  Electron-beam (e-beam) manipulation of single dopant atoms in an
aberration-corrected scanning transmission electron microscope is emerging as a
method for directed atomic motion and atom-by-atom assembly. Until now, the
dopant species have been limited to atoms closely matched to carbon in terms of
ionic radius and capable of strong covalent bonding with carbon atoms in the
graphene lattice. In situ dopant insertion into a graphene lattice has thus far
been demonstrated only for Si, which is ubiquitously present as a contaminant
in this material. Here, we achieve in situ manipulation of Pt atoms and their
insertion into the graphene host matrix using the e-beam deposited Pt on
graphene as a host system. We further demonstrate a mechanism for stabilization
of the Pt atom, enabled through the formation of Si-stabilized Pt heteroatomic
clusters attached to the graphene surface. This study provides evidence toward
the universality of the e-beam assembly approach, opening a pathway for
exploring cluster chemistry through direct assembly.
