Raman spectroscopy is here shown to provide a powerful tool to differentiate between two different sp2 carbon nanostructures (carbon nanotubes and graphene) which have many properties in common and others that differ. Emphasis is given to the richness of both carbon nanostructures as prototype examples of nanostructured materials. A glimpse toward future developments in this field is presented.

Perspectives on Carbon Nanotubes and Graphene Raman Spectroscopy

We show that the Raman scattering technique can give complete structural information for one-dimensional systems, such as carbon nanotubes. Resonant confocal micro-Raman spectroscopy of an (n,m) individual single-wall nanotube makes it possible to assign its chirality uniquely by measuring one radial breathing mode frequency omega(RBM) and using the theory of resonant transitions. A unique chirality assignment can be made for both metallic and semiconducting nanotubes of diameter d(t), using the parameters gamma(0) = 2.9 eV and omega(RBM) = 248/d(t). For example, the strong RBM intensity observed at 156 cm(-1) for 785 nm laser excitation is assigned to the (13,10) metallic chiral nanotube on a Si/SiO2 surface.

Structural (n,m) determination of isolated single wall carbon nanotubes by resonant Raman scattering

This paper reviews progress that has been made in the use of Raman spectroscopy to study graphene and carbon nanotubes These are two nanostructured forms of sp2 carbon materials that are of major current interest These nanostructured materials have attracted particular attention because of their simplicity, small physical size and the exciting new science they have introduced This review focuses on each of these materials systems individually and comparatively as prototype examples of nanostructured materials In particular, this paper discusses the power of Raman spectroscopy as a probe and a characterization tool for sp2 carbon materials, with particular emphasis given to the field of photophysics Some coverage is also given to the close relatives of these sp2 carbon materials, namely graphite, a three-dimensional (3D) material based on the AB stacking of individual graphene layers, and carbon nanoribbons, which are one-dimensional (1D) planar structures, where the width of the ribbon is on the nano

Raman spectroscopy of graphene and carbon nanotubes

Recent advances in Raman spectroscopy for characterizing graphene, graphite, and carbon nanotubes are reviewed comparatively We first discuss the first-order and the double-resonance (DR) second-order Raman scattering mechanisms in graphene, which give rise to the most prominent Raman features Then, we review phonon-softening phenomena in Raman spectra as a function of gate voltage, which is known as the Kohn anomaly Finally, we review exciton-specific phenomena in the resonance Raman spectra of single-wall carbon nanotubes (SWNTs) Raman spectroscopy of SWNTs has been especially useful for understanding many fundamental properties of all sp2 carbons, given SWNTs can be either semiconducting or metallic depending on their geometric structure, which is denoted by two integers (n,m)

Characterizing Graphene, Graphite, and Carbon Nanotubes by Raman Spectroscopy

Ultrasmooth, Large‐Area, High‐Uniformity, Conductive Transparent Single‐Walled‐Carbon‐Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

Resonance Raman scattering is used to determine the radial breathing mode (RBM) frequency $({\ensuremath{\omega}}_{\text{RBM}})$ dependence on tube diameter $({d}_{t})$ for single-wall carbon nanotubes (SWNTs). We establish experimentally the ${\ensuremath{\omega}}_{\text{RBM}}=227.0/{d}_{t}$ as the fundamental relation for pristine SWNTs. All the other RBM values found in the literature can be explained by an upshift in frequency due mostly to van der Waals interaction between SWNTs and environment.

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Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes

In the last decade, many theoretical and experimental achievements have been made in the photophysics of single wall carbon nanotubes (SWNTs). Such accomplishments allowed us to gain a deep understanding of the photophysics behind the transition energy (Eii) and the radial breathing mode frequency ( ω RBM ) dependence on nanotube chirality (n, m). This work is devoted to assemble and discuss what has been done on the research of the SWNT electronic and vibrational properties, based on the radial breathing mode (RBM) resonance Raman spectroscopy. Attention is directed to the understanding of how a change in the environment changes the correlation between ( E ii , ω RBM ) and (n, m). From the analysis of several data in the literature, we derive a simple routine for the ( E ii , ω RBM ) → ( n , m ) assignment.

Resonance Raman spectroscopy of the radial breathing modes in carbon nanotubes

We study a single-wall carbon nanotube (SWNT) sample grown by water-assisted chemical vapor deposition with both resonance Raman scattering (RRS) and high resolution transmission electron microscopy. High resolution transmission electron microscopy measurements of 395 SWNTs determined the diameter distribution of the sample, allowing us to calibrate an RRS radial breathing mode (RBM) map obtained with 51 laser excitation energies from 1.26 to 1.73 eV. Thus, we determined the diameter dependence of the RRS RBM cross-section, which in turn allows the determination of the diameter distribution of any SWNT sample by measuring the RBM Raman signal.

Calibrating the single-wall carbon nanotube resonance Raman intensity by high resolution transmission electron microscopy for a spectroscopy-based diameter distribution determination

Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes. Phys Rev B 77:241403

The accurate and reproducible measurement of the properties and performance characteristics of nanoscale materials, devices and systems are essential for quality and process control, commercial transactions and effective regulations. Scientists, manufacturers, governments, regulators and health and environmental protection agencies, will need measurement systems and evaluation protocols supported by well founded and robust standards, both physical and documentary. In this paper we discuss some fundamental aspects of the use of the resonance Raman spectroscopy of the radial breathing mode (RBM) of single wall carbon nanotubes (SWNTs) for metrological purposes. The achievements and problems are pointed, hoping for the development of procedures capable of making the promised nanotechnology revolution to become a reality.

P. B. C. Pesce

Papers

Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes

Resonance Raman spectroscopy of the radial breathing modes in carbon nanotubes

Calibrating the single-wall carbon nanotube resonance Raman intensity by high resolution transmission electron microscopy for a spectroscopy-based diameter distribution determination

Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes. Phys Rev B 77:241403

The fundamental aspects of carbon nanotube metrology