| Co-Investigator(Kenkyū-buntansha) |
KAMATA Masayuki GL Science Ltd., Head Researcher, 開発部主任研究員
TOHJI Kazuyuki Tohoku University, Graduate School of Engineering, Professor, 工学研究科, 教授 (10175474)
TSUNEKAWA Sin Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (00023218)
JEYADEVAN Balachandran Tohoku University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (80261593)
SUTO Shozo Tohoku University, Graduate School of Science, Professor, 理学研究科, 教授 (40171277)
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| Research Abstract |
Nanometer-scale semiconductor and oxide particles are synthesized by solution methods with flotation, emulsion, or reverse micelle technique. Their physical and chemical properties are analyzed for specific materials functions. Sizes are controlled not only by synthesis conditions but also by making use of liquid chromatography.
Small particles of Fe304 are synthesized in their diameter ranging from 4 to 20 nm. These particles are reacted with surfactants in solution and only smallest size particles of 5 nm are selected by flotation. Their size and shape are sufficiently uniform to form regular arrangement in two-dimension on a substrate. Magnetic measurements at 100 Oe show the blocking temperature of 15 K explained by the anisotropy energy coming form surface spin disorder around the surface.
Small particles of CdSe of size as small as 1.3 nm are produced by reverse micelle technique. Optical measurements show a large quantum-size effect of blue shift to 415 nm as compared with 700 nm of the bulk. Absorption spectra are in good agreement with prediction by the spherical quantum well model with effective mass approximation.
Other samples such as CeO2 and ZnO are also produced and their various photochemical effects such as photo-catalytic reactions are analyzed in terms of their size and shape.
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