Investigation of potential of vacuum-free femtosecond laser sintering for direct printing using silicon carbide nanoparticles without inorganic binder

Kawabori, Tatsuru*; Watanabe, Masashi; Imai, Yoshiyuki; Ueta, Shohei; Yan, X.; Mizoshiri, Mizue*

Applied Physics A, 129(7), p.498_1 - 498_9, 2023/07

https://doi.org/10.1007/s00339-023-06774-z

We investigated a potential of femtosecond laser sintering of silicon carbide (SiC) using the nanoparticles in air. A SiC nanoparticle ink including polyvinylpyrrolidone and ethylene glycol exhibited intense absorption by SiC nanoparticles at the wavelength of 780 nm. The whole of the sintered film patterns from the surface to the bottom underwent significant oxidation at a scanning speed of 1 mm/s, suggesting that the excessive energy irradiation generated silicon oxides. In contrast, the patterns fabricated by laser scanning at a raster pitch of 30 m at which a sintered area was observed at a scanning speed of 5 mm/s, exhibited no significant difference in oxidation of the raw SiC nanoparticles except for the surfaces from 1.72 m. These results indicate that the irradiation of femtosecond laser pulses generated the sintered SiC patterns without additional atmospheric oxidation of the raw materials because of its low heat accumulation. In additions, the dispersant of polyvinylpyrrolidone and ethylene glycol did not affect the sintering by an X-ray photoelectron spectroscopy. This vacuum-free direct printing technique has the potential for additive manufacturing.

Synthesis of heterostructured SiC and C-SiC nanotubes by ion irradiation-induced changes in crystallinity

Taguchi, Tomitsugu; Yamamoto, Shunya; Kodama, Katsuaki; Asaoka, Hidehito

Carbon, 95, p.279 - 285, 2015/12

https://doi.org/10.1016/j.carbon.2015.08.056

Amorphous SiC nanotubes are successfully synthesized by 340 keV Si ions irradiation of polycrystalline SiC nanotubes for the first time. A polycrystalline/amorphous heterostructure SiC nanotube, in which polycrystalline SiC and amorphous SiC coexist in the same nanotube, is also synthesized by ions irradiation with a mask in front of polycrystalline SiC nanotube. According to electron energy loss spectroscopy evaluation, the plasmon energies of SiC nanotube change rapidly at the interface between polycrystalline and amorphous regions. The volume swelling by amorphization evaluated from the differences of plasmon energies is approximately 5.0%. This result reveals that the further relaxed amorphous SiC nanotubes with higher density can be produced. The graphitic shells in carbon layer of C-SiC nanotube gradually bend to the radial direction of nanotube by the ion irradiation. Since the graphite (002) spots in the selected area electron diffraction pattern are clearly observed even after the ion irradiation, the carbon layer in C-SiC nanotube has certain crystallinity. Moreover, the new multi-walled carbon nanotube with the graphitic shells completely parallel to the radial direction of nanotube is also produced inside the amorphous SiC tubular layer in the case of C-SiC nanotube with large caliber.

High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

Iwamoto, Naoya*; Azarov, A.*; Oshima, Takeshi; Moe, A. M. M.*; Svensson, B. G.*

Journal of Applied Physics, 118(4), p.045705_1 - 045705_8, 2015/07

https://doi.org/10.1063/1.4927040

Radiation hardness of n-type SiC Schottky barrier diodes irradiated with MeV He ion microbeam

Pastuovi, *; Capan, I.*; Cohen, D.*; Forneris, J.*; Iwamoto, Naoya*; Oshima, Takeshi; Siegele, R.*; Hoshino, Norihiro*; Tsuchida, Hidekazu*

Nuclear Instruments and Methods in Physics Research B, 348, p.233 - 239, 2015/04

https://doi.org/10.1016/j.nimb.2014.12.064

Relationship between defects induced by irradiation and reduction of hole concentration in Al-doped 4H-SiC

Matsuura, Hideharu*; Kagamihara, So*; Ito, Yuji*; Oshima, Takeshi; Ito, Hisayoshi

Physica B; Condensed Matter, 376-377, p.342 - 345, 2006/04

https://doi.org/10.1016/j.physb.2005.12.088

no abstracts in English

Defect-engineering in SiC by ion implantation and electron irradiation

Pensl, G.*; Ciobanu, F.*; Frank, T.*; Kirmse, D.*; Krieger, M.*; Reshanov, S.*; Schmid, F.*; Weidner, M.*; Oshima, Takeshi; Ito, Hisayoshi; et al.

Microelectronic Engineering, 83(1), p.146 - 149, 2006/01

https://doi.org/10.1016/j.mee.2005.10.040

no abstracts in English

Shallow P donors in 3-, 4-, and 6-SiC

Isoya, Junichi*; Katagiri, Masayuki*; Umeda, Takahide*; Son, N. T.*; Henry, A.*; Gali, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Janzn, E.*

Materials Science Forum, 527-529, p.593 - 596, 2006/00

no abstracts in English

Characterization of charge generated in silicon carbide np diodes using transient ion beam-induced current

Oshima, Takeshi; Sato, Takahiro; Oikawa, Masakazu*; Yamakawa, Takeshi; Onoda, Shinobu; Wakasa, Takeshi; Laird, J. S.; Hirao, Toshio; Kamiya, Tomihiro; Ito, Hisayoshi; et al.

Nuclear Instruments and Methods in Physics Research A, 541(1-2), p.236 - 240, 2005/04

https://doi.org/10.1016/j.nima.2005.01.062

In order to develop particle detectors based on SiC semiconductor, SiC pn-diodes were irradiated with microbeam of 15MeV oxygen ions. The transient current was measured using the single ion hit transient ion beam induced current (TIBIC) system at TIARA. As the results, peak intensity of transient current induded by ion irradiation increased and falltime decreased with increasing applied bias. By the integration of transient current, the charge collection was estimated. It was found that charges generated in deeper region beyond the depletion layer can be collected by the funneling effect.

Effect of thick SiC interphase layers on microstructure, mechanical and thermal properties of reaction-bonded SiC/SiC composites

Taguchi, Tomitsugu; Igawa, Naoki; Yamada, Reiji; Jitsukawa, Shiro

Journal of Physics and Chemistry of Solids, 66(2-4), p.576 - 580, 2005/02

https://doi.org/10.1016/j.jpcs.2004.06.034

SiC/SiC composites are expected to be one of the candidate materials for fusion reactors because of the low radioactivity after neutron irradiation and excellent mechanical properties at high temperature. Reaction-Bonding (RB) process was employed since this process has a possibility of producing a much denser matrix compared with other processes. SiC fibers, however, adhere strongly to the matrix because of high reactiveness of molten Si with the SiC fiber during RB process. In this study, we investigated the effects of SiC layer as an interphase on fracture behavior in the SiC/SiC. The specimen without an interphase layer showed catastrophic failure behavior while the specimen with SiC interphase layer exhibited non-catastrophic failure behavior by 3-point bending testing. The microstructure observation indicated that SiC fibers did not adhere to the matrix in the specimen with SiC interpahse layer. After 3-point bending testing, the pull-out phenomenon occurred in the SiC/SiC with SiC interphase layer while did not occur in the composite without interphase layer.

Negative-U-centers in 4H- and 6H-SiC detected by spectral light excitation

Weidner, M.*; Pensl, G.*; Nagasawa, Hiroyuki*; Schner, A.*; Oshima, Takeshi

Materials Science Forum, 457-460, p.485 - 488, 2004/10

no abstracts in English