Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes

• Published in: Nano letters 2013-12, Vol.13 (12), p.5991-5996
• Main Authors: Zhang, Qi, Hároz, Erik H, Jin, Zehua, Ren, Lei, Wang, Xuan, Arvidson, Rolf S, Lüttge, Andreas, Kono, Junichiro
• Format: Article
• Language: English
• Subjects: Absorption; Carbon nanotubes; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Direct current; Electric Conductivity; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotubes; Nanotubes, Carbon - chemistry; Physics; Plasmonics; Plasmons; Semiconductors; Single wall carbon nanotubes; Surface and interface electron states; Surface Plasmon Resonance; Terahertz frequencies; Transport
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl403175g

Plasmon resonance is expected to occur in metallic and doped semiconducting carbon nanotubes in the terahertz frequency range, but its convincing identification has so far been elusive. The origin of the terahertz conductivity peak commonly observed for carbon nanotube ensembles remains controversial. Here we present results of optical, terahertz, and direct current (DC) transport measurements on highly enriched metallic and semiconducting nanotube films. A broad and strong terahertz conductivity peak appears in both types of films, whose behaviors are consistent with the plasmon resonance explanation, firmly ruling out other alternative explanations such as absorption due to curvature-induced gaps.