Metal-catalyzed chemical vapor deposition (CVD) has been broadly employed for large-scale production of high-quality graphene. However, a following transfer process to targeted substrates is needed, which is incompatible with current silicon technology. We here report a new CVD approach to form nanographene and nanographite films with accurate thickness control directly on non-catalytic substrates such as silicon dioxide and quartz at 800 °C. The growth time is as short as a few seconds. The approach includes using 9-bis(diethylamino)silylanthracene as the carbon source and an atomic layer deposition (ALD) controlling system. The structure of the formed nanographene and nanographite films were characterized using atomic force microscopy, high resolution transmission electron microscopy, Raman scattering, and x-ray photoemission spectroscopy. The nanographite film exhibits a transmittance higher than 80% at 550 nm and a sheet electrical resistance of 2000 ohms per square at room temperature. A negative temperature-dependence of the resistance of the nanographite film is also observed. Moreover, the thickness of the films can be precisely controlled via the deposition cycles using an ALD system, which promotes great application potential for optoelectronic and thermoelectronic-devices.
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http://dx.doi.org/10.1088/1361-6528/aab4c1 | DOI Listing |
Nanotechnology
May 2018
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yutian Road, 200083 Shanghai, People's Republic of China. University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
Metal-catalyzed chemical vapor deposition (CVD) has been broadly employed for large-scale production of high-quality graphene. However, a following transfer process to targeted substrates is needed, which is incompatible with current silicon technology. We here report a new CVD approach to form nanographene and nanographite films with accurate thickness control directly on non-catalytic substrates such as silicon dioxide and quartz at 800 °C.
View Article and Find Full Text PDFPhys Chem Chem Phys
October 2017
Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences, 159, Prospekt 100-letiya, 690022 Vladivostok, Russia.
The existence of zero-energy edge π-electronic states (zero modes) in turbostratic few-layer nanographenes (nanographites) has been established and the sensitivity of their characteristics to the presence of adsorbed chlorine molecules and covalent bonds of halogen with dangling edge carbon orbitals has been studied using a combination of wide- and small-angle X-ray diffraction, Raman spectroscopy, XPS, EPR and magnetic susceptibility experiments. The reversible change in density of the edge π-electronic states found under the influence of an adsorbate has been explained by their spin-splitting initiated with the transfer of a small part of the electron density from the nanographites to the adsorbate. The change of the sign of the temperature coefficient of the current carrier spin relaxation rate caused by the adsorbate has also been accounted for in the framework of this model as a consequence of interaction of mobile spins with edge spin-split (magnetically ordered) states.
View Article and Find Full Text PDFJ Phys Chem Lett
February 2012
Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.
Graphene has become a primary material in nanotechnology and has a wide range of potential applications in electronics. Fabricated graphenes are generally nanosized and composed of stacked graphene layers. The edges of nanographenes predominantly influence the chemical and physical properties because nanographene layers have a large number of edges.
View Article and Find Full Text PDFDalton Trans
August 2008
Department of Chemistry, Tokyo Institute of Technology, 2-12-1/W4-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
Nanographene has a unique electronic structure which critically depends on the shape of its edge. A zigzag-edged nanographene sheet has a non-bonding pi-electron state (edge state), yielding a strong spin magnetism for edge-state localized spins, in spite of the absence of such a state in an armchair-edged nanographene sheet. Nanographite (stacked nanographene sheets)-network-based nanoporous carbon is employed as the host material to build unconventional magnetic systems based on the host-guest interaction.
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