Sign inversion in the terahertz photoconductivity of single-walled carbon nanotube films
arXiv:1804.11113 · doi:10.1103/PhysRevB.98.241404
Abstract
In recent years, there have been conflicting reports regarding the ultrafast photoconductive response of films of single walled carbon nanotubes (CNTs), which apparently exhibit photoconductivities that can differ even in sign. Here, we observe explicitly that the THz photoconductivity of CNT films is a highly variable quantity which correlates with the length of the CNTs, while the chirality distribution has little influence. Moreover, by comparing the photo-induced change in THz conductivity with heat-induced changes, we show that both occur primarily due to heat-generated modification of the Drude electron relaxation rate, resulting in a broadening of the plasmonic resonance present in finite-length metallic and doped semiconducting CNTs. This clarifies the nature of the photo-response of CNT films and demonstrates the need to carefully consider the geometry of the CNTs, specifically the length, when considering them for application in optoelectronic devices.
arXiv commentSubmitted to Physical Review Letters: Currently being reviewed by referees. Main manuscript: 5 pages, 3 figures. Supplementary data: 6 pages, 6 figures
References in corpus (7)
- Band Structure, Phonon Scattering and the Ultimate Performance of Single-Walled Carbon Nanotube Transistors
- Collective modes of the massless Dirac plasma
- Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes
- Study of charge dynamics in transparent single-walled carbon nanotube films
- Ultrafast terahertz probes of interacting dark excitons in chirality-specific semiconducting single-walled carbon nanotubes
- Coherent plasmon and phonon-plasmon resonances in carbon nanotubes
- Influence of nanotube length and density on the plasmonic terahertz response of single-walled carbon nanotubes