Explorations on Growth of Blue-Green-Yellow-Red InGaN Quantum Dots by Plasma-Assisted Molecular Beam Epitaxy
Xue Zhang,
Zhiwei Xing,
Wenxian Yang,
Haibing Qiu,
Ying Gu,
Yuta Suzuki,
Sakuya Kaneko,
Yuki Matsuda,
Shinji Izumi,
Yuichi Nakamura,
Yong Cai,
Lifeng Bian,
Shulong Lu,
Atsushi Tackeuchi
Affiliations
Xue Zhang
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China
Zhiwei Xing
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China
Wenxian Yang
Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
Haibing Qiu
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China
Ying Gu
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China
Yuta Suzuki
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Sakuya Kaneko
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Yuki Matsuda
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Shinji Izumi
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Yuichi Nakamura
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Yong Cai
Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
Lifeng Bian
Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
Shulong Lu
Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
Atsushi Tackeuchi
Department of Applied Physics, Waseda University, Tokyo 169-8555, Japan
Self-assembled growth of blue-green-yellow-red InGaN quantum dots (QDs) on GaN templates using plasma-assisted molecular beam epitaxy were investigated. We concluded that growth conditions, including small N2 flow and high growth temperature are beneficial to the formation of InGaN QDs and improve the crystal quality. The lower In/Ga flux ratio and lower growth temperature are favorable for the formation of QDs of long emission wavelength. Moreover, the nitrogen modulation epitaxy method can extend the wavelength of QDs from green to red. As a result, visible light emissions from 460 nm to 622 nm have been achieved. Furthermore, a 505 nm green light-emitting diode (LED) based on InGaN/GaN MQDs was prepared. The LED has a low external quantum efficiency of 0.14% and shows an efficiency droop with increasing injection current. However, electroluminescence spectra exhibited a strong wavelength stability, with a negligible shift of less than 1.0 nm as injection current density increased from 8 A/cm2 to 160 A/cm2, owing to the screening of polarization-related electric field in QDs.
