Organic conducting and semiconducting materials are promising as thermoelectric conversion materials in flexible and wearable electronics because they have large Seebeck coefficients and small thermal conductivities. Since there have been only a limited number of studies on the thermoelectricity of organic materials to date, precise evaluation of Seebeck coefficient and electrical conductivity of various organic conducting/semiconducting thin films is important to examine what kind of material is the most effectual. To carry out such experiments, a specially designed instrument for organic thin films has been developed. Its ability to measure Seebeck coefficients of highly resistive materials was confirmed and Seebeck coefficients and power factors of several typical organic functional materials were preliminary evaluated.

We synthesized a methanol electrocatalyst with high activity and low noble metal content. The electrocatalyst consists of carbon&supported PtRu nanoparticles, which have 1-2 Pt monoatomic layers on Ru nanocores. In spite of the pure Pt surface, the catalyst showed high catalytic activity when used in the anode of a direct methanol fuel cell. Clearly the underlying Ru atoms modified the property of the surface Pt atoms, bringing about the high catalytic activity.

We have investigated the conductivity variation of copper phthalocyanine nano-crystals deposited on SiO2 and mica. The density of surface hydroxyl group on SiO2 was estimated to be more than 10 times larger than that on mica by X-ray photoelectron spectroscopy. The grown crystals on both substrates were categorized to be a-axis orientation of α–form. Conductance-distance (G-d) measurements for various crystalline grains having different heights have been carried out with current imaging using atomic force microscope. The obtained conductivity vs. crystal height plot indicates that lower height crystals have higher conductivities on both surfaces. Besides, the lower height crystals on SiO2 have higher conductivity than those on mica. These results suggest that the electrons in the bottommost molecular layer are transferred to the electrophilic functional groups on the substrate surface. Such a phenomenon at organic semiconductor/insulator interface is reported for the first time.

InN films were grown on Si (111) substrates by radio-frequency plasma-excited molecular beam epitaxy. InN films highly oriented to the c-axis were obtained by optimizing growth conditions in the direct growth on Si. Growth of single crystalline InN films was realized on Si substrates with substrate nitridation for 3 min. On the other hands, when the substrate nitridation was lasted over 30 min, obtained InN films were polycrystalline due to the amorphous SiNx layer formed on a substrate surface. We also studied the local atomic structure in the single crystalline InN film using extended X-ray absorption fine structure measurements.

We have investigated the conductivity variation of copper phthalocyanine nano-crystals deposited on SiO2 and mica. The density of surface hydroxyl group on SiO2 was estimated to be more than 10 times larger than that on mica by X-ray photoelectron spectroscopy. The grown crystals on both substrates were categorized to be a-axis orientation of α–form. Conductance-distance (G-d) measurements for various crystalline grains having different heights have been carried out with current imaging using atomic force microscope. The obtained conductivity vs. crystal height plot indicates that lower height crystals have higher conductivities on both surfaces. Besides, the lower height crystals on SiO2 have higher conductivity than those on mica. These results suggest that the electrons in the bottommost molecular layer are transferred to the electrophilic functional groups on the substrate surface. Such a phenomenon at organic semiconductor/insulator interface is reported for the first time.

High-energy (400 keV) implantation of carbon (C) ions was made into LEC-GaAs substrates with C concentration ([C]) of 1019− 1022Cm−3. 2 K photoluminescence (PL) and Hall effect measurements indicated that activation rate of C in LEC GaAs is both optically and electrically extremely low even after furnace-annealing at 850 °C for 20 min. For [C] = 1×1022 cm−3, two novel strong emissions were obtained and PL measurements as a function of excitation power and sample temperature suggested that the two emissions one at 1.485 eV and the other at 1.305 eV should reflect the formation of a new alloy between GaAs and C. Dual implantation of C+ and Ga+ ions was carried out to improve the activation or substitution rate. We found that nearly 90% activation rate can be achieved for C dose of 2.2 × 1013 cm−2.

Fullerene C60 thin solid films have been fabricated on the (001) surfaces of alkali halides (NaCl, KCI and KBr) and muscovite by organic molecular beam deposition (OMBD) technique. Pure C60 powder was sublimated from the precisely temperature-controlled K-cell at low pressure (10−7 Torr) and deposited onto the substrates kept in the range 125 –300 °C. Increasing both the temperature of K-cell and the substrate temperature, fine crystals grow with different size, shape and distance between neighbors. The dependence of the size and density of island crystals on the deposition conditions revealed the mechanism of crystal growth and the effect of interaction between molecules and substrate surface.