The hot pick-up technique for batch assembly of van der Waals heterostructures

TL;DR

This paper introduces a rapid batch fabrication technique for van der Waals heterostructures, achieving high yield and enabling complex layered 2D material devices with improved interface quality.

Contribution

The paper presents a novel hot pick-up technique for efficient, high-yield assembly of van der Waals heterostructures, including pre-patterned layers for complex architectures.

Findings

Near 100% yield in fabricating graphene stacks

Mean free paths up to 0.9 micrometers in monolayer devices

Transport affected by boundary scattering in narrow samples

Abstract

The assembly of individual two-dimensional materials into van der Waals heterostructures enables the construction of layered three-dimensional materials with desirable electronic and optical properties. A core problem in the fabrication of these structures is the formation of clean interfaces between the individual two-dimensional materials which would affect device performance. We present here a technique for the rapid batch fabrication of van der Waals heterostructures, demonstrated by the controlled production of 22 mono-, bi- and trilayer graphene stacks encapsulated in hexagonal boron nitride with close to 100% yield. For the monolayer devices we found semiclassical mean free paths up to 0.9 micrometer, with the narrowest samples showing clear indications of the transport being affected by boundary scattering. The presented method readily lends itself to fabrication of van der Waals heterostructures in both ambient and controlled atmospheres, while the ability to assemble pre-patterned layers paves the way for complex three-dimensional architectures.