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IR transmittance of large-sized free-standing transparent diamond films prepared by MWPCVD
352 a
CARBON
4 7 ( 2 0 0 9 ) 3 5 0 –3 5 4
Shanghai Institute of Applied Physics, Chinese Academy of Sciences,
a
State Key Laboratory of Superhard Materials, Jilin University,
Shanghai 201800, China
Changchun 130012, China
b
b
Graduate School of the Chinese Academy of Sciences, Beijing 100049,
China
College of Electrical and Electronic Engineering, Harbin University of
Science and Technology, Harbin 150040, China
Nano-graphite (NG) deposits were formed on multi-walled carbon nanotubes (MWCNTs) lying on a single-crystal-silicon plane by irradiating them with an 80 eV ion beam perpendicular to the plane. The ion beam was produced using a methane and hydrogen mixture (1:5) at 700 °C. Electron microscopy indicates that there is an angle in the range 45°–90° between the (0 0 0 2) planes of the formed NG particles and the axis of the MWCNTs. The MWCNTs retained their inner hollow structure. The formation of the NGs can be ascribed to the high temperature decomposition and deposition of methane, and the observation of specific angles (45°–90°) between the (0 0 0 2) planes of the NGs and the MWCNT axis may be attributed to the selective etching, or removal, by the hydrogen ions of NG nuclei with 0°–45° between their (0 0 0 2) planes and the MWCNT axis.
Large-sized free-standing transparent diamond films of 50 mm diameter and 300 lm thickness were prepared by microwave plasma chemical vapor deposition (MWPCVD). The growth rate of the diamond film was only 1–2 lm/h when the diamond film was grown at a methane concentration of 2%, and the infrared (IR) transmittance reached 70% in the range of 500–4000 cm
1
after the film was polished on both sides. A high growth rate of 7– 8 lm/h was achieved for the film grown at a methane concentration of 4%. The thickness of the film was 260 lm after it was polished on both sides and its IR transmittance in the range of 500– 4000 cm
1
reached about 60%. Meanwhile, the IR transmittance
was almost the same in the central and fringe regions. These results imply a promising application of large-sized thick diamond films in IR windows.
[New Carbon Materials 2008;23(3):235–40.]
[New Carbon Materials 2008;23(3):245–9.]
doi:10.1016/j.carbon.2008.09.019 doi:10.1016/j.carbon.2008.09.021
The role of a graphitic surface layer in electron-stimulated Simultaneous formation of silicon carbide and diamond on Si
ordering in tetrahedral amorphous carbon films Shi-jin
Liang a, Tatsuya Banno a, Yutaka Mera a, Masahiro
Kitajima b,
Kunie
Ishioka b,
Yoshihisa
Harada c,
Yoshinori
Kitajima d, Shik Shin c,e, Koji Maeda a a
Department of Applied Physics, The University of Tokyo, Hongo,
substrates by microwave plasma assisted chemical vapor deposition Chun-Jiu Tang a,b, Lian-She Fu c, A.J.S. Fernandes b, M.J. Soares b, Gil Cabral a, A.J. Neves b, J. Gra´cio a
Bunkyo-ku, Tokyo 113-8656, Japan
a
b
Mechanical Engineering, University of Aveiro, Aveiro 3810-193, Portugal
National Institutes for Materials Science (NIMS), Tsukuba, Ibaraki
Center for Mechanical Technology and Automation and Department of
305-0047, Japan
b
Department of Physics, University of Aveiro, Aveiro 3810-193, Portugal
c
RIKEN/SPring-8, Sayo-gun, Hyogo 679-5198, Japan
c
Department of Physics and CICECO, University of Aveiro, Aveiro
d
Photon Factory, Institute of Materials Structure Science, High Energy
3810-193, Portugal
Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan e
Institute for Solid State Physics, The University of Tokyo, Kashiwa,
