S-Space College of Natural Sciences (자연과학대학) Dept. of Physics and Astronomy (물리·천문학부) Physics (물리학전공) Theses (Master's Degree_물리학전공)
Morphology controlled growth of GaN microstructures on graphene for flexible light emitting diodes
그래핀 위에 형태 조절 가능한 질화갈륨 마이크로 구조물과 유연한 발광소자
- 자연과학대학 물리·천문학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (석사)-- 서울대학교 대학원 자연과학대학 물리·천문학부, 2017. 8. 이규철.
- Recently semiconductor materials have great attention for the achievement of technologies such as graphene and GaN. The graphene got a Nobel Prize at 2010. The graphene is suitable for optoelectronic devices such as optically transparency, flexibility, and mechanically strong. Above all things, the graphene can be easily lift off from substrate because bonding between layers is very week. The GaN materials also got a Nobel Prize at 2014. The GaN materials improve the efficiency of light emitting diodes (LEDs). The GaN has many properties such as high carrier mobility, high recombination rate, and long term stability. Therefore, the growth of GaN LEDs on graphene layers have both advantages of graphene and GaN materials. The combination of GaN materials and graphene will lead to wearable display.
The goal of this research is mainly morphology control of GaN microstructures such as pyramid shape, disk shape, and rod shape on graphene layers. However, it is hard to grow GaN microstructures on graphene layers directly. The buffer layer should grow between the graphene and GaN microstructures. Conventionally the GaN LEDs coated on ZnO nanotube or nanowires, but in this research the GaN micro-rods minimize dependency of the buffer layer. Finally, the high aspect ratio GaN micro-rods are grown on thin ZnO nanowall. To fabricate high quality of LEDs, it is important to control quantum wells. The GaN/InxGa1-xN is coated on GaN micro-rods, which has a large area of p-n junctions. Optical characteristics show the spectrum of blue light.