scholarly journals Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Yasumitsu Miyata ◽  
Kohei Mizuno ◽  
Hiromichi Kataura
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Defect Density ◽  
Arc Discharge ◽  
Chemical Vapor ◽  
Synthetic Methods ◽  
Single Wall Carbon Nanotubes ◽  
Sem Images ◽  
Single Wall Carbon ◽  
Swcnt Sample

We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs) produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio) reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

In Situ Atomic Force Microscopy Tip-Induced Deformations and Raman Spectroscopy Characterization of Single-Wall Carbon Nanotubes

Nano Letters ◽  
2012 ◽  
Vol 12 (8) ◽  
pp. 4110-4116 ◽  
Author(s):  
P. T. Araujo ◽  
N. M. Barbosa Neto ◽  
H. Chacham ◽  
S. S. Carara ◽  
J. S. Soares ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Force Microscopy ◽  
Atomic Force

Enhanced yield strength in iron nanocomposite with in situ grown single-wall carbon nanotubes

2006 ◽  
Vol 21 (2) ◽  
pp. 522-528 ◽  
Author(s):  
A. Goyal ◽  
D.A. Wiegand ◽  
F.J. Owens ◽  
Z. Iqbal
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Yield Strength ◽  
Vapor Deposition ◽  
Single Wall Carbon Nanotubes ◽  
Iron Matrix ◽  
Single Wall Carbon ◽  
X Ray ◽  
Micro Raman Spectroscopy

The yield strength of iron-carbon nanotube composites fabricated by in situ chemical vapor deposition of 2.2 vol% single-wall carbon nanotubes (SWNTs) inside an iron matrix showed substantial enhancement up to 45%, relative to that of similarly treated pure iron samples without carbon nanotubes of the same piece density. The work hardening coefficient and the Vickers hardness coefficient also significantly increased in these composites relative to the reference samples. X-ray diffraction together with energy dispersive x-ray measurements and micro-Raman spectroscopy indicated no concomitant formation of carbides and very little amorphous carbon during the vapor deposition process. Micro-Raman spectroscopy and scanning and transmission electron microscopy showed spectral signatures and images, respectively, indicating the formation and dispersion of SWNTs within the cavities of the iron matrix. It is suggested that the increased strength of the nanocomposites was due to the mechanical support provided to these cavities by the extremely strong SWNTs.

Charge Transfer Dynamics in Single-Wall Carbon Nanotubes Mat: In Situ Raman Spectroscopy

2003 ◽  
Vol 785 ◽  
Author(s):  
S. Gupta ◽  
M. Hughes ◽  
A.H. Windle ◽  
J. Robertson
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Charge Transfer ◽  
Bond Length ◽  
Mechanical Response ◽  
Radial Breathing Mode ◽  
Single Wall Carbon Nanotubes ◽  
In Situ Raman Spectroscopy ◽  
Single Wall Carbon

ABSTRACTCarbon nanotubes-based actuator has been investigated using in situ Raman spectroscopy in order to understand the actuation mechanism and to determine associated parameters. We built an actuator from a sheet of single-wall carbon nanotubes (SWNT mat) and studied in several alkali metal (Li, Na, and K) and alkaline earth (Ca) halide solutions. 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, the variation of bonding was monitored with potential. In addition, the intensities of both the modes vary with either emptying/depleting or filling of the bonding and antibonding states due to electrochemical charge injection. We discuss the variation of intensity/frequency providing valuable information on the dynamics of charge transfer on the SWNT mat surface. We found the in-plane microscopic strain (∼ -0.25%) and the charge transfer per carbon atom (fc ∼ -0.005) as an upper bound for the electrolytes used. It is demonstrated that though the present analyses does comply with the proposition made earlier, but the quantitative estimates of the associated parameters are significantly lower if compared with those of reported values for carbon nanotubes. Moreover, the extent of variation (i.e. coupled electro-chemo-mechanical response) does depend upon the type of counter-ion used. The cyclic voltammetry (CV) is also described briefly.

Electrical Resistance of Single-Wall Carbon Nanotubes with Determined Chiral Indices

2009 ◽  
Vol 1204 ◽  
Author(s):  
Letian Lin ◽  
Lu-Chang Qin ◽  
Sean Washburn ◽  
Scott Paulson
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Vapor Deposition ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Transmission Electron ◽  
Highly Sensitive

AbstractThe properties of a carbon nanotube (CNT), in particular a single-wall carbon nanotube (SWNT), are highly sensitive to the atomic structure of the nanotube described by its chirality (chiral indices). We have grown isolated SWNTs on a silicon substrate using chemical vapor deposition (CVD) and patterned sub-micron probes using electron beam lithography. The SWNT was exposed by etching the underlying substrate for transmission electron microscope (TEM) imaging and diffraction studies. For each individual SWNT, its electrical resistance was measured by the four-probe method at room temperature and the chiral indices of the same SWNT were determined by nano-beam electron diffraction. The contact resistances were reduced by annealing to typically 3-5 kΩ. We have measured the I-V curve and determined the chiral indices of each nanotube individually from four SWNTs selected randomly – two are metallic and two are semiconducting. We will present the electrical resistances in correlation with the carbon nanotube diameter as well as the band gap calculated from the determined chiral indices for the semiconducting carbon nanotubes. These experimental results are also discussed in connection with theoretical estimations.

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