Researchers

Research Activities

Research Areas

• Nanotechnology/Materials , Basic physical chemistry
• Nanotechnology/Materials , Thin-film surfaces and interfaces
• Manufacturing technology (mechanical, electrical/electronic, chemical engineering) , Electric/electronic material engineering

Research Interests

表面・界面物性, 光物性, 光電子分光

Published Papers

1. Machine learning study of surface and bulk compositional features governing Ge-incorporated kesterite solar cell performance
   Sanghun Lee; Shinho Kim; Hitoshi Tampo; Takehiko Nagai; Yangdo Kim
   Materials Today Communications  50  , 114436-114436, Jan. 2026  , Refereed
2. Deep learning ellipsometry: Ultrafast and high-accuracy determination of optical constants, film structures, and bandgaps
   Ryosuke Oka; Yuki Yamamoto; James N. Hilfiker; Takuji Maekawa; Hitoshi Tampo; Takehiko Nagai; Hiroyuki Fujiwara
   Materials Today Communications  48  , 113448-113448, Sep. 2025  , Refereed
3. Characterizing ZnMgO/Sb2Se3 Interface for Solar Cell Applications
   Yonghun Je; Jaeeun Jeon; Hitoshi Tampo; Takehiko Nagai; Shinho Kim; Yangdo Kim
   physica status solidi (RRL) – Rapid Research Letters  19  (2)  , 2400267(1)-2400267(6), 26, Nov. 2024  , Refereed

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Conference Activities & Talks

1. Deconvolution of heat flow of lithium-ion batteries operated at low temperature , Jun Okagaki; Takehiko Nagai; Suguru Ueda; Shun Nishijima; Yohei Kawahara; Tsuyoshi Shibata; Ken Okada; Yoshiyasu Saito , The 23rd International Meeting on Lithium Batteries , 18, Jul. 2026
2. Heating-Rate-Dependent Thermal Behavior of Sulfide-Based All-Solid-State Batteries after Degradation , Jun Okagaki; Takehiko Nagai; Yuki Yamaura; Zyun Siroma; Koji Kawamoto; Hikaru Sano , The 23rd International Meeting on Lithium Batteries , 15, Jul. 2026
3. Characterization of electronic properties of (Ba,Sn)S thin films by UPS and IPES , Takehiko Nagai; Soma Endo; Hitoshi Tampo; Hajime Shibata; Norio Terada; Fumio Kawamura; Hidenobu Murata , Material Research Meeting 2025(MRS-J) , 10, Dec. 2025

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MISC

1. Characterization of Electronic Structure in (Ba,Sn)S Thin Film Using XANES , Takehiko Nagai; Hidenobu Murata; Hitoshi Tampo; Fumio Kawamura , UVSOR ACTIVITY REPORT 2023 , 50 , 145 , 2024
2. Excitons and electron-hole plasmas in highly excited GaN , T. Nagai; T. J. Inagaki; Y. Kanemitsu , Physica Status Solidi C: Conferences , 1 , 495 , 498 , Dec. 2020
3. Measurement for Silane Density in Silane-Hydrogen Gas Mixtures Using a Quartz Sensor , SUZUKI Atsushi; KARASAWA Minoru; NAGAI Takehiko; NONAKA Hidehiko; KONDO Michio , Journal of the Vacuum Society of Japan , 53 , 3 , 162 , 164 , 20, Mar. 2010
   Summary:&nbsp;&nbsp;Densities of silane and hydrogen gas mixtures used for the production of thin silicon solar cell were measured using a quartz sensor, which output depends on viscosity and molecular weight of gas measured. The measurement for the silane-hydrogen gas mixtures revealed that the quartz sensor output depends on the silane and hydrogen densitites, can derive each density in the mixtures. From the results of the measurement, working curves were dereived for the pressure of 133-1333.0 Pa for the industrial production at room temperature. Resolusions of the density measured are 0.03 vol.% at total pressure of 1333.0 Pa, and are comparable to the results by a quartz pressure gauge previously reported. Finally, it was shown that the silane density ratio does not agree with the silane flow ratio, indicating that <i>in-situ</i> silane density measurement is important to control silane density.<br>

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Research Grants & Projects

1. Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Development of novel functional semiconductor thin films using high pressure annealing , National Institute for Materials Science
2. 日本学術振興会, 科学研究費助成事業, 有効配位数変調による半導体バンド構造の新しい制御軸構築 , 国立研究開発法人産業技術総合研究所
3. 日本学術振興会, 科学研究費助成事業, 多元系エピタキシャル半導体薄膜を用いた多様な欠陥の評価と制御 , 国立研究開発法人産業技術総合研究所