Low temperature, pressureless sp² to sp³ transformation of ultrathin, crystalline carbon films

Fabrice Piazza1*, Kathleen Gough2, Marc Monthioux3, Pascal Puech3, Iann Gerber4, Richard Wiens2, Germercy Paredes1, Cristhofer Ozoria1

1 Nanoscience Research Laboratory, Pontificia Universidad Católica Madre y Maestra, Autopista Duarte km 1 1/2, Apartado Postal 822, Santiago, Dominican Republic
2 Department of Chemistry, Universidad de Manitoba, Winnipeg, Canada
3 Centre d’Elaboration des Matériaux et d’Etudes Structurales (CEMES), CNRS, Université de Toulouse, France
4 Laboratoire de Physico-Chimie des Nano-Objets (LPCNO), CNRS, INSA, Université de Toulouse, France
*Corresponding author. E-mail: fpiazza75@gmail.com; fpiazza@pucmm.edu.do (Fabrice Piazza)

ABSTRACT: Nanosized and crystalline sp³-bonded carbon materials were prepared over large surface areas up to ~33×51 μm² 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 μm² 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).

Low temperature, pressureless sp² to sp³ transformation of ultrathin, crystalline carbon films