SiC, from Amorphous to Nanosized Materials, the Exemple of SiC Fibres Issued of Polymer Precursors

Colomban, Philippe

doi:10.5772/24347

Cited by 7 publications

(5 citation statements)

References 123 publications

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“…For a SiC-converted batch of superlattices, approximately 20–30 superlattice samples were randomly chosen and examined. Most samples displayed diffuse peaks around 400 and 800 cm –1 corresponding to small domains of SiC crystallites (Figure c) . However, for a portion of the population, approximately 5%, the spectrum displayed a peak between 515 and 520 nm (Figure d) that corresponds to silicon crystallites.…”

Section: Resultsmentioning

confidence: 99%

Engineered Silicon Carbide Three-Dimensional Frameworks through DNA-Prescribed Assembly

et al. 2021

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The ability to create nanoengineered silicon carbide (SiC) architectures is important for the diversity of optical, electronic, and mechanical applications. Here, we report a fabrication of periodic three-dimensional (3D) SiC nanoscale architectures using a self-assembled and designed 3D DNA-based framework. The assembly is followed by the templating into silica and subsequent conversion into SiC using a lower temperature pathway (<700 °C) via magnesium reduction. The formed SiC framework lattice has a unit size of about 50 nm and domains over 5 μm, and it preserves the integrity of the original 3D DNA lattice. The spectroscopic and electron microscopy characterizations reveal SiC crystalline morphology of 3D nanoarchitectured lattices, whereas electrical probing shows 2 orders of magnitude enhancements of electrical conductivity over the precursor silica framework. The reported approach offers a versatile methodology toward creating highly structured and spatially prescribed SiC nanoarchitectures through the DNA-programmable assembly and the combination of templating processes.

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Section: Resultsmentioning

confidence: 99%

Engineered Silicon Carbide Three-Dimensional Frameworks through DNA-Prescribed Assembly

et al. 2021

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“…The amorphous state guarantees great homogeneity but the density of bonds per unit of volume is lower than that of crystalline counterpart. Therefore, the intermediate state between the glassy and crystalline state is a good compromise and has been sought for ceramic fibers [83,84,118,[137][138][139].…”

Section: Carbides Nitrides Etcmentioning

confidence: 99%

“…The unique combination of thermal and mechanical properties exhibited by (oxy)carbides and (oxy)nitrides has proven itself in the applications of the electronics, automotive, defense and aerospace industries [32,33,118,123,133]. The successful conversion of their properties to end applications lies in the manufacture of these ceramics into fully dense microstructures.…”

Section: Carbides Nitrides Etcmentioning

confidence: 99%

Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

Colomban

2020

Ceramics

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Chemically and thermally stable ceramics are required for many applications. Many characteristics (electrochemical stability, high thermomechanical properties, etc.) directly or indirectly imply the use of refractory materials. Many devices require the association of different materials with variable melting/decomposition temperatures, which requires their co-firing at a common temperature, far from being the most efficient for materials prepared by conventional routes (materials having the stability lowest temperature determines the maximal firing temperature). We review here the different strategies that can be implemented to lower the sintering temperature by means of chemical preparation routes of oxides, (oxy)carbides, and (oxy)nitrides: wet chemical and sol–gel process, metal-organic precursors, control of heterogeneity and composition, transient liquid phase at the grain boundaries, microwave sintering, etc. Examples are chosen from fibers and ceramic matrix composites (CMCs), (opto-)ferroelectric, electrolytes and electrode materials for energy storage and production devices (beta alumina, ferrites, zirconia, ceria, zirconates, phosphates, and Na superionic conductor (NASICON)) which have specific requirements due to multivalent composition and non-stoichiometry.

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“…The figure shows three distinct broad bands in the regions of 200-700 cm −1 , 700-1200 cm −1 and 1300-1600 cm −1 . The 200-600 cm −1 band is attributed to activation of Raman modes related to acoustic phonons of a-SiC [27,38] or that of amorphous silicon (a-Si) [39] or their combination. The 3C-SiC (β SiC/cubic phase) exhibits the transverse optical (TO) and longitudinal (LO) optical Raman modes around 790 cm −1 and 960 cm −1 respectively [40].…”

Section: Structural and Compositional Properties Of A-sic Thin Filmsmentioning

confidence: 99%

“…The right hand side of respective figure contain the list of each peak position obtained from deconvolution. The peaks within broad bands in the regions of 200-700 cm −1 which corresponds to acoustic (LA and TA) Raman modes of a-SiC overlapped with Raman modes (TO, LO, LA and TA) of a-Si marked as region I[38,39], while those within spectral region 700-1200 cm −1 corresponding optical Raman modes of a-SiC are marked as region II and peaks within 1300-1600 cm −1 corresponding to C-C bonds are marked as region III. The third broadband region marked as III in the figures, is attributed to Raman modes arising from amorphous C containing mixed phase of sp 3 -sp 2 with random covalent network of tetrahedral-trigonal bonds characterised by distorted bond angles and bond lengths[41].…”

mentioning

confidence: 98%

Tailoring of stoichiometry and band-tail emission in PLD a-SiC thin films by varying He deposition pressure

Dey

Khare

2020

SN Appl. Sci.

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The present work focuses on the effect of He pressure (vacuum, 10 −2 -5 mbar) on structural and optical properties of amorphous silicon carbide (a-SiC) thin films, deposited by pulsed laser deposition (PLD) technique onto fused silica. A stoichiometric change occurs in PLD a-SiC film, with increasing He deposition pressure, transforming a near stoichiometric SiC material to C-rich SiC films till 1 mbar of He pressure followed by drastic decrease in carbon (C) content at 5 mbar. The optical band gap of the films estimated using Tauc plot from UV-Vis-NIR transmittance spectra showed initial increase from 2.09 to 2.61 eV with increasing He pressure from 10 −6 to 1 mbar, then decrease to 2.11 eV at 5 mbar. A broad band photoluminescence (PL) peak featured in each of the a-SiC films at room temperature. The PL spectra exhibited blue shift in peak energy from 1.8 to 2.2 eV with increase in atomic percentage of C from 49.4 to 62.4%. The origin of the PL exhibited in these films is clearly due to band tail emissions from amorphous SiC structures which has been explained by the observed variation of PL intensity and corresponding FWHM with band gap as well as Urbach energy.

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SiC, from Amorphous to Nanosized Materials, the Exemple of SiC Fibres Issued of Polymer Precursors

Cited by 7 publications

References 123 publications

Engineered Silicon Carbide Three-Dimensional Frameworks through DNA-Prescribed Assembly

Engineered Silicon Carbide Three-Dimensional Frameworks through DNA-Prescribed Assembly

Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

Tailoring of stoichiometry and band-tail emission in PLD a-SiC thin films by varying He deposition pressure

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