Dielectric\nConstant Engineering of Single-Walled Carbon\nNanotube Films for Metamaterials and Plasmonic Devices

Abstract

We demonstrate the fabrication of\nplasmonic and metamaterials devices,\noperating in the terahertz frequency range, by using highly conductive,\nsingle-walled carbon nanotube (SWNT) network films. We fabricated\nvarious patterns on the SWNT films using photolithography or laser\nmachining techniques, whose resonance behaviors are determined by\ngeometric parameters such as the periodicity of the array patterns\nor the shape of the individual elements. The excellent mechanical\nproperties of SWNT films enabled us to fabricate free-standing and\nhighly flexible devices. More importantly, using postprocessings such\nas chemical treatments and nanoparticle coatings, we were able to\nengineer the dielectric constants of the SWNT films, such as enhancing\nor degrading the conductive properties. As a result of the postprocessings,\nthe resonance peak of the plasmonic devices was suppressed or retrieved,\nwhich is not achievable in conventional metal films. In particular,\nwe were able to control the metamaterials resonances, implying the\npossibility of fabricating tunable optoelectronic devices without\nchanging the device structures.