Identification of Mott insulators and Anderson insulators in self-assembled gold nanoparticles thin films

Abstract

How the interparticle tunnelling affects the charge conduction of self-assembled gold nanoparticles is studied by three means: tuning the tunnel barrier width by different molecule modification and by substrate bending, and tuning the barrier height by high-dose electron beam exposure. All approaches indicate that the metal-Mott insulator transition is governed predominantly by the interparticle coupling strength, which can be quantified by the room temperature sheet resistance. The Hubbard gap, following the prediction of quantum fluctuation theory, reduces to zero rapidly as the sheet resistance decreases to the quantum resistance. At very low temperature, the fate of devices near the Mott transition depends on the strength of disorder. The charge conduction is from nearest-neighbour hopping to co-tunnelling between nanoparticles in Mott insulators whereas it is from variable-range hopping through charge puddles in Anderson insulators. When the two-dimensional nanoparticle network is under a unidirectional strain, the interparticle coupling becomes anisotropic so the average sheet resistance is required to describe the charge conduction.

Metal nanoparticle film–based room temperature Coulomb transistor

“…In semiconductor-nanoparticle arrays, the coherence of the superlattice determines whether Coulomb charging or band-like transport governs the electrical transport ( 25 ). In extended metallic nanoparticle films, the presence of the effect of Coulomb blockade can be extracted by analysis of the transport characteristics ( 26 , 27 ). To include high-quality nanoparticles as a two-dimensional (2D) array into an electrical device, we use a unique combination of both top-down and bottom-up techniques.…”

Anderson Insulators in Self-Assembled Gold Nanoparticles Thin Films: Single Electron Hopping between Charge Puddles Originated from Disorder

“…(2). [19] At lower temperatures, disorder may result in the charge co-tunneling in the molecule junctions, producing a transport resembling the E-S VRH. Before analyzing our data, we should look if Eq.…”

“…Nevertheless, they can be identified from the metallic phase with the dramatically upturning resistance and large negative magnetoresistance at very low temperatures. [19] As we have seen in 2D systems, the metallic phase could be overwhelmed by Anderson localization so a careful examination is needed. In this paper we report measurement results on charge transport in assembly of Au NPs with a few layers.…”

Thermoelectric Properties of Composite Nanoparticle Array with Protoporphyrin Molecule Junctions

“…[1] The symmetrical electrodes were 20nm/50nm Cr/Au deposited on glass substrate (Corning). Highpurity Cu wires were adhered respectively on two pairs of electrodes by silver filled electrically conductive adhesives.…”

“…For a moleculenanoparticle (NP) composite array, its properties may strongly depend on the molecules on/between NPs. For instance, the resistance of NP composite film sensitively change with the length of surface molecules, [1,2] and could be applied to vapor sensors. [3] In this report, we show a homemade system to measure thermoelectric properties of protoporphyrin molecule junctions in molecule-NP composite array.…”