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Showing 1–5 of 5 results
Advanced filters: Author: Koki Nozawa Clear advanced filters

  • This study demonstrates that hydrogen plasma treatment effectively passivates acceptor defects and grain boundary traps in high-quality polycrystalline Ge thin films, significantly reducing hole concentration to 4 × 1014 cm−3 while maintaining high hole mobility (170 cm2 V−1 s−1). These findings represent the best combination of low carrier concentration and high mobility in polycrystalline Ge, enabling future applications in advanced semiconductor devices.

    • Koki Nozawa
    • Kota Igura
    • Kaoru Toko
    ResearchOpen Access
    NPG Asia Materials
    Volume: 17, P: 1-7

  • Bayesian optimization improved the thermoelectric properties of InGaAsSb thin films; this domain warrants comprehensive investigation due to the need to simultaneously control multiple parameters, such as, the composition, dopant concentration, and film-deposition temperatures. After six optimization cycles, the dimensionless figure of merit exhibited an approximately threefold improvement compared to its values obtained in the random initial experimental trials. These findings not only promote the development of thermoelectric devices based on III–V semiconductors but also highlight the effectiveness of using Bayesian optimization for multicomponent materials.

    • Takamitsu Ishiyama
    • Koki Nozawa
    • Kaoru Toko
    ResearchOpen Access
    NPG Asia Materials
    Volume: 16, P: 1-7