Nanowriting with Clusters on Graphene on Ru(0001)

In this work, small clusters composed of approximately 67 iridium atoms have been grown on top of graphene on Ru(0001) surfaces. In a similar way to other materials grown on graphene on Ir(111) or Ru(0001) surfaces, these clusters form a monodisperse well-ordered array with a periodicity corresponding to the moire pattern of the graphene-metal system, i.e., approximately 3 nm. We have studied by in situ ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) the cluster adsorption sites as well as the height distributions. Moreover, we have used the ability of STM to manipulate the matter at the atomic scale and have extracted single clusters by gentle tip-sample approaches. The probability of single cluster extraction has been investigated as a function of the tip-sample approach. According to our experimental measurements, this probability is above 90% for approaches of 0.6 nm or beyond. We prove this reproducibility by nanowriting patterns which are stable for long periods of time at room temperature.