Low-energy electron transmission imaging of clusters on free-standing graphene

TL;DR

This study demonstrates that free-standing graphene can be used as an effective transparent carrier for low-energy electron holography, enabling imaging of nanometer-sized objects with high clarity and revealing new effects like Moire patterns.

Contribution

The paper introduces the use of free-standing graphene as a transparent sample carrier for low-energy electron holography, including preparation methods and experimental validation.

Findings

Graphene exhibits 27% opacity per layer at 66 eV.

Holography can reveal shapes and distributions of nanometer objects.

Moire effects are observed in multi-layer graphene.

Abstract

We investigated the utility of free-standing graphene as a transparent sample carrier for imaging nanometer-sized objects by means of low-energy electron holography. The sample preparation for obtaining contamination-free graphene as well as the experimental setup and findings are discussed. For incoming electrons with 66 eV kinetic energy graphene exhibits 27% opacity per layer. Hence, electron holograms of nanometer-sized objects adsorbed on free-standing graphene can be recorded and numerically reconstructed to reveal the object's shapes and distribution. Furthermore, a Moire effect has been observed with free-standing graphene multi-layers.