Programas de Investigación

URI permanente para esta comunidadhttps://repositorioinvestigare.pucmm.edu.do/handle/20.500.12060/2096

La PUCMM cuenta con seis (6) programas de investigación e innovación que responden a su misión de buscar soluciones científicas a los desafíos que enfrenta el pueblo dominicano y su e​ntorno global.

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Examinando Programas de Investigación por Autor "Paredes, Germercy"

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  • Miniatura
    Ítem
    Carbon nanotubes coated with diamond nanocrystals and silicon carbide by Hot-filament chemical vapor deposition below 200 C substrate temperature
    (ELSEVIER) Piazza, Fabrice; Morell, Gerardo; Beltran-Huarac, Juan C.; Paredes, Germercy; Ahmadi, Majid; Guinel, Maxime J.F.
    Multi-walled carbon nanotubes (MWCNTs) dispersed onto a silicon substrate have been coated with diamond nanocrystals (DNC) and silicon carbide (SiC) from solid carbon and silicon sources exposed to H2 activated by hot filament chemical vapor deposition (HFCVD) at around 190 °C substrate temperature. MWCNT coating by DNC initiates during filament carburization process at 80 °C substrate temperature under conventional HFCVD conditions. The hybrid nanocarbon material was analyzed by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy loss spectroscopy, selected area electron diffraction, X-ray diffraction and Raman spectroscopy. The structure of the MWCNTs is preserved during coating and the smooth DNC/SiC coating is highly conformal. The average grain size is below 10 nm. The growth mechanism of DNC and SiC onto MWCNT surface is discussed.
  • Miniatura
    Ítem
    Low temperature, pressureless sp2 to sp3 transformation of ultrathin, crystalline carbon films
    (ELSEVIER) Piazza, Fabrice; Gough, Kathleen; Monthioux, Marc; Puech, Pascal; Gerber, Iann; Wiens, Richard; Paredes, Germercy; Ozoria, Cristhofer
    Nanosized and crystalline sp3-bonded carbon materials were prepared over large surface areas up to ~33x51 m2 from the exposure of few-layer graphene (FLG) to H radicals produced by the hot-filament process at low temperature (below 325 C) and pressure (50 Torr). Hybrid materials were also obtained from the partial conversion of FLG. sp3-C related peaks from diamond and/or lonsdaleite and/or hybrids of both were detected in UV and visible Raman spectra. C-H bonding was directly detected by Fourier Transform Infrared (FTIR) microscopy over an area of ~150 m2 and one single component attributed to sp3-C-H mode was detected in the C-H stretching band showing that carbon is bonded to one single hydrogen and strongly suggesting that the sp3-C materials obtained are ultrathin films with basal planes hydrogenated. The experimental results are compared to computational predictions and comprehensively discussed. Those materials constitute new synthetic carbon nanoforms after fullerenes, nanodiamonds, carbon nanotubes and graphene. This opens the door to new research in multiple areas for the development of new potential applications and may have wide scientific impact, including for the understanding of extraterrestrial diamond-related structures and polytype formation mechanism(s).