On the roughness of single- and bi-layer graphene membranes

TL;DR

This study investigates the surface roughness and spontaneous curvature of single- and bi-layer graphene membranes using transmission electron microscopy and diffraction techniques.

Contribution

It provides detailed visualization and analysis of the roughness and curvature in graphene membranes, highlighting differences between single and bi-layer structures.

Findings

Single-layer graphene membranes exhibit strong spontaneous curvature.

Two-layer membranes show measurable roughness through diffraction intensity variations.

The study offers direct visualization of membrane roughness and curvature.

Abstract

We present a detailed transmission electron microscopy and electron diffraction study of the thinnest possible membrane, a single layer of carbon atoms suspended in vacuum and attached only at its edges. Membranes consisting of two graphene layers are also reported. We find that the membranes exhibit an apparently random spontaneous curvature that is strongest in single-layer membranes. A direct visualization of the roughness is presented for two-layer membranes where we used the variation of diffracted intensities with the local orientation of the membrane.