Real and apparent grain sizes in chemical vapor deposited diamond

Charles, SJ; Steeds, John W; Evans, Djf; Butler, James E.

doi:10.1016/s0167-577x(03)00152-6

Cited by 14 publications

(13 citation statements)

References 14 publications

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supporting

confidence: 91%

“…1 we show the large-scale STM and SEM (see the inset) images of borondoped diamond films, whose surface structure was the main target of this work. On both images one can easily see large diamond grains whose sizes range from 0.2 to 1:0 m, in close agreement with earlier published structural studies [26,27].At the next stage of experiments, the STM tip was positioned on top of the individual diamond microcrystal. The flat facets of diamond microcrystals that were selected for our measurements exhibited modest tilt, which was typically 30 and could be electronically compensated during STM data acquisition.…”

supporting

confidence: 87%

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Magic-Sized Diamond Nanocrystals

Altfeder

Voevodin

et al. 2009

Phys. Rev. Lett.

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The 2D structural transformation of a heavily boron-doped diamond surface has been revealed using scanning tunneling microscopy (STM). We found that at boron densities above the metal-insulator transition the diamond surface is comprised of spatially ordered magic-sized nanocrystals. The development of quantized electron gas inside these nanocrystals is directly confirmed by STM observation of standing electron waves. The experimental comparison of metallic and insulating diamond reveals the existence of the Fermi-sea-induced quantum selection rules for the self-assembly of nanostructures.

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supporting

confidence: 91%

supporting

confidence: 87%

Magic-Sized Diamond Nanocrystals

Altfeder

Voevodin

et al. 2009

Phys. Rev. Lett.

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“…Confocal micro-Raman imaging was also used by our group to investigate the structural and, to some extent, chemical inhomogeneities that exist in a high-quality, free-standing, polished, optically transparent boron-doped CVD diamond disk . Steeds et al used transmission electron microcopy (TEM) as well as photoluminescence and micro-SIMS to investigate the nature of the inhomogeneities on boron-doped CVD diamond films. − TEM showed that grains in thick polycrystalline CVD diamond form clusters with a common growth direction. The individual grains within a cluster are related by various twinning operations, which are characteristic of columnar CVD growth and do not depend on boron doping.…”

Section: Introductionmentioning

confidence: 99%

“…31 Steeds et al used transmission electron microcopy (TEM) as well as photoluminescence and micro-SIMS to investigate the nature of the inhomogeneities on boron-doped CVD diamond films. [32][33][34] TEM showed that grains in thick polycrystalline CVD diamond form clusters with a common growth direction. The individual grains within a cluster are related by various twinning operations, which are characteristic of columnar CVD growth and do not depend on boron doping.…”

Section: Introductionmentioning

confidence: 99%

Raman Imaging and Kelvin Probe Microscopy for the Examination of the Heterogeneity of Doping in Polycrystalline Boron-Doped Diamond Electrodes

et al. 2006

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The issue of the heterogeneity of boron doping in microcrystalline diamond films was addressed by four different methods: micro-Raman spectroscopy and Raman imaging, Kelvin probe force microscopy, conducting atomic force microscopy, and scanning electrochemical microscopy. The samples were commercially available films from Windsor Scientific, with an average boron concentration of about 5 x 10(20) cm(-3). In agreement with previous works, all of the methods showed that the boron uptake was nonuniform across the surface of the electrode. Two different types of regions were evidenced, with metallic or semiconducting properties that were characterized with different types of Raman spectra. The line shape of these spectra was strongly dependent on the excitation wavelength. Local variations in electroactivity were evidenced by the SECM curves, which are related to the electronic properties of the individual grains, which, in turn, are governed by the boron content of the individual crystallites. In this study, two different micro-Raman imaging techniques were used that reveal the grain structure of the films: the images constructed from the diamond line intensity perfectly reproduced the optical image obtained by illuminating the sample in reflection. The method also allows detection of the presence of nondiamond carbon, especially in the metallic parts of the samples. Other spectral features (intensity of the boron-related broad lines, as well as the frequency and width of the diamond line) were used to construct images. In every case, the grain structure of the film was revealed, as well as twinning within individual crystallites. All approaches revealed that no enhanced doping or boron depletion occurred at the grain boundaries.

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“…As a result, it is difficult to estimate the grain size within the particulates. In any event, TEM [17] has revealed the presence of extensive twinning and other defects in CVD diamond films. Similar defects within particulate diamond grown by the current methods would be anticipated.…”

Section: ±1mentioning

confidence: 99%

Synthesis of Diamond Spheres

Lee

Baik

Lee

et al. 2004

Chemical Vapor Deposition

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Diamond synthesized by CVD can be produced in different forms ranging from ballas material through to single crystal and polycrystalline films.[1±5] Diamond powders produced by conventional high-pressure/high-temperature or explosive methods are generally non-uniform and irregularly shaped. In this paper we describe the synthesis, using CVD, of diamond powders that are spherical and monodisperse, with diameters in the range 150±600 nm. Gas-phase nucleation [6±8] has been induced using a multi-cathode direct current plasma [9,10] in which the nanoscale diamond powders accumulate on a copper substrate. Transmission electron microscopy (TEM) patterns show that the internal structure comprises nanocrystalline diamond grains exhibiting a Raman peak at 1334 cm ±1 . This new form of diamond has many potential applications, including novel abrasives, cold cathode emitters, and drug delivery systems. Previously, polycrystalline diamond films have been deposited using a multi-cathode direct current (MCDC) plasma-activated (PA) CVD reactor. [9,10] With such a reactor (shown in Fig. 1a) diamond powders were also observed at the circumference of the copper disk. The presence of the copper disk lowered the surface temperature (<750 K) to a value where the diamond growth rate was negligible. As a result, it also yielded a suitable temperature gradient for the gas-phase nucleation of diamond outside the plasma boundary. The specified temperature gradient corresponds to a direction perpendicular to the lower substrate extending into the gas phase but just outside the plasma region. In the case where the tungsten anode was removed and the copper temperature was again reduced below 750 K, graphitic particles were co-deposited with diamond powder inside the plasma zone, on which the electric field concentrated, leading eventually to an arc discharge. [9,10] This caused an increase in the temperature resulting in localized film growth around the graphitic particles. Altering the configuration to that shown in Figure 1b restricted the individual DC plasmas to the regions between each pair of electrodes. Instead of the normal substrate, shown in Figure 1a, seven molybdenum disks (15 mm in Communications

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Real and apparent grain sizes in chemical vapor deposited diamond

Cited by 14 publications

References 14 publications

Magic-Sized Diamond Nanocrystals

Magic-Sized Diamond Nanocrystals

Raman Imaging and Kelvin Probe Microscopy for the Examination of the Heterogeneity of Doping in Polycrystalline Boron-Doped Diamond Electrodes

Synthesis of Diamond Spheres

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