Comparison of the growth and properties of ultrananocrystalline diamond and nanocrystalline diamond

Williams, Oliver A.; Daenen, Michaël; D’Haen, Jan; Haenen, Ken; Maes, Jochen; Moshchalkov, Victor; Nesládek, Miloš; Gruen, D. M.

doi:10.1016/j.diamond.2005.12.009

Cited by 163 publications

(126 citation statements)

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“…A reference film (S1) was grown in a boron-free reactor. It was confirmed that the method applied for seeding has an important impact on the quality of the NCD films 14 and thus, the efficiency of doping can be increased: see for instance the properties of samples S4, seeded mechanically and with 150 ppm of TMB in the gas phase, and S5, seeded in ultrasonic bath with 10 ppm of TMB in the gas phase.…”

Section: A Structural Propertiesmentioning

confidence: 79%

“…This is not surprising, since the density of grain boundaries in UNCD is larger due to the smaller grain size. 14,32 Grain boundaries were already suggested to have a strong influence on Raman characterization as well as in the electronic properties of UNCD films. 32 As in the case of the first order diamond line, both the D and G bands shifts slightly towards lower wavenumbers with the increase of the boron doping level.…”

Section: A Structural Propertiesmentioning

confidence: 99%

“…12, 13 The growth and structural properties of NCD films and ultrananocrystalline diamond (UNCD) films have been recently compared. 14 So far, the n-type conductivity induced by nitrogen addition during UNCD growth has been investigated in detail. 15,16 The p-type doping of diamond with boron has been extensively examined in single crystal (SCD) homoepitaxially grown material, 17,18,19,20 as well as in polycrystalline materials (PCD).…”

Section: Introductionmentioning

confidence: 99%

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Electronic and optical properties of boron-doped nanocrystalline diamond films

et al. 2009

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We report on the electronic and optical properties of boron-doped nanocrystalline diamond (NCD) thin films grown on quartz substrates by CH 4 /H 2 plasma chemical vapor deposition.Diamond thin films with a thickness below 350 nm and with boron concentration ranging from 10 17 cm -3 to 10 21 cm -3 have been investigated. UV Raman spectroscopy and AFM have been used to assess the quality and morphology of the diamond films. Hall effect measurements confirmed the expected p-type conductivity. At room temperature, the conductivity varies from 1.5x10 -8 Ω -1 cm -1 for a non-intentionally doped film up to 76 Ω -1 cm -1 for a heavily B-doped film. Increasing the doping level results in a higher carrier concentration while the mobility decreases from 1.8 cm 2 V -1 s -1 down to 0.2 cm 2 V -1 s -1 . For NCD films with low boron concentration, the conductivity strongly depends on temperature. However, the conductivity and the carrier concentration are no longer temperature-dependent for films with the highest boron doping, and the NCD films exhibit metallic properties. Highly doped films show superconducting properties with critical temperatures up to 2K. The critical boron concentration for the metal-insulator transition is in the range from 2x10 20 cm -3 up to 3x10 20 cm -3 . We discuss different transport mechanisms to explain the influence of the grain boundaries and boron doping on the electronic properties of NCD films. Valence band transport dominates at low boron concentration and high temperatures, 2 whereas hopping between boron acceptors is the dominant transport mechanism for boron doping concentration close to the Mott transition. Grain boundaries strongly reduce the mobility for low and very high doping levels. However, at intermediate doping levels where hopping transport is important, grain boundaries have a less pronounced effect on the mobility. The influence of boron and the effect of grain boundaries on the optoelectronic properties of the NCD films are examined using spectrally resolved photocurrent measurements and photothermal deflection spectroscopy. Major differences occur in the low energy range, between 0.5 -1.0 eV, where both Boron impurities and the sp 2 carbon phase in the grain boundaries govern the optical absorption.

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Section: A Structural Propertiesmentioning

confidence: 79%

Section: A Structural Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electronic and optical properties of boron-doped nanocrystalline diamond films

et al. 2009

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“…react with the non-diamond carbon and hydrocarbons, which leads to gaseous products that are able to be pumped away. As NCD was considered as a thinner version of MCD, [44], previous work using similar deposition conditions to that of MCD have been used to produce NCD, which may lead to high levels of sp2 impurities. For example, reactor pressures were usually set high, typically > 30 Torr.…”

Section: Role Of Hydrogenmentioning

confidence: 99%

Boron-doped ultrananocrystalline diamond synthesized with an H-rich/Ar-lean gas system

