H₂O on Graphene/Ir(111): A Periodic Array of Frozen Droplets

Abstract

Scanning tunneling microscopy (STM) and thermal desorption spectroscopy (TDS) show that deposition of water molecules onto epitaxial graphene on Ir(111) leads to the formation of an extended and well ordered array of amorphous water clusters. We trace the evolution of this cluster phase as dependent on water exposure and deposition temperature. The formation of separated clusters is due to binding energy differences within the moiré superstructure.