Low-energy electron transmission imaging of clusters on free-standing 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 objects shapes and distribution. Furthermore, a Moiré effect has been observed with free-standing graphene multi-layers. © 2012 American Institute of Physics.