Research Institute for Electronic Science, Hokkaido University


LAST UPDATE 2018/10/26

  • 研究者氏名
    Researcher Name

    太田裕道 Hiromichi OHTA
    教授 Professor
  • 所属
    Professional Affiliation

    Research Institute for Electronic Science, Hokkaido University

    Green Nanotechnology Research Center
  • 研究キーワード
    Research Keywords

    Oxide thermoelectric materials
    Transparent oxide semiconductor devices
    Electric field thermopower modulation
    Solid-state thermal transistors
Research Subject
We develop useful devices using ceramics

研究の背景 Background


Since the electronic structure at the surface and/or interface (several nanometers in thickness) of materials is completely different from the solid interior due to the differences of the work functions and chemical potential, surface and/or interface exhibits a variety of interesting electronic / ionic conductivity. However, electrical properties of functional oxides have not been utilized so far due to the lack of high-quality epitaxial films. High-quality epitaxial films with atomically flat surface, which can be fabricated by ultra-precise film growth technique, are necessary to extract their intrinsic potential.

研究の目標 Outcome


We propose novel material design concept of functional oxides by using high-quality epitaxial films, which enable us to clarify interesting phenomenon at the surface and/or interface. Electron transport properties, especially Seebeck effect, of two-dimensional electron gases in oxide superlattices and field effect transistors have been investigated so far. We are now focusing on ionic conductivity at heterointerfaces to realize all solid-state thin film devices near future.

研究図Research Figure

Fig.1. Solid-state thermal transistors that control the thermal conductivity of strontium cobaltite by redox treatment.

Fig.2. Heat conduction in single-crystals is significantly reduced more than randomly oriented polycrystals.

Fig.3. The columnar oxidation from insulating SrCoO2.5 to metallic SrCoO3−δ occurs along the surface normal direction.

文献 / Publications

Q. Yang, H. Ohta et al., Adv. Funct. Mater. 33, 202214939 (2023); H. Yang, H. Ohta et al., ACS Appl. Electron. Mater. 4, 5081 (2022); X. Zhang, H. Ohta et al., ACS Appl. Mater. Interfaces 14, 33355 (2022); X. Zhang, H. Ohta et al., ACS Appl. Mater. Interfaces 13, 54204 (2021); H.J. Cho, H. Ohta et al., Adv. Mater. Interfaces 2001932 (2021).