Chiba 277-8581, Japan Electron-stimulated graphitic ordering in tetrahedral amorphous carbon (ta-C) films was found to be affected by the removal of the graphitic surface layer present in as-deposited films. To remove the graphitic layer on ta-C films fabricated by the filtered cathodic vacuum arc method, the sample was etched with oxygen plasma. The removal of the surface layer was examined by transmission electron energy loss spectroscopy, surface-enhanced Raman spectroscopy, and surface-sensitive X-ray absorption spectroscopic measurements. The electron-stimulated graphitization was retarded in oxygen plasma etched samples presumably owing to the lack of graphitic nuclei for heterogeneous nucleation. [New Carbon Materials 2008;23(3):241–4.] doi:10.1016/j.carbon.2008.09.020
The effects of several process parameters, such as substrate temperature, nucleation density, and substrate surface pretreatment, on the simultaneous formation of SiC and diamond under typical growth conditions of diamond by microwave plasma assisted chemical vapor deposition (MPCVD), have been investigated by scanning electron microscopy (SEM), X-ray diffraction, and Raman and Fourier-transfer infrared (FT-IR) spectroscopy. Results show that no SiC can be detected in the diamond films grown with a high nucleation density, whereas, SiC is detected in the thick diamond films grown with a low nucleation density, with or without surface pretreatment of the Si substrates. SEM micrographs and FT-IR spectra illustrate that SiC is formed on the Si substrate not covered by diamond nuclei or in void regions between diamond nuclei. The formation of SiC and diamond on Si substrates under the growth conditions of diamond by MPCVD is a concurrent competitive deposition process, especially at the initial stage of diamond nucleation and growth. This is an alternative method for the synthesis of diamond-SiC composites by MPCVD. [New Carbon Materials 2008;23(3):250–8.]
IR transmittance of large-sized free-standing transparent diamond films prepared by MWPCVD Bo Li a, Bai Han b, Xian-Yi Lu a, Hong-Dong Li a, Jian-Bo Wang a, Zeng-Sun Jin a
doi:10.1016/j.carbon.2008.09.022
CARBON
4 7 ( 2 0 0 9 ) 3 5 0 –3 5 4
Shanghai Institute of Applied Physics, Chinese Academy of Sciences,
a
State Key Laboratory of Superhard Materials, Jilin University,
Shanghai 201800, China
Changchun 130012, China
b
b
Graduate School of the Chinese Academy of Sciences, Beijing 100049,
China
College of Electrical and Electronic Engineering, Harbin University of
Science and Technology, Harbin 150040, China
Nano-graphite (NG) deposits were formed on multi-walled carbon nanotubes (MWCNTs) lying on a single-crystal-silicon plane by irradiating them with an 80 eV ion beam perpendicular to the plane. The ion beam was produced using a methane and hydrogen mixture (1:5) at 700 °C. Electron microscopy indicates that there is an angle in the range 45°–90° between the (0 0 0 2) planes of the formed NG particles and the axis of the MWCNTs. The MWCNTs retained their inner hollow structure. The formation of the NGs can be ascribed to the high temperature decomposition and deposition of methane, and the observation of specific angles (45°–90°) between the (0 0 0 2) planes of the NGs and the MWCNT axis may be attributed to the selective etching, or removal, by the hydrogen ions of NG nuclei with 0°–45° between their (0 0 0 2) planes and the MWCNT axis.
Large-sized free-standing transparent diamond films of 50 mm diameter and 300 lm thickness were prepared by microwave plasma chemical vapor deposition (MWPCVD). The growth rate of the diamond film was only 1–2 lm/h when the diamond film was grown at a methane concentration of 2%, and the infrared (IR) transmittance reached 70% in the range of 500–4000 cm
1
after the film was polished on both sides. A high growth rate of 7– 8 lm/h was achieved for the film grown at a methane concentration of 4%. The thickness of the film was 260 lm after it was polished on both sides and its IR transmittance in the range of 500– 4000 cm
1
reached about 60%. Meanwhile, the IR transmittance
was almost the same in the central and fringe regions. These results imply a promising application of large-sized thick diamond films in IR windows.
