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

    Laboratory of Functional Thin Film Materials, Materials and Molecular Sciences
  • 研究キーワード
    Research Keywords

    Pulsed laser deposition
    Epitaxial film growth
    Two-dimensional electron gas
Research Subject
High-quality film growth and device fabrication of functional oxides

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. HAADF-STEM image of a [(SrTiO3)24/(SrTi0.8Nb0.2O3)1]20 superlattice, which exhibits giant thermopower. Fig.2. An electric field application provides an extremely thin (~2 nm) two-dimensional electron gas. Fig.3. Experimental setup of thermopower measurement for field effect transistor structure.

文献 / Publications

Nature Mater. 6, 129 (2007).  Nature Commun. 1, 118 (2010).  Adv. Mater. 24, 740 (2012).  Adv. Mater. 25, 3651 (2013).  Nature Mater. 12, 1057 (2013). 

Adv. Mater. 26, 6701 (2014).  Adv. Funct. Mater. 25, 799 (2015).   Adv. Electron. Mater. 2, 1600044 (2016).   Adv. Sci. 4, 1700696 (2017).   Nature Commun. 9, 2224 (2018).