Charge transport in surfactant‐free single walled carbon nanotube networks

Ravi, Shrividya; Kaiser, A. B.; Bumby, Chris W.

doi:10.1002/pssb.201300033

Cited by 17 publications

(19 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 a). A similar phenomenon was measured in non-separated Buckypapers 45 – 47 , where the high-temperature factor was interpreted as a characteristic phonon scattering in 1D conductor 11 , 12 or as a result of the concentric expansion of the tubes (radial breathing), which constantly change the distance between tubes and reduce the tunneling probability 41 , 48 . This effect could be also related with the de-doping effect 26 , 37 , but in our case we excluded this by proper annealing before measurement (see Fig.…”

Section: Resultssupporting

confidence: 60%

Determination of the electronic transport in type separated carbon nanotubes thin films doped with gold nanocrystals

Świniarski

Dużyńska

Gertych

et al. 2021

Sci Rep

View full text Add to dashboard Cite

We report a systematic theoretical and experimental investigation on the electronic transport evolution in metallic and semiconducting carbon nanotubes thin films enriched by gold nanocrystals. We used an ultra-clean production method of both types of single-walled carbon nanotube thin films with/without gold nanocrystals, which were uniformly dispersed in the whole volume of the thin films, causing a modification of the doping level of the films (verified by Raman spectroscopy). We propose a modification of the electronic transport model with the additional high-temperature features that allow us to interpret the transport within a broader temperature range and that are related to the conductivity type of carbon nanotubes. Moreover, we demonstrate, that the proposed model is also working for thin films with the addition of gold nanocrystals, and only a change of the conductivity level of our samples is observed caused by modification of potential barriers between carbon nanotubes. We also find unusual behavior of doped metallic carbon nanotube thin film, which lowers its conductivity due to doping.

show abstract

Section: Resultssupporting

confidence: 60%

Determination of the electronic transport in type separated carbon nanotubes thin films doped with gold nanocrystals

Świniarski

Dużyńska

Gertych

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Among several interesting points to note, we highlight that the parameter G a has negative values. Ravi et al followed the same analysis to explain the temperature-dependent conductance variation for carbon-nanotube networks by including a thermal activation term. , Although the fitting parameters were not available, they assumed three types of parallel conducting pathways along which the dominant conducting mechanisms are VRH, quantum tunneling, and thermal activation. However, we argue that the negative values of G a imply that the medium disordered regions giving the thermal activation term in eq do not form their own separate conducting pathways but are embedded as a constituent in the VRH and/or quantum tunneling pathways.…”

Section: Resultsmentioning

confidence: 99%

Charge Transport in Thick Reduced Graphene Oxide Film

Kim

Jung

et al. 2015

J. Phys. Chem. C

View full text Add to dashboard Cite

We have investigated temperature-dependent charge transport behavior in thick reduced graphene oxide (RGO) film. Our results show that charges transport through two parallel percolating conducting pathways. One contains large disordered regions as one of its constituents, so its conductance is determined dominantly by variable range hopping (VRH). The other is composed of small and medium disordered regions and crystalline sp2 domains, so its conductance is determined by a serial connection of quantum tunneling and thermal activation. The more oxygen functional groups are removed from GO film upon progressive reduction, the lower the potential barriers between the crystalline sp2 domains and disordered regions become. The contribution of thermal activation to total conductance does not appear evidently for highly reduced GO film having low potential barriers, but thermal activation causes the conductance of moderately reduced film to change continuously, even at low temperatures where the VRH is almost frozen out.

show abstract

“…The availability of Fermi level electronic states can be justified when the SWNT network is formed from a mixture of MT-and SC-SWNTs, only MT-SWNTs, or heavily doped SC-SWNTs, which are capable of providing a finite density of states in the vicinity of the Fermi level. [27][28][29][30]32 In the next two sections, the contributions of residual concentration of MT-SWNTs to the conductance of a predominantly SC-SWNT network and the effect of the doping of SC-SWNTs will be analyzed in order to delineate the nature of the Fermi level electronic states contributing to the weak temperature dependence of conductivity of SC-SWNT networks.…”

