Graphene-Supported High-Resolution TEM and STEM Imaging of Silicon Nanocrystals and their Capping Ligands

Abstract

Using graphene as an ultrathin support, high-resolution transmission and scanning transmission electron microscopy (TEM and STEM) images of organic ligand-stabilized silicon (Si) nanocrystals with unprecedented clarity were obtained. TEM images of Si nanocrystals are usually obscured on conventional amorphous carbon TEM supports because of low atomic number (<i>Z</i>) contrast. The atomically thin graphene supports enabled clear images of the crystalline Si cores and, for the first time, organic capping ligands. Various twin defects were observed, often accompanied by very significant lattice distortion and anisotropic strain