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Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Advanced Materials 2018
September 04-06, 2018
September 04-06, 2018 | Zürich, Switzerland
21
st
International Conference on
Advanced Materials & Nanotechnology
Synthesis of 2D layered semiconductor GaSe for the application of Terahertz non-destructive
inspection
Yutaka Oyama
Tohoku University, Japan
T
erahertz (THz) wave has both superior characteristics of radio wave and light, in which high permeability for non-polar
materials and efficient reflection from metal surface are principal features. Thus, THz wave reflected from the opaque
coated metal surface can be used for nondestructive testing (NDT). In addition, specific inter molecular vibrations (finger print
spectra) of soft and hard materials are appeared in THz frequency region. We have developed various THz wave generators by
careful control of lattice vibrations in semi conducting GaSe crystals. THz wave has low quantum photon energy, thus it is safe
for human tissues even for radiation. We have established a data base of terahertz permeability characteristics for industrial
materials and successfully constructed non-destructive THz diagnosis of building blocks, polymers, insulated copper cable and
hot-dip galvanized steel sheet, etc. For the efficient THz light sources, two-dimensional (2D) layered GaSe has been attracted
much interest because of its superior crystallographic, optical features and even for spintronics. Layered crystals combine
thin sheets by out-of-plane Vander Waals interactions. For the use of practical applications, mechanical strength needs to be
improved. However, no direct experimental determination has been performed up to now for Vander Waals bonding energy.
In our group, a precise tensile testing machine was constructed for the quantitative determination of the inter layer Vander
Waals bonding force. In this study, low temperature liquid phase growth of GaSe and its characterization are shown with the
improvement of Vander Waals bonding energy by the addition of Te and In. Then, some killer applications of THz wave for the
health evaluation of infrastructures will be shown.
Recent Publications:
1. Tanabe T, Watanabe K, Oyama Y and Seo K (2010) Polarization sensitive THz absorption spectroscopy for the
evaluation of uniaxially deformed ultra-high molecular weight polyethylene. NDT&E International 43:329-333.
2. Hasegawa R, Kimura T, Tanabe T, Nishihara K, Taniyama A and Oyama Y (2018) Analysis of the specific vibration
modes of goethite (α-FeOOH) by terahertz spectroscopy and calculations of the vibration frequencies of a single
molecule using density functional theory. Journal of Biomedical Graphics and Computing 8(1):29-34.
3. Takasuna S, Shiogai J, Matsuzaka S,Kohda M, Oyama Y and Nitta J (2017) Weak anti-localization induced by Rashba
spin-orbit interaction in layered III-VI compound semiconductor GaSe thin films. Physical Review B 96:161303(R).
4. Tanabe T, Zhao S, Sato Y and Oyama Y (2017) Effect of adding Te to layered GaSe crystals to increase the Vander
Waals bonding force. Journal of Applied Physics 122(16):165105.
5. Takahashi S, Hamano T, Nakajima K, Tanabe T and Oyama Y (2014) Observation of damage in insulated copper
cables by THz imaging. NDT&E International 61:75-79.
Yutaka Oyama, Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C3-020