Self-assembled contacts to nanoparticles using metallic colloidal spheres

TL;DR

This paper presents a simple, scalable method for fabricating nanoscale electronic devices using self-assembled metallic colloidal spheres as electrodes, enabling controlled tunneling contacts with nanoparticles.

Contribution

The authors introduce a novel assembly technique that uses metallic colloidal spheres to create nanometer-scale electrodes for electronic devices, simplifying fabrication.

Findings

Device resistance can be tuned with a gate electrode.

Measured current shows Coulomb blockade effects.

Assembly method is scalable and inexpensive.

Abstract

The spontaneous assembly of particles in suspension provides a strategy for inexpensive fabrication of devices with nanometer-scale control, such as single-electron transistors for memory or logic applications. A scaleable and robust method to form electrodes with the required nanometer-scale spacing, however, remains a major challenge. Here, we demonstrate a straightforward assembly approach in which metallic colloidal spheres serve as the electrodes. The devices are formed by assembly in suspension followed by deposition onto a patterned substrate. The key to this approach is that the inter-electrode (inter-sphere) spacing is spontaneously set to allow tunneling contact with a single layer of nanoparticles. The measured current exhibits the Coulomb blockade owing to the small size and large electrostatic charging energy of the nanoparticles. We show that the device resistance can be tuned by means of a gate electrode. Our results demonstrate an altogether new approach to inexpensive and large-scale fabrication of electronic devices such as transistors with nanometer-scale features.