Gating of Enhanced Electron-Charging Thresholds in Self-Assembled Nanoparticle Films

Abstract

Films of butanedithiol interconnected nanoparticles can exhibit a percolation-driven insulating to metal transition. To explore properties of materials with interpolating behavior, we have measured conductance of these films with systematically varying thickness. Films below a certain threshold coverage exhibit thermally assisted conductance and conductance suppression near zero bias indicative of single-electron-charging barriers. In analogy with semiconductors, we show that these films permit transistor-type gating of film conductivity.

Quantitative Visualization of Topology and Morphing of Percolation Path in Nanoparticle Network Array Exhibiting Coulomb Blockade at Room Temperature

“…Metallic nanoparticle arrays are an important class of nanomaterials due to their electronic properties, such as free-electron plasmon oscillations and low capacitance. The plasmon oscillation resonance in the optical range provides a convenient near-field optical arrangement for developing highly sensitive optical devices to probe chemical environments, such as by reflectivity (surface plasmon resonance) − and spectroscopy (surface-enhanced Raman scattering). − Owing to low charging energy, typically ∼60 meV for a 10 nm metal particle capped with organics allows for the possibility of fabricating a transistor where the current can be gated by a Coulomb blockade caused by single-electron charging. , In a nanoparticle array, the effect is enhanced due to multiple Coulomb blockades along the percolation path to obtain non-Ohmic behavior where the current ( I ) and applied bias ( V ) exhibit a threshold, V T , given as I ∼ ( V – V T ) ζ , where ζ is a critical exponent. − The conduction gap, V T , can be gated to form a single-electron transistor …”

“…10−12 The conduction gap, V T , can be gated to form a single-electron transistor. 13 The nonlinear (i.e., non-Ohmic) electrical behavior of a metallic nanoparticle array at cryogenic temperatures is well understood in terms of variable range hopping, i.e., an Efros− Shklovskii-like law, mediated by the cotunneling phenomenon 14 and stationary offset charge from the substrate (referred to as quenched charge distribution). 11,15 At room temperature, the hopping length should vanish to a single particle, 16 and the Coulomb blockade may be overcome due to high-energy conduction electrons, i.e., the tail of the Fermi−Dirac distribution.…”

Electrochemical properties of ferrocenylalkane dithiol-gold nanoparticle films prepared by layer-by-layer self-assembly

“…Combined, strong quasi-one dimensional transport, percolation effects and scattering in turn can generate -even in macroscopic films -some very dramatic phenomena that are typically associated with nanoscale systems. Examples include single electron charging [24,76] and quantum interference effects [25]. Studies to explore these effects are on-going in our group.…”

Novel Crown Ether-Capped Cationic Gold Nanoclusters in an Aqueous Medium and Their Single-Electron Charging Features

“…The molecular capacitor character of monolayer-protected nanoclusters (MPCs) demonstrates the unique electron-transfer chemistry of these nanosized particles, which makes them potential building blocks for nanoelectronic circuit components such as field-effect transistors, molecular switches, and resonant tunneling diodes. − Water-dispersible metal nanoclusters have promising applications as sensors and molecular markers and, in particular, in biological applications such as biolabeling and drug delivery. − The controlled synthesis of metal nanoclusters by steric stabilization is a widely discussed method in the literature, though it is less well understood as compared with electrostatic stabilization of colloidal particles. − However, the combined effect of both steric and electrostatic stabilization of metal nanoclusters is a less explored area in current research.…”