Single-Electron Tunnelling Observed At Room Temperature by Scanning-Tunnelling Microscopy

Abstract

Ultrasmall ( S 5 nm in lateral diameter) double-barrier tunnel junctions have been realized using a scanning tunnelling microscope, and an optimized metal particle-oxide-metic substrate system. Three electrical transport effects, all in good agreement with the semi-classical theory of single-electron tunnelling, have been found at room temperature: the Coulomb gap, the Coulomb staircase and zero-bias conductance oscillations as a function of tip-particle distance.

Metal Clusters and Colloids

“…Such odd±even effects have been predicted to influence thermodynamic properties, which has recently been demonstrated by measuring the electronic specific heat C el and the electronic susceptibility w el of a series of Pd clusters. [7] The five-, seven-, and eight-shell clusters Pd 561 phen 36 O 200 (Pd5), Pd 1415 phen 54 O 1100 (Pd7), and Pd 2057 phen 78 O 1600 (Pd8), and a Pd colloid of 15 nm diameter (Pd coll ) were used for C el and w el measurements at temperatures <2 K. Whilst the specific heat of bulk palladium is proportional to the temperature, the investigated clusters show considerable deviation from the bulk behavior below 1 K. The most pronounced effect is observed for Pd5, the smallest of the investigated particles, and, as expected, decreases with increasing size.…”

Preparation of arrays of metallic nanoparticles exhibiting coulomb blockade at room temperature: an approach based on the self‐organization of metal‐loaded diblock‐copolymers

“…The experimental data can be nicely fitted by Coulomb blockade theory (dotted curve). 10,11 The fitting parameters for this measurement are: The shape of the I-V curves, however, differs as there is a certain fluctuation in the various parameters influencing the blocking effect, like capacitances and coupling resistances.…”

Metal-cluster compounds: Model systems for nanosized metal particles

“…11 Studies with scanning tunneling microscopy (STM) of metal-cluster molecules dispersed on substrates have already been performed by a group in Germany, and by Professor H. van Kempen and co-workers at KUN (Nijmegen). Apart from imaging of the clusters, several other interesting issues are at stake in the tunneling processes between the STM electrodes through a single metal-cluster molecule.…”