Transport properties of Mo6S3I6 nanowire networks

We present measurements of resistivity on Mo6S3I6 nanowire networks under different conditions. The room-temperature values of conductivity of as-grown nanowire networks are on the order of σ300K=0.04S∕m and show linear current-voltage characteristics, indicating that—in agreement with band structure calculations—there is a finite density of states at the Fermi level. The conductivity of pristine samples is thermally activated, closely following three-dimensional variable range hopping (VRH) behavior of the form σ=σ0exp−(T0∕T)β, where β=1∕4. Removal of interstitial iodine from the network by annealing in a vacuum gives rise to a cross over to one-dimensional VRH with β=1∕2 and a concurrent increase in room-temperature conductivity. The introduction of water vapor leads to a decrease in conductivity and reveals that the resistivity of the network is sensitive to interstitial water molecules.