Charge transport and interdot coupling tuned by the tunnel barrier length in assemblies of nanoparticles surrounded by organic ligands
Résumé
Low-temperature electrical measurements were performed on arrays of metallic nanoparticles coated by alkylamines. The length of the alkyl molecules was varied (18, 12, and four carbons), while the size of the metallic nanoparticles was fixed at 10.3 nm. This allowed us to investigate the effect of interdot coupling on the electronic transport. We show that in the Coulomb-blockade regime, the temperature and bias dependence of the resistivity are governed by the length of the organic barriers and are well described by theories that consider inelastic cotunneling to be the main mechanism of interparticle transfer. Indeed, quantitative agreement between theory and experiments is obtained when considering the interparticle distance deduced from transmission electron microscopy with respect to the relevant characteristic energies (activation temperature and charging energy).