Determining the Chiral Index of Semiconducting Carbon Nanotubes Using Photoconductivity Resonances

Abstract

We utilize photoconductivity spectroscopy to identify the unique chiral structure of individual carbon nanotubes (CNTs). Peaks in photoconductivity are measured throughout the visible and near-IR wavelength ranges. Photoconductivity peaks associated with individual CNTs are referenced against existing Rayleigh scattering measurements to uniquely identify chiral indices. We find close agreement between our assigned exciton resonances and the previously published exciton resonances. The typical net energy mismatch is ≤20 meV. By enabling chiral identification of CNTs after the completion of device fabrication, the technique offers a facile method for investigating relationships between CNT structure and electronic/optoelectronic properties.

Redefined Zagreb indices of Some Nano Structures

“…There have been many advances in Wiener index, Szeged index, PI index, and other degree-based or distance-based indices of molecular graphs, while the study of the redefined Zagreb indices of nano structures has been largely limited. Furthermore, nanotube, nanostar, polyomino chain and benzenoid series are critical and widespread molecular structures which have been widely applied in medical science, chemical engineering and pharmaceutical fields (see Mirzargar [18], Ashrafi and Karbasioun [1], Manuel et al, [16], Baca et al, [4], DeBorde et al, [5], Matsuno et al, [17], Vilela et al, [22], Velichko, Nosich [21], Haslam and Raeymaekers [12], Ashrafi and Karbasioun [2]). Also, these structures are the basic and primal structures of other more complicated chemical molecular structures and nano materials.…”

Optical visualization and polarized light absorption of the single-wall carbon nanotube to verify intrinsic thermal applications

“…Considering that the surrounding environment of CNTs (particularly the substrate and adjacent tubes 10,11 ) may remarkably affect the properties of CNTs, a reliable experimental determination of the intrinsic properties at the single-tube level is currently a matter of concern. Recent light absorption investigations of individual nanotubes have focused on different resonant and nonresonant modes using spatial modulation spectroscopy 12 , polarization-based homodyne microscope 13 , and photoconductivity spectra 14 . However, to avoid the optical detection difficulty from the small cross section of SWCNTs, the light-induced thermal effect was considered a suitable method to study the thermal and optical properties of CNTs, which is also significant to both the function of optical devices 15 and SWCNT species control [16][17][18] .…”

Cold exciton electroluminescence from air-suspended carbon nanotube split-gate devices

“…4 Further investigation of split-gate devices, in particular those utilizing air-suspended tubes, have revealed ideal diode behavior and superior photoconductivity performance. [17][18][19][20][21][22] Considering these experimental efforts on electrostatically formed pn-junctions in air-suspended CNTs, improved EL performance is expected as well.…”