Zeng

Konicek

Moldovan

et al. 2015

Carbon

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This paper reports the recent development and applications of conductive borondoped ultrananocrystalline diamond (BD-UNCD). The authors have determined that BD-UNCD can be synthesized with an H-rich gaseous chemistry and a high CH 4 /H 2 ratio, which is opposite to previously reported methods with Ar-rich or H-rich gas compositions but utilizing very low CH 4 /H 2 ratio. The BD-UNCD has a resistivity as low as 0.01 ohm·cm, with low roughness (down to several nm) and a wide deposition temperature range (450-850¼C).The properties of this BD-UNCD were studied systematically using resistivity characterization, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and roughness measurements. Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy confirms that up to 97% of the UNCD is deposited as sp3 carbon.These series of measurements also reveal additional unique properties for this material, such as an ÒMÓ shape Raman signature, line-granular nano-cluster texture and high C-H bond surface content. A hypothesis is provided to explain why this new deposition strategy, with H-rich/Ar-free gas chemistry and CH 4 /H 2 ratio, is able to produce high sp3-content and/or 2 heavily doped UNCD. In addition, a few emerging applications for BD-UNCD in the field of atomic force microscopy, electrochemistry and biosensing are reviewed here.

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“…Polycrystalline diamond films, among which ultrananocrystalline and nanocrystalline diamond (UNCD and NCD, respectively), produced by plasma deposition, have very promising tribological, biological and electrical applications [49][50][51]. NCD films are typically grown under conventional diamond PE-CVD conditions, i.e., a CH 4 /H 2 mixture at a ratio 1/99, and a substrate temperature above 1000 K [52], resulting in columnar diamond crystals with diameters below 500 nm [51].…”

Section: Modeling the Plasma Chemistry For The Growth Of Nanostructurmentioning

confidence: 99%

Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials

Bogaerts¹,

Eckert²,

Mao³

et al. 2011

J. Phys. D: Appl. Phys.

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In this review paper, an overview is given of different modeling efforts for plasmas used for the formation and growth of nanostructured materials. This includes both the plasma chemistry, providing information on the precursors for nanostructure formation, as well as the growth processes itself. We limit ourselves to carbon (and silicon) nanostructures. Examples of the plasma modeling comprise nanoparticle formation in silane and hydrocarbon plasmas, as well as the plasma chemistry giving rise to carbon nanostructure formation, such as (ultra)nanocrystalline diamond ((U)NCD) and carbon nanotubes (CNTs). The second part of the paper deals with the simulation of the (plasma-based) growth mechanisms of the same carbon nanostructures, i.e., (U)NCD and CNTs, both by mechanistic modeling and detailed atomistic simulations. IntroductionLow temperature plasmas are playing an increasingly important role for the formation and growth of nanostructures and nanostructured materials (e.g., [1][2][3][4][5][6][7]). To improve the performance of these plasma growth processes, a good insight is desired in the plasma and in the interaction with the growing nanostructures. This insight can be obtained by experimental research, but the latter is not always straightforward, in view of the small dimensions of the nanomaterials and the possible disturbance of the plasma characteristics, e.g., when introducing a probe. Therefore, computer simulations can be very useful to assist in the experimental developments.In the present paper, we will give an overview of different modeling efforts that have been presented in the literature for plasmas used for nanostructure formation. This includes two different aspects. First, a thorough understanding of the plasma behavior is needed. This comprises background gas flow and heating (i.e., fluid dynamics), gas breakdown, transport and heating of the electrons and the so-called heavy particles, as well as the plasma chemistry, i.e., creation and destruction of the various plasma species by chemical reactions. Modeling of the plasma chemistry can give indications on which species are important precursors for the growth of nanostructured materials and how the plasma operating conditions can be tuned to optimize the growth process. Therefore, in this paper we will mainly focus on the plasma chemistry modeling. Several plasma modeling approaches exist in literature, such as analytical models, zero-dimensional (0D) chemical kinetics simulations, fluid models (describing the chemical kinetics as well as fluid dynamics), solving the Boltzmann transport equation, Monte Carlo (MC) and particle-in-cell (PIC)-MC simulations, as well as hybrid methods, combining the above (e.g., MC + fluid) models. For describing the plasma chemistry, the 0D chemical kinetics approach is often applied, as it can take into account a large number of different species and reactions without too much computational effort. However, it assumes a spatially uniform plasma composition and does not consider transport of the plasm...

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Comparison of the growth and properties of ultrananocrystalline diamond and nanocrystalline diamond

Cited by 163 publications

References 12 publications

Electronic and optical properties of boron-doped nanocrystalline diamond films

Electronic and optical properties of boron-doped nanocrystalline diamond films

Boron-doped ultrananocrystalline diamond synthesized with an H-rich/Ar-lean gas system

Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials

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