| AVS 61st International Symposium & Exhibition | |
| 2D Materials Focus Topic | Monday Sessions |
| Session 2D+AS+EM+NS+SS-MoA |
| Session: | Dopants, Defects, and Interfaces in 2D Materials |
| Presenter: | Jeremy Robinson, Naval Research Laboratory |
| Authors: | J. Robinson, Naval Research Laboratory M. Zalalutdinov, Naval Research Laboratory J. Culbertson, Naval Research Laboratory C. Junkermier, Naval Research Laboratory P.E. Sheehan, Naval Research Laboratory T. Reinecke, Naval Research Laboratory A. Friedman, Naval Research Laboratory |
| Correspondent: | Click to Email |
Graphene’s atomic thinness makes it highly sensitive to surface adsorbates or defects within its carbon backbone. Aside from the known effects and impact on electronic properties, here we demonstrate the impact of defects on the mechanical properties and the response of mechanical resonators. In particular, once defects are formed in atomically-thin materials they can be quite mobile and form more complicated defect structures such as bi- or tetra-vacancy clusters. We execute experiments using mechanical drum resonators made from single- to multi- to many-layer graphene systems. We use both CVD grown graphene and reduced graphene oxide (rGO) films to capture a wide range of defect structures. By measuring the fundamental frequency response of the resonators (in the MHz range) we extract properties such as tension, quality factor, and modulus as a function of external manipulation [1]. For highly defective rGO films measuring 10-40nm thick, we can tune the frequency response by 500% and quality factor by 20x through laser annealing, which effectively rearranges defects throughout the film [1]. Alternatively, using graphene 1-4 layers thick, we find the resonator response is significantly more sensitive to the formation and annihilation of meta-stable defects, such as the tetra-vacancy structure. We will show how the defect mobility and resonator response changes with different energy photons and come to understand these differences based on calculated defect migration energies of different defects types in graphene.
[1] Nano Letters12, 4212 (2012)