Graphene plasmonics
From Wikipedia, the free encyclopedia
Graphene is a 2D nanosheet with atomic thin thickness in terms of 0.34 nm. Due to the ultrathin thickness, graphene showed many properties that are quite different from their bulk graphite counterparts. The most prominent advantages are known to be their high electron mobility and high mechanical strengths. [1] [2][3] Thus, it exhibits potential for applications in optics and electronics especially for the development of wearable devices as flexible substrates. More importantly, the optical absorption rate of graphene is 2.3% in the visible and near-infrared region. This broadband absorption characteristic also attracted great attention of the research community to exploit the graphene-based photodetectors/modulators.[4][5][6]
Plasmons are collective electron oscillations usually excited at metal surfaces by a light source. Doped graphene layers have also shown the similar surface plasmon effects to that of metallic thin films.[7][8] Through the engineering of metallic substrates or nanoparticles (e.g., gold, silver and copper) with graphene, the plasmonic properties of the hybrid structures could be tuned for improving the optoelectronic device performances.[9][10] The electrons at the metallic structure could transfer to the graphene conduction band. This is attributed to the zero bandgap property of graphene nanosheet.
Graphene plasmons can also be decoupled from their environment and give rise to genuine Dirac plasmon at low-energy range where the wavelengths exceed the damping length. These graphene plasma resonances have been observed in the GHz–THz electronic domain.[11]
Graphene plasmonics is an emergent research field, that is attracting plenty of interest and has already resulted in a textbook.[12]
