A Tech Jewel: Converting Graphene into Diamond Film
martyb writes:
A Tech Jewel: Converting Graphene Into Diamond Film:
Can two layers of the "king of the wonder materials," i.e. graphene, be linked and converted to the thinnest diamond-like material, the "king of the crystals"? Researchers of the Center for Multidimensional Carbon Materials (CMCM) within the Institute for Basic Science (IBS, South Korea) have reported in Nature Nanotechnology the first experimental observation of a chemically induced conversion of large-area bilayer graphene to the thinnest possible diamond-like material, under moderate pressure and temperature conditions. This flexible, strong material is a wide-band gap semiconductor, and thus has potential for industrial applications in nano-optics, nanoelectronics, and can serve as a promising platform for micro- and nano-electromechanical systems.
Diamond, pencil lead, and graphene are made by the same building blocks: carbon atoms (C). Yet, it is the bonds' configuration between these atoms that makes all the difference. In a diamond, the carbon atoms are strongly bonded in all directions and create an extremely hard material with extraordinary electrical, thermal, optical and chemical properties. In pencil lead, carbon atoms are arranged as a pile of sheets and each sheet is graphene. Strong carbon-carbon (C-C) bonds make up graphene, but weak bonds between the sheets are easily broken and in part explain why the pencil lead is soft. Creating interlayer bonding between graphene layers forms a 2D material, similar to thin diamond films, known as diamane, with many superior characteristics.
[...] The team devised a new strategy to promote the formation of diamane, by exposing bilayer graphene to fluorine (F), instead of hydrogen. They used vapors of xenon difluoride (XeF2) as the source of F, and no high pressure was needed. The result is an ultra-thin diamond-like material, namely fluorinated diamond monolayer: F-diamane, with interlayer bonds and F outside.
[...] "This simple fluorination method works at near-room temperature and under low pressure without the use of plasma or any gas activation mechanisms, hence reduces the possibility of creating defects," points out Pavel V. Bakharev, the first author and co-corresponding author.
Journal Reference:
Pavel V. Bakharev, et. al. Chemically induced transformation of chemical vapour deposition grown bilayer graphene into fluorinated single-layer diamond. Nature Nanotechnology, 2019; DOI: 10.1038/s41565-019-0582-z
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