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Monday, 29 April 2019

The substrate is alive! Scanning tunnelling miscroscopy to watch graphene growth on nickel surfaces

Dr Cristina Africh, from the Consiglio Nazionale delle Ricerche – Istituto Officina dei Materiali, presented on 24 April an ICN2 Seminar on the role of the substrate when generating graphene. Later that day she gave a talk in Casa Convalescència organised by the Istituto Italiano di Cultura in Barcelona with the support of the ICN2. This outreach event was organised in the context of the 500 anniversary of Leonardo da Vinci’s death.

Last Wednesday 24 the ICN2 hosted a seminar about the role of the substrate used in the process of graphene generation. The speaker was Dr Cristina Africh, from the Consiglio Nazionale delle Ricerche – Istituto Officina dei Materiali in Trieste (Italy). She is an expert in the dynamics of surface processes and explained to the audience her studies on the growth of graphene on nickel substrates.

The main tool to develop this research was a scanning tunnelling microscope (STM), which was used to record movies intended to analyse carefully the whole process of growth. To get better resolution they added a so-called “fast module” to the STM. It is worth noting that, in the framework of the Nanoscience Foundries and Fine Analysis - Europe project, she collaborated with Dr Jordi Fraxedas, Group Leader of the former ICN2 Force Probe Microscopy and Surface Nanoengineering Group. Through their collaboration they demonstrated that this fast module also works with atomic force microscopes (AFM).

One of the substantive results of her investigation is that there are nickel atoms that detach from the substrate and diffuse on the surface, getting trapped in the graphene’s edge. This nickel atom helps other carbon atoms to attach to the graphene flake which is being generated, thus facilitating the graphene growth process. She also explained how some impediments to the growth of graphene due to the substrate can be overcome by the substrate itself. For example, when the graphene flake encounters an irregularity such as a “cliff” in the substrate that prevents it from growing, some nickel atoms may form a kind of step that minimizes the unevenness of the surface, facilitating the growth of the graphene.

The scientific seminar was followed in the evening by an outreach event on graphene in the UAB’s Casa Convalescència, located in the Hospital de la Santa Creu i Sant Pau. This event was hosted by the Istituto Italiano di Cultura (IIC) in Barcelona with the support of the ICN2. The event, organised in the context of the 500 anniversary of Leonardo da Vinci’s death, was attended by Angelo Gioè, Director of the IIC, who read a letter from the President of Italy, Sergio Mattarella, and Gaia Lucilla Danese, Italian Consul General in Barcelona. The meeting was an opportunity to strengthen institutional ties within the Italian community.