All-Dry Transfer of Graphene Film by Van der Waals Interactions

TL;DR

This paper introduces a dry transfer method for high-quality graphene films using van der Waals interactions, enabling clean, uniform transfers from Ge(110) substrates to other surfaces.

Contribution

The study demonstrates a novel dry transfer technique leveraging weak van der Waals forces, achieving high-quality graphene transfer with minimal defects and strain.

Findings

Transferred graphene films are uniform and low in defects.

The interfacial adhesion energy between graphene and Ge(110) is below typical van der Waals energies.

Graphene on Ge(110) can be integrated with other materials via clean assembly.

Abstract

We report a method that uses van der Waals interactions to transfer continuous, high-quality graphene films from Ge(110) to a different substrate held by hexagonal boron nitride carriers in a clean, dry environment. The transferred films are uniform and continuous with low defect density and few charge puddles. The transfer is effective because of the weak interfacial adhesion energy between graphene and Ge. Based on the minimum strain energy required for the isolation of film, the upper limit of the interfacial adhesion energy is estimated to be 23 meV per carbon atom, which makes graphene/Ge(110) the first as-grown graphene film that has an substrate adhesion energy lower than typical van der Waals interactions between layered materials. Our results suggest that graphene on Ge can serve as an ideal material platform to be integrated with other material systems by a clean assembly process.