Low-energy electron transmission imaging of clusters on free-standing   graphene
  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. 
Jean-Nicolas Longchamp, Tatiana Latychevskaia, Conrad Escher,   Hans-Werner Fink
cond-mat.mes-hall