2025年9月4日～6日、マレーシア、プトラジャヤにおいて、ICSTE（International Conference on Applied Sciences and Education Technology）2025が開催されました。磯野舞奈さん（大学院2年生）、および、アイナさん（学部4年生、マレーシアからの留学生）は口頭発表を行い、いずれも口頭発表賞を受賞しました。また、小川奈緒子（大学院1年生）はポスター発表を行い、ポスター発表賞を受賞しました。香川大学学生のトリプル受賞となりました。

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The Best Presentation Award,?

Mana Isono^★, Aina Najwa Binti Abdul Nasir^?and Yoshifumi Suzaki:?
"Effect of Mixing Hydrogen Gas into Plasma Gas on the Preparation?of ZnO Transparent Conductive Thin Films?by Atmospheric Pressure Low Temperature Plasma",?

Abstract;?
? ? ?Homogeneous non-equilibrium cold plasma was generated stably using high voltage pulsed power (2.0 kV, 20 kHz) excitation of Ar and O₂ gases under atmospheric pressure. By feeding DPM₂Zn (Bis (2,2,6,6-tetramethyl-3,5-heptanedionato) zinc) into the plasma with Ar carrier gas and mixing H₂ gas into plasma Ar gas, ZnO thin films about 125 nm thick were successfully prepared on glass substrates directly under the slit in an electrode at the substrate temperature of 400℃. In this paper, we describe the effects of H₂ gas mixed into plasma Ar gas on the preparation of ZnO transparent conductive thin films. The average transmittance of the ZnO thin films was over 87% with wavelength ranging from 400 to 800 nm. X-ray diffraction measurements revealed that the ZnO thin films have polycrystalline structure oriented c-axis. When the H₂ gas flow rate increased, the intensity of the X-ray diffraction peaks increased, and the electrical resistivity decreased into 13.3 Ωcm (at 50 ccm). FE-SEM observations of ZnO thin films with the H₂ gas flow rate of 50 ccm showed larger grains and smaller grain boundary gaps compared to the ZnO thin films without H₂ gas. By mixing H₂ gas into plasma Ar gas, hydrogen radicals were generated in the plasma and terminated the dangling bonds at the grain boundaries. The grain boundaries were thereby reduced, and the thin film became a partially continuous microstructure, which is thought to have increased the electron mobility and then decreased the electrical resistivity.

Aina Najwa binti Abdul Nasir^★, Mana Isono?and Yoshifumi Suzaki:?
"ZnO Thin Film Preparation Using Water Vapor Mixing and Atmospheric Pressure Low Temperature Plasma",?

Abstract;?
? ? ?ZnO thin films were fabricated by the generation of non-equilibrium low temperature plasma at atmospheric pressure, which was generated by using high frequency pulse power supply(1.8 kV, 20 kHz). The raw material, DPM₂Zn (Bis (2,2,6,6-tetramethyl-3,5-heptanedionato) zinc) was decomposed by the generated plasma for film fabrication. The first experiment was by fixing the flow rate of Oxygen at 15 ccm and changing the variable flow rate of water vapor from 0 ccm to 1.0 ccm. The average thickness of the film was about 100 nm and the films showed high transparency in wavelengths ranging from 300 nm to 800 nm. The lowest average electrical resistivity obtained was 38.7 Ωcm when water vapor flow rate was 0.8 ccm. The second experiment was by having the constant flow of water vapor at 0.8 ccm while changing the flow rate of Oxygen from 10 ccm to 25 ccm. Transparent ZnO thin films about 105 nm thick were obtained. In this experiment, the results showed that the average electrical resistivity is at its minimum value when Oxygen flow rate was 15 ccm. The average visible light range transmittance obtained was over 90%. A high peak was obtained at the position of (002) plane of the ZnO film. As the oxygen flow rate increases, the orientation to the (002) plane also increases. From these results, it appears that by adding an amount of water vapor into the plasma gas, the electrical resistivity of ZnO thin films can be decreased.?

Naoko Ogawa^★, Raiki Nitta, Naoshi Takahashi, Kazufumi Ogawa and Yoshifumi Suzaki;?
"Development of new silicon film fabrication process using a paste of highly?crystalline silicon nanoparticles covered with chemically adsorbed monolayers",?

Abstract;?
? ? ?We are developing a new silicon film fabrication process using a paste of highly crystalline silicon (Si) nanoparticles covered with chemically adsorbed monolayers (CAM). Our process has advantageous for its potential scalability and cost-effectiveness. In previous studies, only silicon thin films with high electrical resistivity were obtained due to the polymerization of EETS (2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane), a silane-based coupling agent used in CAM formed around Si nanoparticles, due to the use of aqueous solvents. In this study, we examined a method of forming CAM on an n-type silicon substrate by combining a non-aqueous solvent and an acid catalyst as an important pre-experiment to solve this problem. In addition, we added a standard SC1 cleaning process as a pre-treatment to improve the surface condition of the n-type Si substrate. The ellipsometry measurement revealed that the oxide film on the surface of the silicon substrate was reduced by the pretreatment. The decrease in the water droplets contact angle indicates that OH groups on the silicon surface had increased by the pretreatment. The results of FT-IR measurement showed that the formation of CAM was successfully fabricated on the silicon substrate under these combinations. It can be concluded that the development of a new method for fabricating silicon nanoparticles thin films has taken a step forward.?

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