1. Remote Epitaxy of Gallium Nitride through Graphene Assistance - MOCVD

    III−V materials, particularly Gallium Nitride (GaN), are used commercially in our life. High breakdown voltage, high luminous efficiency, and tunable bandgap are advantage of GaN. Based on that, Light emitting diode, Power device are fabricated by GaN. Until now, GaN-based devices have been developed so far, but GaN epitaxy is often limited by the strict need for lattice matching with substrate. This requirement not only determine the crystal quality for device performance, but also limit to its application in various fields. In our laboratory, to expand application with high-quality epitaxy, Remote Epitaxy of GaN with the two-dimensional (2D) graphene has been studied by metal organic chemical vapor deposition (MOCVD).

    Remote Epitaxy is helped by 2D material which cannot completely screen the stronger potential field of substrate, which enables quasi-homoepitaxy as meaning of ‘remote’ despite its presence. The grown single-crystalline films can be released from the substrate covered with 2D graphene due to its weak van der Walls force and open up a new opportunity to application of GaN-based device with flexibility and transferability, especially such as high-integrated flexible LED display.

2. III-Nitride nanowire growth and applications - MBE

Fig. 1. SEM images of GaN nanowires grown by plasma-assisted molecular beam epitaxy.
(a) GaN nanowires grown on silicon substrate. (b) GaN nanowires grown on titanium coated quartz substrate.

    A lattice-matching with substrates is essential for thin-film growth of III-Nitride materials. However, by growing the nanowire structure rather than the thin film, this restriction can be considerably reduced. We are researching on the growth of III-Nitride nanowires and applying them to devices such as light-emitting diodes (LEDs). In detail, we are studying the AlGaN nanowire growth for UV-LED and the growth on the hetero-substrates to combine III-nitride materials with other materials such as quartz.

3. Current project

Development of technology for fabrication of high-quality GaN membrane based on substrate-reusable remote-epitaxy technique

    Sponsor: National Research Foundation of Korea(NRF)
    Project Leader: Hoe-Min Kwak

Development of simultaneous growth and fabrication of group-III-nitride-based red/green/blue LEDs through selective-area stress control

    Sponsor: National Research Foundation of Korea(NRF)
    Project Leader: Jeong-woon Kim