実験番号：202002029（6 シフト）

BL8S1

Crystal structure analysis of nano graphene with XRD
Swapnil Ghodke1，Dennis Christy1, Shih-Nan Hsiao1, Ngo Van Nong1, Osamu Oda1, Masaru Hori1
1
Center for Low temperature plasma sciences (cLPS), Nagoya University
Keyword：Carbon nanowalls，chemical vapour deposition，crystal structure，grazing angle insident
diffraction
1．Background and research purpose
Recently, two-dimentinal graphene sheets which are self-organized graphite nano-structures have attracted greatinterest in the next-generation electrocnic devices [1-2]. Canbon nanowallls (CNW) is a unique structure in whichstacking of few graphene sheets with high preferential orientation stands verlically on the substrate. These sheets
forms a self-supported network with wall thickness ranging from few nanometeres to few tens of nanometers. Its
high aspect ratio, large surface area and large current carrying capability makes it promisining carbon material forenergy storage, catalyst support material, and various device appilcations. Therefore, it is important to investigate
the crystal structure of CNWs, but it is difficult to evalute such highly orientend and highly porous structure by
conventional or laboratory equipments. Therefore, a high-intensity synchrotron radiation with high-resolution
X-ray diffration is required to mearure and analyze CNW crystal structure.
2．Experiment content
The CNWs were grown on copper coated silicon substrate using Radial Injection Plasma Enhanced Chemical
Vapour Deposition (RI-PECVD) in CH4/H2 plasma. The substrate temperature was 700 ℃ and the gas flow rates
for H2 and CH4 were 50 and 100 sccm, respectively.
Synchrotron x-ray diffraction measurements were carried out on the beamline BL8S1 of the Aichi synchrotron
radiation center, Japan.The wavelength of the x-ray was λ = 1.355 A ° corrosponding to 9.15 KeV. At this beamlinecoaxial ( θ-2θ and grazing incidence angle (GID)) and non-coaxial (inplane 2θχ/φ) XRD measurements wereperformed for CNWs grown on Cu/Si subtrate and Cu foil. The GID and inplane measurement were performed toananlyse the crystal structure of the thin layer (1m) of CNW, which possesses high preferential orientation in thevertical direction.
3．Results and Discussion
The diffraction patterns for in-planemeasurements with glancing angle  (0.05,0.1,0.3, and 0.5) are plotted in Figure 1(a),where a diffraction peak corresponding to the(002) diffraction plane of graphite wasobserved at 22.9. The prominent peak wasobserved at a glancing angle 0.1. The
diffraction from C (002) plane was notobserved with the grazing incidence angle of 1
(Fig. 1(b)). This condition may be very close toout-of- plane measurement condition so that Figure 1 X-ray diffraction patterns of (a) in-plane measurements with glancing angle (0.05, 0.1,0.3, and 0.5) and (b) in-plane measurement ( = 0.1), grazing incidence
only diffraction peaks related to copper could measurement (1), and along with the calculated plots of copper and graphite.
be observed. In the inset (Fig. 1(b)), twoslightly broadened peaks related with C (004) and an overlap of Cu (111) and C (101)/(100) was confirmed. Fromthese experimental results, we got clear insight of CNW crystal structure which has strong preferential orientation.
References
1．M. Hiramatsu, K. Shiji, H. Amano, and M. Hori, Appl. Phys. Lett. 84, 4708 (2004).
2．J. J. Wang, M. Y. Zhu, R. A. Outlaw, X. Zhao, D. M. Manos, B. C. Holloway, and V. P. Mammana, Appl. Phys.
Lett. 85, 1265 (2004).