Breakdown of Universal Scaling for Nanometer-Sized Bubbles in Graphene
Renán Villarreal, Pin-Cheng Lin, Fahim Faraji, Nasim Hassani, Harsh Bana, Zviadi Zarkua, Maya Narayanan Nair, Hung‐Chieh Tsai, Manuel Auge, Felix Junge, Hans Hofsaess, Stefan De Gendt, Steven De Feyter, Steven Brems, E. Harriet Åhlgren, Erik C. Neyts, Lucian Covaci, F. M. Peeters, M. Neek-Amal, L. M. C. Pereira
Abstract
We report the formation of nanobubbles on graphene with a radius of the order of 1 nm, using ultralow energy implantation of noble gas ions (He, Ne, Ar) into graphene grown on a Pt(111) surface. We show that the universal scaling of the aspect ratio, which has previously been established for larger bubbles, breaks down when the bubble radius approaches 1 nm, resulting in much larger aspect ratios. Moreover, we observe that the bubble stability and aspect ratio depend on the substrate onto which the graphene is grown (bubbles are stable for Pt but not for Cu) and trapped element. We interpret these dependencies in terms of the atomic compressibility of the noble gas as well as of the adhesion energies between graphene, the substrate, and trapped atoms.