Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/06

  • 研究者氏名
    Researcher Name

    安達正芳 Masayoshi ADACHI
    助教 Assistant Professor
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    金属資源プロセス研究センター 高温材料物理化学研究分野
    Center for Mineral Processing and Metallurgy,  High-temperature Physical Chemistry of Materials
  • 研究キーワード
    Research Keywords

    Crystal growth
    Liquid phase epitaxy
    thermophysical properties of liquid metals
Research Subject
Ga-Al フラックスを用いた単結晶窒化アルミニウムの液相成長
Liquid phase epitaxial growth of single crystalline AlN using Ga-Al solution

研究の背景 Background


AlGaN-based LEDs are expected to have various applications, because the emitting photon energy can be tuned from 3.4 to 6.2 eV by selecting composition ratio of GaN and AlN. As a substrate for AlGaN-based LEDs, AlN is a good candidate because of its wide bandgap and small lattice mismatch with AlGaN. However, fabricating larger diameter bulk AlN crystals at reasonable cost has not been achieved to date.

研究の目標 Outcome


We have developed an original liquid phase epitaxy (LPE) method using Ga-Al flux. In this method, 1.2-㎛-thick AlN can be grown on surface nitrided sapphire substrate at 1573 K for 5 h. Recently, we attempt to grow larger-diameter AlN, moreover, we attempt to clarify the growth mechanism of AlN for this LPE method.

研究図Research Figure

Fig.1. Cross-sectional TEM image of AlN layer on sapphire substrate grown using Ga-Al liquid phase epitaxy. [Appl. Phys. Express, 6, 091001 (2013).] Fig.2. High-resolution TEM image of the interface of the sapphire substrate / nitrided sapphire layer / LPE layer taken along the [11-20] AlN zone axis. [Appl. Phys. Express, 6, 091001 (2013).] Fig.3. Schematic of the polarity inversion model indicating trapped oxygen atoms at the surface of the nitrided sapphire layer. [Phys. Stat. Sol. B, in press, DOI: 10.1002/pssb.201451426.]

文献 / Publications

Phys. Stat. Sol. B, published online, DOI:10.1002/pssb.201700478. Mater. Trans., 58, 509 (2017). Phys. Stat. Sol. B, 252, 743 (2015). Appl. Phys. Express, 6, 091001 (2013). Appl. Phys. Express, 5, 101001 (2012). Phys. Stat. Sol. A, 208, 1494, (2011). J. Mater. Sci., 45, 2002 (2010).