Flattening van der Waals heterostructure interfaces by local thermal treatment

TL;DR

This paper introduces a laser-based local thermal treatment method to effectively remove bubbles at 2D material interfaces, improving heterostructure quality for electronic and optical applications.

Contribution

It presents a novel laser raster scanning technique to controllably flatten van der Waals heterostructure interfaces by removing bubbles, enhancing fabrication control.

Findings

Bubble density can be reduced using laser thermal treatment.

The flattening mechanism involves interface thermal conductivities and adhesion energies.

The method improves heterostructure interface quality.

Abstract

Fabrication of custom-built heterostructures based on stacked 2D materials provides an effective method to controllably tune electronic and optical properties. To that end, optimizing fabrication techniques for building these heterostructures is imperative. A common challenge in layer-by-layer assembly of 2D materials is the formation of bubbles at the atomically thin interfaces. We propose a technique for addressing this issue by removing the bubbles formed at the heterostructure interface in a custom-defined area using the heat generated by a laser, equipped with raster scanning capabilities. We demonstrate that the density of bubbles formed at graphene-ReS2 interfaces can be controllably reduced using this method. We discuss an understanding of the flattening mechanism by considering the interplay of interface thermal conductivities and adhesion energies between two atomically thin 2D materials.