Research Activities

Nano-carbon systems

Using equations given in Neto's article, I calculated the band structure of graphene using Mathematica 6.

Single wall and double wall carbon nanotubes

Figure 1. Photoluminescence from dispersed single wall carbon nanotubes. (From Dr. Toshiya MURAKAMI, Kyoto institute of Technology(Present institution:Mitsubishi Electric))

Figure 2. TEM image of Double wall carbon nanotubes.
This figure has been taken by Ms. Kazuyo MATSUMOTO (Former master student at Kyoto Institute of Technology). I display two new figures, PL maps from homemade SWNT(upper) and DWNT(lower).

These figures will be replaced soon (measured at Shimadzu, Kyoto, Japan). Please check our articles on Double walled carbon nanotubes.

Graphene

In November 2015, our article Spectroscopic characterization of nitrogen- and boron-doped graphene layers has been published in Japanese Journal of Applied Physics.

Figure 3. Optical microscopic image and Raman spectra of graphene obtained by cleavage of HOPG and transffered to SiO₂300nm.(From Dr. KAMOI Susumu at KIT, now at Kyoto Prefectual Technology Center for Small and Medium Enterprises. )

Single Atomic layer of Molybdenum Disulphide

Shown below is a clear image of few atomic layers of MoS₂ taken by a graduate student Mr. Minamino. I will upload results of resonant Raman and PL spectroscopies on this sample soon. We have already reported resonance Raman studies on this sample at Spring Meetings of Japan Sciety of Applied Physics, this year(2015). I have to select the figure among our presentation.

Quite interestingly, Prof. Dr. C. Thomsen who had accepted me as a visiting researcher for his group in 2007 shows a similar picture on his homepage. Since 2014, he is the president of Technische Universität Berlin.

Oxide semiconductor nanocrystals

Figure 5. High Resolution TEM image of ZnO:Co nanorod. By Dr. Hasuike of Kyoto Institute of Technology.
I will upload another SEM image soon. And I would like to thank Shimadzu Corporation, Kyoto, Japan for kindly renting their machines.

BiFeO₃ nano crystals

BiFeO₃(abbreviated to BFO, hereafter) is expected to have both ferroelectricity and ferromagnetism. We name this kind of material multiferroics; it possesses at least two ferroic properties among ferroelectricity, ferromagnetism and ferroelasticity. BFO is one of multiferroics and gathers much attention recently. It is expected that magnetization (polarization) can be controlled by manipulating external electric (magnetic) field in BFO. Thus the property of becoming magnetized in electric fields and (electrically) polarized in magnetic fields is called magnetoelectric effect. Pierre Currie(1897) and Perrier(1922) had proposed the effect and there were some experimental studies on this effect. The effect has explained in the famous text "Electrodynamics of continuous media" by Landau and Lifshitz. We have started to study this interesting material and tried to synthesize BFO nanocrystals. Dr. FUKUMURA Hideo supplied me the HRTEM image.

Nitride semiconductor heterostructure

Underconstruction or have to say the research itself is postponed.

Not so recent topics

From 29.05.2007 to 24.09.2007, I have visited Prof. Dr. C. Thomsen, Institut für Festköper Physik, Technische Universität Berlin, Deutschland. I should like to thank Prof. Thomsen for his hospitality. I would also say thank his group members, in particular, Dr. Maria Machon, Herrn Hagen Telg, Marcel Mohr, Nils Rosenkranz, Mattias Müller and Dr. Janina Maulztsch. ( Sorry for omit several people because there are too many to name.) Thanks to their support and hospitality, I could really enjoy the life and research in Berlin.

Insets are pictures of Herrn Hagen Telg and Mattias Müller. Maria, Hagen, Nils, Mattias, and Marcel,please allow me to show this picture in my homepage.

Acknowlegement

I would like to thank Prof. Harima of KIT for his long period of guidance and collabolation since I was a student. Thanks also go to Professors Itoh and Shinozuka for their supports in Wakayama University. Many thanks also to Profs. TANAKA and HASHIMOTO. Off course collaborators Dr. Toshiya MURAKAMI, research associate Dr. Noriyuki HASUIKE, Dr. Hideo FUKUMURA, Kazuyo MATSUMOTO, Ryoji NAITO, Hiroyuki KATOH, Hiroyuki NAKANO, Takaaki NAKAMURA, Akihiro MINAMI, Hiroaki YAMAMOTO, Hitoshi KAKEHI, Nobuhiko TONARI, Atsuyoshi SUZUKI, and FUKUMOTO are very much appreciated for their contributions.

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