[New Carbon Materials 2008;23(3):235–40.]
[New Carbon Materials 2008;23(3):245–9.]
doi:10.1016/j.carbon.2008.09.019 doi:10.1016/j.carbon.2008.09.021
The role of a graphitic surface layer in electron-stimulated Simultaneous formation of silicon carbide and diamond on Si
ordering in tetrahedral amorphous carbon films Shi-jin
Liang a, Tatsuya Banno a, Yutaka Mera a, Masahiro
Kitajima b,
Kunie
Ishioka b,
Yoshihisa
Harada c,
Yoshinori
Kitajima d, Shik Shin c,e, Koji Maeda a a
Department of Applied Physics, The University of Tokyo, Hongo,
substrates by microwave plasma assisted chemical vapor deposition Chun-Jiu Tang a,b, Lian-She Fu c, A.J.S. Fernandes b, M.J. Soares b, Gil Cabral a, A.J. Neves b, J. Gra´cio a
Bunkyo-ku, Tokyo 113-8656, Japan
a
b
Mechanical Engineering, University of Aveiro, Aveiro 3810-193, Portugal
National Institutes for Materials Science (NIMS), Tsukuba, Ibaraki
Center for Mechanical Technology and Automation and Department of
305-0047, Japan
b
Department of Physics, University of Aveiro, Aveiro 3810-193, Portugal
c
RIKEN/SPring-8, Sayo-gun, Hyogo 679-5198, Japan
c
Department of Physics and CICECO, University of Aveiro, Aveiro
d
Photon Factory, Institute of Materials Structure Science, High Energy
3810-193, Portugal
Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan e
Institute for Solid State Physics, The University of Tokyo, Kashiwa,
Chiba 277-8581, Japan Electron-stimulated graphitic ordering in tetrahedral amorphous carbon (ta-C) films was found to be affected by the removal of the graphitic surface layer present in as-deposited films. To remove the graphitic layer on ta-C films fabricated by the filtered cathodic vacuum arc method, the sample was etched with oxygen plasma. The removal of the surface layer was examined by transmission electron energy loss spectroscopy, surface-enhanced Raman spectroscopy, and surface-sensitive X-ray absorption spectroscopic measurements. The electron-stimulated graphitization was retarded in oxygen plasma etched samples presumably owing to the lack of graphitic nuclei for heterogeneous nucleation. [New Carbon Materials 2008;23(3):241–4.] doi:10.1016/j.carbon.2008.09.020
The effects of several process parameters, such as substrate temperature, nucleation density, and substrate surface pretreatment, on the simultaneous formation of SiC and diamond under typical growth conditions of diamond by microwave plasma assisted chemical vapor deposition (MPCVD), have been investigated by scanning electron microscopy (SEM), X-ray diffraction, and Raman and Fourier-transfer infrared (FT-IR) spectroscopy. Results show that no SiC can be detected in the diamond films grown with a high nucleation density, whereas, SiC is detected in the thick diamond films grown with a low nucleation density, with or without surface pretreatment of the Si substrates. SEM micrographs and FT-IR spectra illustrate that SiC is formed on the Si substrate not covered by diamond nuclei or in void regions between diamond nuclei. The formation of SiC and diamond on Si substrates under the growth conditions of diamond by MPCVD is a concurrent competitive deposition process, especially at the initial stage of diamond nucleation and growth. This is an alternative method for the synthesis of diamond-SiC composites by MPCVD. [New Carbon Materials 2008;23(3):250–8.]
IR transmittance of large-sized free-standing transparent diamond films prepared by MWPCVD Bo Li a, Bai Han b, Xian-Yi Lu a, Hong-Dong Li a, Jian-Bo Wang a, Zeng-Sun Jin a
doi:10.1016/j.carbon.2008.09.022