[21a-S011-1~12] 17.2 Graphene

[21a-S011-3] Dissociative ion scattering as a probe for elasticity of graphene

〇Kouzou Mochiji¹, Norio Inui¹, Kousuke Moritani¹ (1.University of Hyogo)

Keywords:cluster ion,dissociative ion scattering,probe for elasticity of graphene

We demonstrate a method to probe a graphene layer on copper by using cluster ions consisting of thousands of argon (Ar) atoms. Ar cluster ions colliding with a solid at kinetic energies below 5 eV/atom dissociate into smaller cluster ions such as Ar₂⁺ or Ar₃⁺, and the dissociation degree (ease of dissociation) depends on the elastic property such as Young’s modulus of the solid. We apply this phenomenon to probe a graphene layer on copper. Contaminants at the graphene surface are removed without damage to the surface by Ar cluster ion bombardment and the cleanliness of the surface is simultaneously probed by measuring the dissociation degree. This degree gradually approaches the value for a clean surface. After cleaning, the dissociation degree for pristine graphene on copper is five times lower than that for bare copper, indicating that the graphene layer acts as a buffer against the impact force of the cluster ion upon the collision. Accordingly, the method can probe the quality of graphene, such as carbon coverage, by comparing the dissociation degree with that for bare copper. Furthermore, the method can probe the interface between graphene and copper, showing that the dissociation degree increases with increasing copper oxidation. The obtained experimental results are compared with simulated results obtained by molecular dynamics simulation for the collisions of an Ar cluster ion with graphene on copper. The combined results are discussed with respect to the utility of the proposed method for controlling the quality of graphene in the manufacture of electronic or mechanical devices.