Simultaneous Assembly of van der Waals Heterostructures into Multiple Nanodevices

TL;DR

This paper presents a scalable method for fabricating van der Waals heterostructure nanodevices using liquid phase exfoliation combined with dielectrophoretic assembly, enabling simultaneous and efficient device production.

Contribution

It introduces a novel, scalable technique to assemble vdWH nanodevices from liquid exfoliated flakes using dielectrophoresis, preserving heterostructure properties.

Findings

The method allows simultaneous assembly of multiple nanodevices.

Properties of devices are comparable to those made by traditional methods.

The approach is suitable for large-scale vdWH applications.

Abstract

Van der Waals heterostructures (vdWH) are made of different two-dimensional (2D) layers stacked on top of each other, forming a single material with unique properties that differ from those of the individual 2D constituent layers, and that can be modulated through the interlayer interaction. These hetero-materials can be artificially made by mechanical stamping, solution processing or epitaxial growth. Alternatively, franckeite has been recently described as an example of a naturally-occurring vdWH that can be exfoliated down to nanometer thicknesses. Research on vdWHs has so far been limited to manually exfoliated and stamped individual devices. Here, a scalable and fast method to fabricate vdWH nanodevices from liquid phase exfoliated nanoflakes is reported. The transport and positioning of the flakes into localized submicrometer structures is achieved simultaneously in multiple devices via a dielectrophoretic process. The complex vdWH is preserved after dielectrophoresis and the properties of the resulting field-effect transistors are equivalent to those fabricated via mechanical exfoliation and stamping. The combination of liquid phase exfoliation and dielectrophoretic assembly is particularly suited for the study of vdWHs and applications where large-scale fabrication is required.