Analytical TEM study of CVD diamond growth on TiO2 sol–gel layers

Lu, Ying-Gang; Verbeeck, Johan; Turner, Stuart; Hardy, An; Janssens, Stoffel D.; Dobbelaere, Christopher De; Wagner, Patrick; Bael, Marlies K. Van; Haenen, Ken; Tendeloo, Gustaaf Van

doi:10.1016/j.diamond.2012.01.022

Cited by 16 publications

(11 citation statements)

References 40 publications

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“…The film decreases duration of diamond nucleation phase by effective Ti‐C reactions and enhance nucleation by slight increase of surface roughness. The enhancement of nucleation by means of interlayers and roughness induced effects has been shown by a number of authors . A very thin (monoatomic) transition layer of titanium dioxide (TiO 2 ), due to its refractive index close to the one of diamond, may reduce the optical effect, mainly reflection, caused by the introduction of such layer to optical sensors.…”

Section: Introductionmentioning

confidence: 99%

Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer

Bogdanowicz

Śmietana

Gnyba

et al. 2013

Physica Status Solidi (a)

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Nucleation and growth processes of thin diamond films on fused silica optical fibres have been investigated. Fibres were coated with diamond film using microwave plasma enhanced chemical vapour deposition (mPE CVD) system. Since the growth of diamond on the fused silica glass requires high seeding density, two types of glass pre-treatment were applied: titanium dioxide (TiO 2 ) interlayer deposition and sonication in nanodiamond suspension. In the experiment, high density, thin ($20 nm) TiO 2 films were deposited using high-power impulse magnetron sputtering. Subsequently, a set of thin diamond films deposited in up to 60 min-long process was investigated. Results obtained for the two pre-treatment methods were compared. The nucleation processes were studied and compared using numerical analysis of scanning electron microscopy (SEM) images. The molecular structure of nucleated diamond was examined with micro-Raman spectroscopy. The sp 3 /sp 2 ratio was calculated using Raman spectra deconvolution method. Thickness, roughness and optical properties of the nanodiamond films in VIS-NIR wavelength range were investigated by means of spectroscopic ellipsometry. It was found that the high density TiO 2 interlayer enhances CVD diamond film nucleation processes on fused silica and increases sp 3 /sp 2 ratio of the film. The proposed growth method can be effectively applied in manufacturing of various types of optical fibre sensors. Due to high chemical and mechanical resistance of the diamond films such optical sensors are highly desired.

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Section: Introductionmentioning

confidence: 99%

Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer

Bogdanowicz

Śmietana

Gnyba

et al. 2013

Physica Status Solidi (a)

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“…This carbon diffusion and conversion from diamond to amorphous carbon made the seed areas below the TiO 2 layer grow and bend the TiO 2 layer upwards to create the nucleation center of the diamond film. 65 These recent findings strongly support the crucial role of carbon diffusion in the diamond nucleation and film formation stages. In conclusion, it is expected that the carburization and the fast accumulation of carbon atoms within the subsurface region of all the seed nanolayers of the Group 4-6 transition metals under investigation in this study, in combination with the number density of initially embedded ND particle seeds, determine the nucleation rate of diamond.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 55%

Metallic Seed Nanolayers for Enhanced Nucleation of Nanocrystalline Diamond Thin Films

et al. 2013

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ABSTRACT:The enhancement of the nucleation and subsequent growth of nanocrystalline diamond (NCD) films with a submicron thickness control on silicon substrates is demonstrated by using a sputter deposition of six different metallic (Cr, Mo, Nb, Ti, V, and W) seed nanolayers. The effectiveness of altered surface morphology and surface chemistry is discussed. We show that the number density of nanodiamond particles embedded on the nanorough metallic surfaces after an ultrasonic seeding step together with the dynamic surface chemistry during hot-filament chemical vapor deposition of diamond determine the nucleation kinetics, microstructure and surface topography of the NCD films. Overall, the smoothest NCD layer (root-mean-square roughness 10 nm) was obtained with the highest seed density of diamond nanoparticles anchored to the metallic (W) surface. In particular, the rapid carbide-forming metals Mo, Nb and W showed the highest number density of diamond crystallites formed during the NCD nucleation stage, which resulted in dense, uniform and very smooth NCD films. Much rougher NCD films (17-37 nm) were obtained on the Cr, Ti, and V nanolayers that did not form carbides rapidly.Importantly, the carbon phase purity of the grown NCD films remains unaffected by the presence of different metallic seed nanolayers. Furthermore, we have assessed that the metallic nanolayer surface morphology does not play a relevant role in the enhancement of the seeding step.

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“…It essentially provided a full encapsulation of the substrate. Before deposition the silicon was pre‐treated by with a colloidal suspension of 5–10 nm detonation diamond (NanoCarbon Institute Co., Ltd., Japan) to increase diamond nucleation 20. After the first deposition run, covering one side of the substrate, this procedure was repeated to ensure a high seeding density at the other side, still showing the uncovered silicon substrate.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical oxidation of ionic liquids at highly boron doped diamond electrodes

Fabiańska¹,

Ossowski²,

Bogdanowicz³

et al. 2012

Physica Status Solidi (a)

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An electrochemical oxidation using a highly boron‐doped diamond (BDD) electrode has been tested for the treatment of solutions containing ionic liquids (ILs). The double‐sided Si/highly BDD electrodes were synthesized by microwave plasma enhanced chemical vapour deposition (MW PE CVD). Investigation of the electrode surface with scanning electron microscopy (SEM) confirmed that the synthesized layers were continuous and formed densely packed grain structure. The structure of BDD was confirmed by Raman spectra analysis. The effect of IL structure as the kind of electrolyte (Na2SO4 and NaCl) has been investigated. Electrolyses were conducted in an undivided electrolytic cell under galvanostatic conditions. The efficiency of the process has been evaluated in terms of variations of IL concentrations and chemical oxygen demand (COD) removal. Results show that pyridinium ILs were easier removed than imidazolium salts. The intermediates of electrochemical degradation of 1‐butyl‐3‐methylimidazolium salt were detected, and IL degradation pathway was proposed based on the analytical results. It was suggested that •OH radicals produced by water electrolysis attacked IL to form its derivatives with keto groups substituted to imidazolium ring. These compounds underwent ring breakage, which led to the formation of aliphatic acids that were eventually mineralized by electrolysis to CO2. Other by‐products were obtained by cutting one of the side chains substituted to N atoms in imidazolium ring. Additionally in NaCl electrolyte chloroorganic by‐products were identified.

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Analytical TEM study of CVD diamond growth on TiO2 sol–gel layers

Cited by 16 publications

References 40 publications

Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer

Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer

Metallic Seed Nanolayers for Enhanced Nucleation of Nanocrystalline Diamond Thin Films

Electrochemical oxidation of ionic liquids at highly boron doped diamond electrodes

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