Catalyst-Free Growth of Networked Nanographite on Si and SiO2 Substrates by Photoemission-Assisted Plasma-Enhanced Chemical Vapor Deposition

Tomohide Takami; Shuichi Ogawa; Haruki Sumi; Toshiteru Kaga; Akihiko Saikubo; Eiji Ikenaga; Motonobu Sato; Mizuhisa Nihei; Yuji Takakuwa

doi:10.1380/ejssnt.2009.882

Regular Papers

Catalyst-Free Growth of Networked Nanographite on Si and SiO₂ Substrates by Photoemission-Assisted Plasma-Enhanced Chemical Vapor Deposition

Tomohide Takami, Shuichi Ogawa, Haruki Sumi, Toshiteru Kaga, Akihiko Saikubo, Eiji Ikenaga, Motonobu Sato, Mizuhisa Nihei, Yuji Takakuwa

Author information

Tomohide Takami
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan
Shuichi Ogawa
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan
Haruki Sumi
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan
Toshiteru Kaga
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan
Akihiko Saikubo
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Japan Synchrotron Radiation Research Institute, Japan
Eiji Ikenaga
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Japan Synchrotron Radiation Research Institute, Japan
Motonobu Sato
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Fujitsu Limited, Japan
Mizuhisa Nihei
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Fujitsu Limited, Japan
Yuji Takakuwa
Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, Japan
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan

Keywords: Multilayer graphene, CVD, Catalyst-free, Xe excimer lamp, Photoemission, DC discharge plasma, TEM, Raman spectroscopy, XPS, Synchrotron radiation

JOURNAL FREE ACCESS

2009 Volume 7 Pages 882-890

DOI https://doi.org/10.1380/ejssnt.2009.882

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Abstract

We have developed a photoemission-assisted plasma-enhanced chemical vapor deposition (CVD) process, where DC discharge plasma is assisted by photoelectrons emitted from the substrate under ultraviolet (UV) light irradiation. Under Ar gas atmosphere and in vacuum, plasma current was measured as a function of sample bias voltage to clarify the mechanism, by which photoemission-assisted plasma is generated. Owing to the advantages of the photoemission-assisted plasma-enhanced CVD, where the plasma is generated close to the substrate and in a controllable volume, we have succeeded in growing shiny black films of networked nanographite, without any catalyst, on Si(001) and SiO₂(350 nm)/Si(001) substrates at a deposition rate of ∼2 μm/min despite of low electric power consumption of plasma, ∼4 W. Cross-sectional transmission electron microscopy (TEM) and diffraction (TED) observations revealed that samples grown at ∼700°C with Ar-diluted CH₄ were composed of multilayer graphene particles (diameter of ∼10 nm) that were closely connected to each other and shared some graphene sheets between them, although their crystallographic configurations were randomly oriented. In bulk-sensitive C 1s photoelectron spectra using synchrotron radiation at 7933 eV, a chemically-shifted component of sp²-bonded carbon atom was dominant and the π—π^* transition loss peak was clearly observed for the samples grown on both substrates, indicating that the multilayer graphene particles substantially contain high-quality graphene sheets in agreement with evaluations by microscopic Raman spectroscopy. We named the layered carbon structure “carbon mille-feuille.” [DOI: 10.1380/ejssnt.2009.882]

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