Reducing the grain size for fabrication of nanocrystalline diamond films

Jiang, Nan; Sugimoto, K; Eguchi, K.; Inaoka, Takeshi; Shintani, Yoshihiro; Makita, H.; Hatta, Akimitsu; Hiraki, Akio

doi:10.1016/s0022-0248(00)00972-6

Cited by 36 publications

(23 citation statements)

References 10 publications

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“…[21][22][23][24][25][26] The application of negative bias voltage in CH 4 / H 2 plasma attracts the positively charged species, such as H þ , CH 3 þ , CH þ and expels the electrons that markedly alter the plasma chemistry near the substrates. [21][22][23][24][25][26] Shigesato et al 48 found that negative biasing increased the concentration of atomic hydrogen in the CH 4 /H 2 plasma and proposed that this could cause preferential etching of sp 2 -bonded C. On the other hand, Robertson et al 49 proposed that ion subplantation due to applied negative bias causes deposition of nanocrystalline graphitic C, and that diamond nucleates where the graphitic planes are locally oriented perpendicular to the surface. Zhong et al 25 described that during negative bias in CH 4 /H 2 plasma, the diamond grains were formed easier than on graphitic phases, so the diamond grains grow rapidly covering the graphitic phases, minimizing the influence of the nucleation sites of the graphitic phases on the subsequent growth process of the diamond grains.…”

Section: Discussionmentioning

confidence: 99%

“…A few earlier reports [21][22][23][24][25] observed that the application of bias voltage in the CH 4 /H 2 plasma-based microwave plasma enhanced CVD (MPECVD) process not only facilitated the growth of diamond, but also efficiently reduced the size of the grains, resulting in diamond films with nanosized granular structure. In addition, Teng et al 26 reported the enhanced EFE behavior of bias-enhanced grown (BEG) nanocrystalline diamond (NCD) films using CH 4 CH 4 /H 2 plasma and the feasibility of bias enhanced growth of UNCD films using CH 4 /Ar plasma has not been reported yet.…”

Section: /Ar Plasma I Introductionmentioning

confidence: 99%

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Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Sankaran

Huang

Saravanan

et al. 2014

Journal of Applied Physics

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Microstructural evolution of bias-enhanced grown (BEG) ultrananocrystalline diamond (UNCD) films has been investigated using microwave plasma enhanced chemical vapor deposition in gas mixtures of CH4 and Ar under different negative bias voltages ranging from −50 to −200 V. Scanning electron microscopy and Raman spectroscopy were used to characterize the morphology, growth rate, and chemical bonding of the synthesized films. Transmission electron microscopic investigation reveals that the application of bias voltage induced the formation of the nanographitic filaments in the grain boundaries of the films, in addition to the reduction of the size of diamond grains to ultra-nanosized granular structured grains. For BEG-UNCD films under −200 V, the electron field emission (EFE) process can be turned on at a field as small as 4.08 V/μm, attaining a EFE current density as large as 3.19 mA/cm2 at an applied field of 8.64 V/μm. But the films grown without bias (0 V) have mostly amorphous carbon phases in the grain boundaries, possessing poorer EFE than those of the films grown using bias. Consequently, the induction of nanographitic filaments in grain boundaries of UNCD films grown in CH4/Ar plasma due to large applied bias voltage of −200 V is the prime factor, which possibly forms interconnected paths for facilitating the transport of electrons that markedly enhance the EFE properties.

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Section: Discussionmentioning

confidence: 99%

Section: /Ar Plasma I Introductionmentioning

confidence: 99%

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Sankaran

Huang

Saravanan

et al. 2014

Journal of Applied Physics

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“…13 Astronomical observations suggest that nanodiamonds are present in the protoplanetary disks of certain types of stars, 14,15 although the origins of these cosmic sources are still under investigation. Various research groups [16][17][18][19][20] have been major contributors to NCD research over the past decade. There has been enhancement in diamond nucleation density of several orders of magnitude using various pretreatment methods such as mechanical abrasion techniques (scratching), 21 ultrasonic particle treatment (micro-chipping), 22 carbon, carbide and carbide forming interlayers, 23 bias enhanced nucleation (BEN), 24 seeding with diamond nano-particles, 25 etc., but at the same time, the surface alteration or damage 23 and contamination of the substrate surface in varying degrees as a result of any kind of pre-treatment cannot be overruled and is inevitable.…”

Section: Introductionmentioning

confidence: 99%

New route to the fabrication of nanocrystalline diamond films

Varshney

Palomino

Gil

et al. 2014

Journal of Applied Physics

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Nanocrystalline diamond (NCD) thin films offer applications in various fields, but the existing synthetic approaches are cumbersome and destructive. A major breakthrough has been achieved by our group in the direction of a non-destructive, scalable, and economic process of NCD thin-film fabrication. Here, we report a cheap precursor for the growth of nanocrystalline diamond in the form of paraffin wax. We show that NCD thin films can be fabricated on a copper support by using simple, commonplace paraffin wax under reaction conditions of Hot Filament Chemical Vapor Deposition (HFCVD). Surprisingly, even the presence of any catalyst or seeding that has been conventionally used in the state-of-the-art is not required. The structure of the obtained films was analyzed by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy and electron energy-loss spectroscopy recorded at the carbon K-edge region confirm the presence of nanocrystalline diamond. The process is a significant step towards cost-effective and non-cumbersome fabrication of nanocrystalline diamond thin films for commercial production.

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“…Especially, there is an increasing interest in using the nanostructured carbon films as the cold cathode emitters for their promising application in displays, highbrightness lamps and other microelectronic devices [5]. Researchers have been making their efforts to exploit the different processes for the fabrication of efficient nanostructured carbon materials such as nanodiamond [6], CNTs [7] and carbon nanoparticles (CNPs) [8] to meet these goals. Jiang et al [6] produced nanocrystalline diamond films by bias growth technique using a microwave plasma CVD equipment and indicated that the nanocrystalline diamond films presented better field emission properties than the conventional microcrystalline diamond films.…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have been making their efforts to exploit the different processes for the fabrication of efficient nanostructured carbon materials such as nanodiamond [6], CNTs [7] and carbon nanoparticles (CNPs) [8] to meet these goals. Jiang et al [6] produced nanocrystalline diamond films by bias growth technique using a microwave plasma CVD equipment and indicated that the nanocrystalline diamond films presented better field emission properties than the conventional microcrystalline diamond films. Satyanarayana et al [8] prepared CNPs by the cathodic arc method, and their results showed that CNPs exhibited promising field emission characteristics.…”

Section: Introductionmentioning

confidence: 99%