title: Tunneling mechanism and contact mechanics of colloidal nanoparticle assemblies.
abstract: Nanoparticle assemblies with thiol-terminated alkyl chains are studied by conducting atomic force microscopy (c-AFM) regarding their use as strain gauges for touch-sensitive panels. Current-force spectroscopy is used as a characterization tool complementary to the macroscopic setup since it allows a bias to be applied to a limited number of junctions, overcoming the Coulomb blockade energy and focusing on the contact electromechanics and the transport mechanism across the ligand. First, transition voltage spectroscopy is applied with varying force to target the underlying tunneling mechanism by observing whether the transition between the ohmic and exponential current-voltage behavior is force-dependent. Secondly, current-force spectroscopy in the ohmic range below the transition voltage is performed. The current-force behavior of the AFM probe in contact with a nanoparticle multilayer is associated with the spread of force and current within the nanoparticle lattice and at the level of adjacent particles by detailed contact mechanics treatment. The result is twofold: concerning the architecture of sensors, this work is a sample case of contact electromechanics at scales ranging from the device scale down to the individual ligand molecule. Regarding transport across the molecule, the vacuum tunneling mechanism is favored over the conduction by coherent molecular states, which is a decision-making aid for the choice of ligand in applications.
authors: Institut d'Electronique, Microelectronique et Nanotechnologie, CNRS UMR 8520, CS60069, F-59652 Villeneuve d'Ascq Cedex, France.
authors: Moussa
authors: M
authors: Biaye
authors: Ewa
authors: E
authors: Zbydniewska
authors: Thierry
authors: T
authors: Mélin
authors: Dominique
authors: D
authors: Deresmes
authors: Guillaume
authors: G
authors: Copie
authors: Fabrizio
authors: F
authors: Cleri
authors: Neralagatta
authors: N
authors: Sangeetha
authors: Nicolas
authors: N
authors: Decorde
authors: Benoit
authors: B
authors: Viallet
authors: Jérémie
authors: J
authors: Grisolia
authors: Laurence
authors: L
authors: Ressier
authors: Heinrich
authors: H
authors: Diesinger