Section: Columns 2 and 3 Inmentioning

confidence: 99%

“…The inverse temperature plot (Figure 2d) shows that the low temperature region is associated with very low energy processes of a variable activation energy, E LT = 2−10 meV, similar in magnitude to the weak temperature dependences reported in literature for networks of mixed MT-and SC-SWNTs. [27][28][29][30]32 We tested several models that were reported to describe the electrical transport in SWNT networks. 27−32 Figure 3 presents a fitting of the experimental data using fluctuation induced tunneling (FIT) model, 33,34 2D variable range hopping model (2D-VRH), 35 and Efros and Shklovskii VRH model, denoted as ES-VRH, which takes into account Coulomb interactions.…”

Section: Temperature Dependence Of Conductivitymentioning

confidence: 99%

Networks of Semiconducting SWNTs: Contribution of Midgap Electronic States to the Electrical Transport

et al. 2015

View full text Add to dashboard Cite

Single-walled carbon nanotube (SWNT) thin films provide a unique platform for the development of electronic and photonic devices because they combine the advantages of the outstanding physical properties of individual SWNTs with the capabilities of large area thin film manufacturing and patterning technologies. Flexible SWNT thin film based field-effect transistors, sensors, detectors, photovoltaic cells, and light emitting diodes have been already demonstrated, and SWNT thin film transparent, conductive coatings for large area displays and smart windows are under development. While chirally pure SWNTs are not yet commercially available, the marketing of semiconducting (SC) and metallic (MT) SWNTs has facilitated progress toward applications by making available materials of consistent electronic structure. Nevertheless the electrical transport properties of networks of separated SWNTs are inferior to those of individual SWNTs. In particular, for semiconducting SWNTs, which are the subject of this Account, the electrical transport drastically differs from the behavior of traditional semiconductors: for example, the bandgap of germanium (E = 0.66 eV) roughly matches that of individual SC-SWNTs of diameter 1.5 nm, but in the range 300-100 K, the intrinsic carrier concentration in Ge decreases by more than 10 orders of magnitude while the conductivity of a typical SC-SWNT network decreases by less than a factor of 4. Clearly this weak modulation of the conductivity hinders the application of SC-SWNT films as field effect transistors and photodetectors, and it is the purpose of this Account to analyze the mechanism of the electrical transport leading to the unusually weak temperature dependence of the electrical conductivity of such networks. Extrinsic factors such as the contribution of residual amounts of MT-SWNTs arising from incomplete separation and doping of SWNTs are evaluated. However, the observed temperature dependence of the conductivity indicates the presence of midgap electronic states in the semiconducting SWNTs, which provide a source of low-energy excitations, which can contribute to hopping conductance along the nanotubes following fluctuation induced tunneling across the internanotube junctions, which together dominate the low temperature transport and limit the resistivity of the films. At high temperatures, the intrinsic carriers thermally activated across the bandgap as in a traditional semiconductor became available for band transport. The midgap states pin the Fermi level to the middle of the bandgap, and their origin is ascribed to defects in the SWNT walls. The presence of such midgap states has been reported in connection with scanning tunneling spectroscopy experiments, Coulomb blockade observations in low temperature electrical measurements, selective electrochemical deposition imaging, tip-enhanced Raman spectroscopy, high resolution photocurrent spectroscopy, and the modeling of the electronic density of states associated with various defects. Midgap states are present in conventional sem...

show abstract

Charge transport in surfactant‐free single walled carbon nanotube networks

Cited by 17 publications

References 21 publications

Determination of the electronic transport in type separated carbon nanotubes thin films doped with gold nanocrystals

Determination of the electronic transport in type separated carbon nanotubes thin films doped with gold nanocrystals

Charge Transport in Thick Reduced Graphene Oxide Film

Networks of Semiconducting SWNTs: Contribution of Midgap Electronic States to the Electrical Transport

Contact Info

Product

Resources

About