Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/05

  • 研究者氏名
    Researcher Name

    嶋紘平 Kohei SHIMA
    准教授 Associate Professor
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    計測研究部門 量子光エレクトロニクス研究分野
    Division of Measurements, Quantum Optoelectronics
  • 研究キーワード
    Research Keywords

    Optoelectronic devices
    Wide bandgap semiconductors
    Vapor phase deposition and epitaxy
Research Subject
Development of high-efficiency optoelectronic devices using wide bandgap semiconductors

研究の背景 Background


Laser diodes are widely used as solid-state light sources for data transmitters and optical disks due to highly spatial and temporal coherence of their light waves. However, the laser diodes need inversion of the carrier in light emitting, and thus the threshold current density is relatively high (~a few kA/cm2). Recently, as a new laser source capable of reducing the threshold current density and contributing to further energy saving, polariton laser based on light emitting of exciton-polaritons in a strongly coupled microcavity has attracting a great attention.

研究の目標 Outcome


To realize practical polariton lasers, development of film-growth techniques of high-quality wide bandgap semiconductors including GaN and ZnO is essential. In particular, residual impurities and point defects in the grown films work as nonradiative recombination centers (NRCs), and degrade the efficiency of polariton lasing. This study focuses on developing film-growth techniques including metal-organic vapor phase epitaxy and helicon-wave-excited-plasma sputtering epitaxy to eliminate such NRCs in the films.

研究図Research Figure

Fig.1. Intensity color maps of the angular dispersions of the photoluminescence (PL) spectra (300 K) of ZnO microcavities [1].

Fig.2. PL decay signals (300 K) for the near-band-edge mission of p-type Mg-implanted GaN. PL lifetime as a function of the concentration of nonradiative recombination centers for the p-type Mg-implanted GaN [2].

Fig.3. Cross-sectional cathodoluminescence spectral mapping images of p-GaN prepared by vacancy-guided redistribution of Mg [3].

文献 / Publications

[1] Appl. Phys. Lett, 117 (2020) 071103, [2] Appl. Phys. Lett., 113 (2018) 191901,  [3] Appl. Phys. Lett., 119 (2021) 182106.