| 1. |
- Rasheed, M. N., et al.
(författare)
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Enhanced electrical properties of nonstructural cubic silicon carbide with graphene contact for photovoltaic applications
- 2020
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Ingår i: Digest Journal of Nanomaterials and Biostructures. - Bucharest, Romania : S.C. Virtual Company of Phisics S.R.L. - 1842-3582. ; 15:3, s. 963-972
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Tidskriftsartikel (refereegranskat)abstract
- Cubic silicon carbide (3C-SiC) is successfully synthesized through a simple solid-state reaction technique at a comparatively low temperature without using any catalyst. The XRD data is also used to study other structural parameters of synthesized sample by using different method. Raman peak at 796 cm(-1) supports the XRD results. Si-C vibrational mode observed at 788 cm-1 in the FTIR spectrum further confirms the growth of 3C-SiC. UV-Vis spectroscopy is used to measure optical bandgap energy (E-g = 2.36 eV). Other optical parameters such as dielectric constant and refractive index of grown sample are also studied. Electrical performance is analyzed by using graphene contact with further evaluation of dark and light IV-measurements. The use of graphene contact establishes the enhancement of electrical conductivity of as-grown samples particularly when they are exposed to light. These findings indicate that the grown sample has comparatively better transport properties than conventional metal contacts under the illuminated conditions.
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| 2. |
- Schuh, P., et al.
(författare)
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Sublimation growth of bulk 3C-SiC using 3C-SiC-on-Si (100) seeding layers
- 2017
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Ingår i: Journal of Crystal Growth. - : ELSEVIER SCIENCE BV. - 0022-0248 .- 1873-5002. ; 478, s. 159-162
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a transfer process of 3C-SiC-on-Si (100) seeding layers grown by chemical vapor deposition onto a poly-or single-crystalline SiC carrier. Applying subsequent sublimation growth of SiC in [100] direction resulting in large area crystals (up to approximate to 11 cm(2)) with a thickness of up to approximately 850 lm. Raman spectroscopy, Laue X-ray diffraction and electron-backscattering-diffraction revealed a high material quality in terms of single-crystallinity without secondary polytype inclusions, antiphase boundaries or double positioning grain boundaries. Defects in the bulk grown 3C-SiC, like protrusions with surrounding stressed areas, stem from the epitaxial seeding layer. The presented concept using 3C-SiC-on-Si seeding layers reveals a path for the growth of bulk 3C-SiC crystals. (C) 2017 Elsevier B.V. All rights reserved.
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| 3. |
- Yang, M., et al.
(författare)
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Puddle-Induced Resistance Oscillations in the Breakdown of the Graphene Quantum Hall Effect
- 2016
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 117:23
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Tidskriftsartikel (refereegranskat)abstract
- We report on the stability of the quantum Hall plateau in wide Hall bars made from a chemically gated graphene film grown on SiC. The v = 2 quantized plateau appears from fields B similar or equal to 5 T and persists up to B similar or equal to 80 T. At high current density, in the breakdown regime, the longitudinal resistance oscillates with a 1/B periodicity and an anomalous phase, which we relate to the presence of additional electron reservoirs. The high field experimental data suggest that these reservoirs induce a continuous increase of the carrier density up to the highest available magnetic field, thus enlarging the quantum plateaus. These in-plane inhomogeneities, in the form of high carrier density graphene pockets, modulate the quantum Hall effect breakdown and decrease the breakdown current.
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| 4. |
- Gavryushin, V., et al.
(författare)
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Examination of Photoluminescence Temperature Dependencies in N-B Co-doped 6H-SiC
- 2014
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Ingår i: IOP Conference Series. - : Institute of Physics Publishing (IOPP). - 1757-8981 .- 1757-899X. ; 56:1, s. 012003-
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Tidskriftsartikel (refereegranskat)abstract
- Two overlapping photoluminescent (PL) bands with a peaks (half-width) at 1.95 eV (0.45 eV) and 2.15 eV (0.25 eV), correspondingly at 300 K, are observed in heavily B-N co-doped 6H-SiC epilayers under high-level excitation condition. The low energy band dominates at low temperatures and decreases towards 300 K which is assigned to DAP emission from the nitrogen trap to the deep boron (dB) with phonon-assistance. The 2.15 eV band slightly increases with temperature and becomes comparable with the former one at 300 K. We present a modelling comprising electron de-trapping from the N-trap, i.e. calculating trapping and de-trapping probabilities. The T-dependence of the 2.15 eV band can be explained by free electron emission from the conduction band into the dB center provided by similar phonon-assistance
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| 5. |
- Grivickas, V., et al.
