electron microscope. In situ energy dispersive x-ray(EDX) characterizations reveal that electron-beam-induced WC and PdC nanostructuredepositions (EBID) show a lower metal concentration (below 3% atomic percentage)than in ion-beam-induced deposition (IBID) (above 20%). In the case of PdC thegrowth pattern and the Pd/C content were optimized by adjusting the depositiontemperature of the precursor material. In situ measurements of the resistivity ofthe nanostructures as a function of thickness reveal a minimum at a thickness∼200 nm. The lowest resistivity obtained for the PdC and WC structures is two orders ofmagnitude higher than the corresponding bulk values for pure Pd and W. The EBIDsamples show a non-metallic behaviour due to the low metal content. The temperature andmagnetic field dependence of the IBID structures reveal a behaviour similar to disorderedor granular conductors. The upper critical field and critical current density of theWC structures were measured below the superconducting critical temperatureof ∼5 K.