scholarly journals Ion transport and electrochemical tuning of Fermi level in single-wall carbon nanotube probed by in situ Raman scattering

2006 ◽  
Vol 100 (8) ◽  
pp. 083711 ◽  
Author(s):  
S. Gupta ◽  
J. Robertson
Keyword(s):  
Carbon Nanotube ◽  
Raman Scattering ◽  
Ion Transport ◽  
Fermi Level ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
In Situ Raman ◽  
Electrochemical Tuning

In situ Raman spectro-electrochemistry study of single-wall carbon nanotube mat

2004 ◽  
Vol 13 (4-8) ◽  
pp. 1314-1321 ◽  
Author(s):  
S. Gupta ◽  
M. Hughes ◽  
A.H. Windle ◽  
J. Robertson
Keyword(s):  
Carbon Nanotube ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
In Situ Raman

Electrochemical Tuning of Single-Wall Carbon Nanotube Mat and Investigations on Actuator Mechanism

2004 ◽  
Vol 855 ◽  
Author(s):  
S. Gupta ◽  
M. Hughes ◽  
J. Robertson
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Bond Length ◽  
Upper Bound ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Electrochemical Tuning

ABSTRACTElectrochemical tuning of single-wall carbon nanotubes has been investigated using in situ Raman spectroscopy. We built a linear actuator from single-wall carbon nanotube mat and studied in several alkali metal (Li, Na, and K) and alkaline earth (Ca) halide solutions. The variation of bonding with electrochemical biasing was monitored using in situ Raman. This is since Raman can detect changes in C-C bond length: the radial breathing mode (RBM) at ∼190 cm−1 varies inversely with the nanotube diameter and the G band at ∼1590 cm−1 varies with the axial bond length. In addition, the intensities of both the modes vary significantly in a nonmonotonic manner pointing at the emptying/depleting or filling of the bonding and anti-bonding states - electrochemical charge injection. We discuss the variation of spectroscopic observables (intensity/frequency) of these modes providing valuable information on the charge transfer dynamics on the single-wall carbon nanotubes mat surface. We found the in-plane compressive strain (∼ -0.25%) and the charge transfer per carbon atom (fc ∼ -0.005) as an upper bound for the electrolytes used i.e. CaCl2. These results can be quantitatively understood in terms of the changes in the energy gaps between the one-dimensional van Hove singularities in the electron density of states arising possibly due to the alterations in the overlap integral of π bonds between the p orbitals of the adjacent carbon atoms. Moreover, the extent of variation of the absolute potential of the Fermi level or alternatively modification of band gap is estimated from modeling Raman intensity to be around 0.1 eV as an upper bound for CaCl2.

Raman Study of Single Wall Carbon Nanotube Doped by Alkali Metals

2000 ◽  
Vol 633 ◽  
Author(s):  
N. Bendiab ◽  
E. Anglaret ◽  
A. Righi ◽  
J.L. Sauvajol
Keyword(s):  
Carbon Nanotube ◽  
Raman Scattering ◽  
Alkali Metals ◽  
Low Frequency ◽  
The Other ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Alkali Atoms ◽  
Raman Study

AbstractSingle wall carbon nanotube (SWNT) doped by alkali-metals are investigated by Raman scattering. For saturation-doped compounds, the most striking intrinsic features are two low-frequency peaks assigned to modes involving both radial motions of tubes and alkali-atoms vibrations. On the other hand, the evolution of the Raman spectra with doping was studied in-situ. Two different stable phases are identified and associated to distinct organizations of the tubes and of the alkali-atoms.

Ion transport and electrochemical tuning of Fermi level in single-wall carbon nanotubes: In situ Raman scattering

2007 ◽  
Vol 22 (3) ◽  
pp. 603-614 ◽  
Author(s):  
S. Gupta
Keyword(s):  
Carbon Nanotubes ◽  
Raman Scattering ◽  
Fermi Level ◽  
Bond Length ◽  
Single Wall Carbon Nanotubes ◽  
Raman Intensity ◽  
Overlap Integral ◽  
Single Wall Carbon ◽  
In Situ Raman

The in situ Raman spectroscopy technique was used to investigate the ion transport and to determine the concomitant electrochemical tuning of Fermi level in single-wall carbon nanotubes. The variation of structural bonding in a single-wall carbon nanotube bundle dipped in aqueous alkaline earth halide electrolyte such as CaCl2 with electrochemical biasing was monitored. This is because Raman scattering can detect changes in C–C bond length through radial breathing mode (RBM) at ∼184 cm−1, which varies inversely with the nanotube diameter and the G band at ∼1590 cm−1, varying with the axial bond length. Consistent reversible and substantial variation in Raman intensity of both modes was induced by electrode potential point at the fine and continuous tuning (alternatively, emptying/depleting or filling) of the specific bonding and anti-bonding molecular states. Qualitatively, the results were explained in terms of changes in the energy gap occurring between the one-dimensional van Hove singularities present in the electron density of states, possibly arising due to the alterations in the overlap integral of π bonds between the p orbitals of the adjacent carbon atoms. We estimated the extent of variation of the absolute potential of the Fermi level and overlap integral (γ0) between the nearest-neighbor carbon atoms by modeling the electrochemical potential dependence of Raman intensity. Observations also suggested that the work function of the tube becomes larger for the metallic nanotubes in contrast to the simultaneously present semiconducting nanotubes.

Control of electron transport related defects in in situ fabricated single wall carbon nanotube devices

2006 ◽  
Vol 89 (13) ◽  
pp. 133124 ◽  
Author(s):  
Zhixian Zhou ◽  
R. Jin ◽  
Gyula Eres ◽  
Alaska Subedi ◽  
D. Mandrus
Keyword(s):  
Carbon Nanotube ◽  
Electron Transport ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Carbon Nanotube Devices

Correlation between in Situ Raman Scattering and Electrical Conductance for an Individual Double-Walled Carbon Nanotube

Nano Letters ◽  
2009 ◽  
Vol 9 (1) ◽  
pp. 383-387 ◽  
Author(s):  
Shaoning Yuan ◽  
Qing Zhang ◽  
Yumeng You ◽  
Ze-Xiang Shen ◽  
Daisuke Shimamoto ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Raman Scattering ◽  
Electrical Conductance ◽  
In Situ Raman

Raman scattering test of single-wall carbon nanotube composites

2001 ◽  
Vol 78 (21) ◽  
pp. 3193-3195 ◽  
Author(s):  
V. G. Hadjiev ◽  
M. N. Iliev ◽  
S. Arepalli ◽  
P. Nikolaev ◽  
B. S. Files
Keyword(s):  
Carbon Nanotube ◽  
Raman Scattering ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites
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