(författare)
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Carrier lifetimes and influence of in-grown defects in N-B Co-doped 6H-SiC
- 2014
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Ingår i: IOP Conference Series. - : Institute of Physics Publishing (IOPP). ; 56:1, s. 012004-
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Konferensbidrag (refereegranskat)abstract
- The thick N-B co-doped epilayers were grown by the fast sublimation growth method and the depth-resolved carrier lifetimes have been investigated by means of the free-carrier absorption (FCA) decay under perpendicular probe-pump measurement geometry. In some samples, we optically reveal in-grown carbon inclusions and polycrystalline defects of substantial concentration and show that these defects slow down excess carrier lifetime and prevent donor-acceptor pair photo luminescence (DAP PL). A pronounced electron lifetime reduction when injection level approaches the doping level was observed. It is caused by diffusion driven non-radiative recombination. However, the influence of surface recombination is small and insignificant at 300 K.
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| 6. |
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| 7. |
- Maryam, A., et al.
(författare)
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Preparation and application of LiSiC-oxide for low temperature solid oxide fuel cells
- 2021
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Ingår i: Digest Journal of Nanomaterials and Biostructures. - : VIRTUAL CO PHYSICS SRL. - 1842-3582. ; 16:2, s. 501-508
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductors are well known as excellent materials in the field of exploring novel avenues which combine various fields in electronics, electrochemistry, etc for new functional device concepts. Lithium silicon carbide (LiSiC) is a well-known electrode material for Lithium ion batteries but relatively new for solid oxide fuel cells (SOFCs) and electrolyte-layer free fuel cells (EFFCs). In the present work, we have explored three categories of fuel cells based on mixed LiSiC-SDC (samarium doped ceria) in SOFC and LiSiC as a single component material with type (I) and without coating of a layer of 3C-SiC as EFFC type (II). All of three cells are sandwiched between Ni foams coated with NCAL (Ni0.8Co0.15Al0.05Li-oxide). The electrochemical performances of as prepared fuel cells are tested at 550 degrees C, which is substantially lower than in conventional fuel cell materials. The LiSiC based EFFC type (II) demonstrates better performance because of less ohmic resistance as compared to type (I) have more layers. This indicates that the LiSiC-SDC system has potential for fuel cell development in accordance with energy band structure and alignment.
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| 8. |
- Ou, H., et al.
(författare)
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Fluorescent SiC for white light-emitting diodes
- 2012
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Ingår i: Asia Commun. Photonics Conf.. - Washington, D.C. : OSA.
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Konferensbidrag (refereegranskat)abstract
- The strong photoluminescence from f-SiC was achieved after the optimization of the B and N concentrations. Surface nanostructures were successfully applied to enhance the extraction efficiency. f-SiC is a promising wavelength convertor for white LEDs.
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| 9. |
- Strokan, N.B., et al.
(författare)
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Detection of strongly and weakly ionizing radiation by triode structure based on SIC films
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:9, s. 5714-5719
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Tidskriftsartikel (refereegranskat)abstract
- The detection of strongly and weakly ionizing radiation by triode structure based on silicon carbide (SiC) films was discussed. The possibility of alpha particle spectrometry in spite of slow carrier transport via diffusion was demonstrated. Analysis showed that the signal generated by weakly ionizing radiation incident on a film had low amplitude.
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| 10. |
- Syväjärvi, Mikael, et al.
(författare)
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Growth of 6H and 4H-SiC by sublimation epitaxy
- 1999
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Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 197:1-2, s. 155-162
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Tidskriftsartikel (refereegranskat)abstract
- The epitaxial sublimation growth process of SiC has been investigated. Layers with specular surfaces and growth rates up to 2 mm/h have been obtained. No step bunching is observed by optical microscopy even on very thick layers which indicates a stable step growth mechanism. Under certain growth conditions the morphology degrades. The morphological stability is investigated and discussed in relation to the growth kinetics. Impurities in the epitaxial layers are investigated by secondary ion mass spectroscopy and low-temperature photoluminescence. The carrier concentration is measured by capacitance–voltage measurements. The structural quality of the grown material is improved compared to the substrate as shown by X-ray diffraction measurements.
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