Electrochemical tuning of electronic states in single-wall carbon nanotubes studied byin situabsorption spectroscopy and ac resistance

2001 ◽  
Vol 78 (22) ◽  
pp. 3433-3435 ◽  
Author(s):  
S. Kazaoui ◽  
N. Minami ◽  
N. Matsuda ◽  
H. Kataura ◽  
Y. Achiba
Keyword(s):  
Carbon Nanotubes ◽  
Electronic States ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Electrochemical Tuning

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.

FET Properties of Surface Silylated Single Wall Carbon Nanotubes

2006 ◽  
Vol 963 ◽  
Author(s):  
Ryotaro Kumashiro ◽  
Nobuya Hiroshiba ◽  
Hirotaka Ohashi ◽  
Takeshi Akasaka ◽  
Yutaka Maeda ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Effect Transistors ◽  
Electronic States ◽  
Single Wall Carbon Nanotubes ◽  
Chemical Modifications ◽  
Single Wall Carbon ◽  
Chemically Modified ◽  
Carrier Doping ◽  
P Type ◽  
Spread Sheet

ABSTRACTSingle wall carbon nanotubes (SWNTs) having semiconducting properties are promising as electronic materials for nano-scale devices in the future, and the electrical properties of SWNTs are of significantly fundamental and practical interests. It is well known that the field effect transistors (FETs) fabricated using semiconducting SWNTs show high performance in terms of the mobility. However, carriers in pristine SWNTs are mostly holes and, therefore, SWNTs -FETs usually show p-type properties. As for SWNTs, chemical carrier doping has been reported so far for controlling carrier concentration like graphite intercalations. Two major techniques in SWNTs are generally possible; one is endohedral doping and the other is the exohedral chemical modifications. It has been exemplified that doping with alkali metals can introduce electron carriers into SWNTs. Furthermore, the electrical transport properties of SWNTs were reported to be controlled by the endohedral insertion of organic molecules inside the SWNTs. A similar carrier doping could exohedrally be possible when the SWNTs surface is chemically modified. With such chemical modifications, the charge transfer from the substituent groups to SWNTs will be expected and this could modify the electronic states of SWNTs. We reported the FET properties of individual SWNTs exohedrally modified by Si-containing organic moieties, and demonstrated that p-type nanotubes can be converted to n-type ones. However, because of ununiformity of the surface-chemical modifications of SWNTs, the true effects of the exohedral modifications on FET properties were extremely difficult to be evaluated. In this meeting, we will present comparison of the FET properties of the exohedrally silylated SWNTs between separated individual and spread-sheet samples. For evaluating the FET properties, the chemically modified SWNTs have been dispersed on a FET substrate, and the measurements have been carried out at ambient temperature using a conventional method for a separated SWNTs and a spread-sheet SWNTs film. As a reference, the experiments were also made in the same manner on chemically non-modified CNTs. From the experimental results, it will be demonstrated that an n-type property can be enhanced by the exohedral modifications both in the case of the spread-sheet samples and in the case of the individual ones. We will discuss the effects of surface silylation on the electronic states of these SWNTs.

scholarly journals Below-gap excitation of semiconducting single-wall carbon nanotubes

Nanoscale ◽  
2015 ◽  
Vol 7 (43) ◽  
pp. 18337-18342 ◽  
Author(s):  
G. Soavi ◽  
A. Grupp ◽  
A. Budweg ◽  
F. Scotognella ◽  
T. Hefner ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic States ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Unexpectedly, photons with energy well below the lowest exciton lead to linear excitation of electronic states in semiconducting swnts.

scholarly journals Localized and Delocalized Electronic States in Single-Wall Carbon Nanotubes

1998 ◽  
Vol 80 (21) ◽  
pp. 4729-4732 ◽  
Author(s):  
T. Pichler ◽  
M. Knupfer ◽  
M. S. Golden ◽  
J. Fink ◽  
A. Rinzler ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic States ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Effect of quantized electronic states on the dispersive Raman features in individual single-wall carbon nanotubes

2001 ◽  
Vol 65 (3) ◽  
Author(s):  
A. G. Souza Filho ◽  
A. Jorio ◽  
G. Dresselhaus ◽  
M. S. Dresselhaus ◽  
R. Saito ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic States ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon
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