Formation and control of wrinkles in graphene by the wedging transfer method

TL;DR

This paper investigates how water drainage during wet transfer causes wrinkle formation in graphene, and demonstrates control over wrinkle orientation by modifying substrate surface properties, without compromising graphene's integrity.

Contribution

It reveals the role of water interaction in wrinkle formation and introduces a method to control wrinkle orientation through substrate surface morphology.

Findings

Wrinkles form due to water drainage during wet transfer.

Hydrophobic substrates prevent wrinkle formation.

Graphene's electrical and structural properties remain intact despite wrinkles.

Abstract

We study the formation of wrinkles in graphene upon wet transfer onto a target substrate, whereby draining of water appears to play an important role. We are able to control the orientation of the wrinkles by tuning the surface morphology. Wrinkles are absent in flakes transferred to strongly hydrophobic substrates, a further indication of the role of the interaction of water with the substrate in wrinkle formation. The electrical and structural integrity of the graphene is not affected by the wrinkles, as inferred from Raman measurements and electrical conductivity measurements.