Raman spectroscopy

About: Raman spectroscopy is a research topic. Over the lifetime, 122605 publications have been published within this topic receiving 2891083 citations. The topic is also known as: Raman Spectrum Analysis & spectrum Analysis, Raman.

Evolution of Graphene Growth on Ni and Cu by Carbon Isotope Labeling

Abstract: Large-area graphene growth is required for the development and production of electronic devices. Recently, chemical vapor deposition (CVD) of hydrocarbons has shown some promise in growing large-area graphene or few-layer graphene films on metal substrates such as Ni and Cu. It has been proposed that CVD growth of graphene on Ni occurs by a C segregation or precipitation process whereas graphene on Cu grows by a surface adsorption process. Here we used carbon isotope labeling in conjunction with Raman spectroscopic mapping to track carbon during the growth process. The data clearly show that at high temperatures sequentially introduced isotopic carbon diffuses into the Ni first, mixes, and then segregates and precipitates at the surface of Ni forming graphene and/or graphite with a uniform mixture of 12C and 13C as determined by the peak position of the Raman G-band peak. On the other hand, graphene growth on Cu is clearly by surface adsorption where the spatial distribution of 12C and 13C follows the pre...

3D Graphene–Cobalt Oxide Electrode for High-Performance Supercapacitor and Enzymeless Glucose Detection

Abstract: Using a simple hydrothermal procedure, cobalt oxide (Co3O4) nanowires were in situ synthesized on three-dimensional (3D) graphene foam grown by chemical vapor deposition. The structure and morphology of the resulting 3D graphene/Co3O4 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The 3D graphene/Co3O4 composite was used as the monolithic free-standing electrode for supercapacitor application and for enzymeless electrochemical detection of glucose. We demonstrate that it is capable of delivering high specific capacitance of ∼1100 F g–1 at a current density of 10 A g–1 with excellent cycling stability, and it can detect glucose with a ultrahigh sensitivity of 3.39 mA mM–1 cm–2 and a remarkable lower detection limit of <25 nM (S/N = 8.5).

Raman Spectroscopy of Carbon Materials: Structural Basis of Observed Spectra

Abstract: calculations of the phonon density of states, Al-Jishi and Dresselha~s~~~~~ have attributed the second-order bands

Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength

Abstract: Intense Raman scattering by pyridine molecules adsorbed on silver or gold aqueous sol particles of dimensions comparable to the wavelength is reported. The degree of intensity enhancement is strongly dependent on the excitation wavelength, with a sharp resonance Raman maximum for excitation at the wavelength of the Mie extinction maximum of the metal particles, and for the silver sols the Raman maximum is shown to follow the extinction maximum to longer wavelengths with increase in particle size. A new resonance Raman phenomenon is thus proposed which is the Raman component of resonant Mie scattering, and in which the polarizability of the metal particles is modulated by the vibrations of the adsorbed molecules. These observations confirm that surface plasma oscillations are involved in the intense Raman scattering already reported for molecules adsorbed at roughened silver surfaces. The metal dielectric function requirements for resonant Mie scattering enable the optimum excitation wavelength for plasma resonance-enhanced Raman studies at the surface of other metals to be estimated.