Trapping and electrical characterization of single core/shell iron-based nanoparticles in self-aligned nanogaps

TL;DR

This study demonstrates the fabrication and electrical characterization of single core/shell iron-based nanoparticles in nanogaps, revealing Coulomb blockade effects and extending nanoparticle device fabrication methods.

Contribution

It introduces a novel approach to trap and measure single iron-based nanoparticles in nanogaps using a cluster gun technique, avoiding issues of agglomeration from solution methods.

Findings

Coulomb blockade observed at low temperatures

Successful trapping of nanoparticles in nanogaps

Extension of fabrication techniques for single-electron devices

Abstract

We report on the fabrication and measurements of platinum-self-aligned nanogap devices containing cubed iron (core)/iron oxide (shell) nanoparticles (NPs) with two average different sizes (13 and 17 nm). The nanoparticles are deposited by means of a cluster gun technique. Their trapping across the nanogap is demonstrated by comparing the current vs voltage characteristics (I-Vs) before and after the deposition. At low temperature, the I-Vs can be well fitted to the Korotkov and Nazarov Coulomb blockade model, which captures the coexistence of single-electron tunneling and tunnel barrier suppression upon a bias voltage increase. The measurements thus show that Coulomb-blockaded devices can be made with a nanoparticle cluster source, which extends the existing possibilities to fabricate such devices to those in which it is very challenging to reduce the usual NP agglomeration given by a solution method.