Raman spectroscopy of diamond and doped diamond

Abstract

The optimization of diamond films as valuable engineering materials for a wide variety of applications has required the development of robust methods for their characterization. Of the many methods used, Raman microscopy is perhaps the most valuable because it provides readily distinguishable signatures of each of the different forms of carbon (e.g. diamond, graphite, buckyballs). In addition it is non-destructive, requires little or no specimen preparation, is performed in air and can produce spatially resolved maps of the different forms of carbon within a specimen. This article begins by reviewing the strengths (and some of the pitfalls) of the Raman technique for the analysis of diamond and diamond films and surveys some of the latest developments (for example, surface-enhanced Raman and ultraviolet Raman spectroscopy) which hold the promise of providing a more profound understanding of the outstanding properties of these materials. The remainder of the article is devoted to the uses of Raman spectroscopy in diamond science and technology. Topics covered include using Raman spectroscopy to assess stress, crystalline perfection, phase purity, crystallite size, point defects and doping in diamond and diamond films.

RETRACTED ARTICLE: Fundamental Discovery of New Phases and Direct Conversion of Carbon into Diamond and hBN into cBN and Properties

“…The Raman shift (Dx) is related to Dx (in cm À1 ) = 2.2 ± 0.10 cm À1 GPa À1 along the [111] direction, Dx (in cm À1 ) = 0.73 ± 0.20 cm À1 GPa À1 along the [100] direction, and Dx (in cm À1 ) = 3.2 ± 0.23 cm À1 GPa À1 for the hydrostatic component. [13] The biaxial stress in thin films can be described as a combination of two-thirds hydrostatic and one-third uniaxial stress. The biaxial stress can be estimated using r ¼ 2lðð1 þ mÞ=ð1 À mÞÞ:Da:DT, where l is shear modulus,m is Poisson's ratio, Da is the change in thermal coefficient of expansion and DT is the change in temperature.…”

“…This extension for BN phase diagram is very similar to the one proposed for carbon. [12,13] Similar to Q-carbon, we have created Q-BN, which is formed as a result of quenching from super undercooled state from which phase-pure cBN is grown in the form of single-crystal nanodots, microcrystals, nanoneedles, microneedles, and large-area films. We have also grown diamond on the top of these structures to create epitaxial cBN/diamond and diamond/cBN composites.…”

Raman scattering in boron-doped single-crystal diamond used to fabricate Schottky diode detectors

“…The frequency position, o, and the full width at half maximum, G, of the peaks are reported in Table 1. The asymmetric broadening and the downshift of the one-phonon Raman line of B-doped diamond observed both in polycrystalline and in homoepitaxial samples [14][15][16]19], have been explained as the result of a Fano-type discrete-continuum interaction between the discrete zone-centre phonon state and the continuum of the electronic states induced by the presence of the dopant [15,17,19,20]. Moreover, dopant incorporation at substitutional or interstitial sites can produce stress that generally depends on the doping level.…”

Directly observable G band splitting in Raman spectra from individual tubular graphite cones

“…Raman spectroscopy is one of the most powerful tools developed for the structural characterization of carbon based materials, such as diamond, carbon nanotube (CNT), fullerene, graphene and graphite etc [1][2][3][4][5][6][7][8]. In particular, it can distinguish the type (multiwall, metal or semiconducting single-wall) of CNTs based on the low-frequency radial breathing modes (RBMs) and the unique profile or line-shape of split G bands.…”