Chemistry, physics, and engineering of electrically percolating arrays of nanoparticles: a mini review

Abstract

Nanoparticles and their arrays do not obey Ohm's law, even when the particles are made of metal, because of their small size. The non-Ohmic behavior is due to their low capacitance that allows (local) storage of charge at the single electron level to pose a substantial barrier to the passage of current at bias, V, below a threshold voltage, VT. The VT is inversely proportional to the size of the particle. For a typical <10 nm particle, the electrostatic barrier energy of the particle due to charging by a single electron is significantly larger compared to the thermal energy, affecting a substantial Coulomb blockade. The signature of the single electron effect is a highly non-linear current-bias behavior characterized by a critical point at VT with a subsequent rise in current that scales as (V/VT − 1)ζ, where ζ ≥ 1 is the critical exponent. We review the fabrication chemistry, device physics, and engineering applications of nanoparticle-based Single Electron Devices with architectures ranging from a single nanoparticle to arrays in one and two dimensions. The arrays are particularly interesting due to their natural integrability with microelectronic circuitry and robust single electron behavior at room temperature. These features open doors to a broad range of potential applications, such as chemical sensors, biomedical devices, data storage devices, and energy devices.