Amorphous Graphene-Based Plasmonic Metasurface for Near-Infrared Absorbers*

We experimentally demonstrated an amorphous graphene-based metasurface yielding near-infrared super absorber characteristics. The structure is obtained by alternatively combining magnetron-sputtering deposition and graphene transfer coating fabrication techniques. The thickness constraint of physical vapor deposited amorphous metallic layer is unlocked and as a result, the as-fabricated graphene-based metasurface absorber achieves near-perfect absorption in the near-infrared region with an ultra-broad spectral bandwidth of 3.0 μm. Our experimental characterization and theoretical analysis further points out that the strong light-matter interaction observed is caused by localized surface plasmon resonance of the metal film’s particle-like surface morphology. In addition to the enhanced light absorption characteristics, such an amorphous metasurface can be used for surface-enhanced Raman scattering applications. Meanwhile, the proposed graphene-based metasurface relies solely on CMOS-compatible, low cost and large-area processing, which can be flexibly scaled up for mass-production.