Article
Optics
Hyun Jeong, Ga Hyun Cho, Mun Seok Jeong
Summary: We propose an efficient method to reduce efficiency droop in InGaN QWs by redistributing carrier localization through thermal annealing, resulting in increased internal quantum efficiency (IQE) in this study.
JOURNAL OF LUMINESCENCE
(2022)
Article
Optics
Longheng Qi, Peian Li, Xu Zhang, Ka Ming Wong, Kei May Lau
Summary: A prototype of full-color micro-LED micro-display with a pixel density of 391 ppi is demonstrated using InGaN/AlGaInP heterogeneous integration. This display shows the feasibility and prospects of high brightness, good color performance, and high-resolution micro-LED micro-displays in future metaverse applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
Shengjun Zhou, Zehong Wan, Yu Lei, Bin Tang, Guoyi Tao, Peng Du, Xiaoyu Zhao
Summary: This study proposes the use of InGaN quantum wells with gradually varying indium content to enhance the performance of GaN-based green LEDs. Experimental results demonstrate that green LEDs with gradually varying indium content exhibit higher light output power and lower efficiency droop.
Article
Chemistry, Physical
Siyuan Cui, Guoyi Tao, Liyan Gong, Xiaoyu Zhao, Shengjun Zhou
Summary: This study reports the development of highly efficient indium gallium nitride (InGaN)-based yellow light-emitting diodes (LEDs) with low efficiency droop. By systematically engineering the indium composition in InGaN quantum barriers (QB), the researchers were able to improve electron confinement and suppress polarization field. This resulted in improved radiative recombination rates and reduced efficiency droop in the yellow LEDs. The study provides a feasible solution for high-performance InGaN-based LEDs in the long-wavelength spectral region.
Article
Physics, Applied
K. H. Li, Y. F. Cheung, W. Y. Fu, H. W. Choi
Summary: The combination of high-quality factors and small mode volumes in whispering-gallery-mode (WGM) resonators promotes significantly enhanced light-matter interactions, making them excellent cavities for achieving compact semiconductor lasers with low threshold and narrow linewidth. The researchers report on WGM emission from vertical-injection blue-light emitting InGaN/GaN thin-film microdisks achieved by wafer bonding and laser liftoff removal of the sapphire substrate, showing high Q-factors. This work presents a viable approach toward the practical implementation of compact InGaN/GaN microdisk lasers through a simple and scalable process.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Kyung Rock Son, Vignesh Murugadoss, Kyeong Heon Kim, Tae Geun Kim
Summary: This study investigates the effect of different passivation materials on the chemical bonds at the sidewall/passivation layer interface of μ-LEDs. The results show that the right passivation material can suppress non-radiative defects and enhance the light output power and current density of μ-LEDs.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Applied
Xiaoyu Zhao, Bin Tang, Liyan Gong, Junchun Bai, Jiafeng Ping, Shengjun Zhou
Summary: Efficient InGaN-based yellow LEDs with optimized three-layer staggered quantum wells exhibit lower forward voltages and narrower full widths at half maximum, as well as higher light output power and external quantum efficiency. Atomic probe tomography and time-resolved photoluminescence confirm the staggered In profile and reduced defect-state carrier trapping in staggered QWs. Furthermore, transmission electron microscopy with energy-dispersive x-ray mapping spectroscopy supports the idea that staggered QWs have uniform elemental distribution and improved crystal quality, contributing to enhanced LED performance.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Jacob J. Ewing, Cheyenne Lynsky, Matthew S. Wong, Feng Wu, Yi Chao Chow, Pavel Shapturenka, Michel Iza, Shuji Nakamura, Steven P. Denbaars, James S. Speck
Summary: This article studied the method of achieving highly efficient long-wavelength InGaN LEDs through V-defect engineering, which utilized naturally occurring V-defects for lateral injection and improved the external quantum efficiency.
Review
Materials Science, Multidisciplinary
Wai Yuen Fu, Hoi Wai Choi
Summary: With the increasing interest in full-color microLED display technologies, researchers have been looking for cost-effective solutions to achieve multicolor emission from a single wafer. Monolithic integration of different color emitters onto a single chip or wafer offers higher yield, scalability, robustness, efficiency, and manufacturability compared to traditional heterogeneous integration approaches. This review provides an overview of the main monolithic integration approaches for polychromatic emitters and highlights the potential applications in phosphor-free white light sources, chip-scale color microLED displays, and GaN-based optoelectronic systems and platforms.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Chemistry, Physical
Do-Yeong Shin, Taehwan Kim, Ozgun Akyuz, Hilmi Volkan Demir, In-Hwan Lee
Summary: This study presents an improved efficiency design for white LEDs by integrating blue nanorod LEDs with green and red-emitting perovskite nanocrystal films. The design utilizes the localized surface plasmon effect of Ag@SiO2 nanoparticles to enhance the photoluminescence intensity of blue LEDs, while the high-power blue LED backlight improves the perovskite photoluminescence intensity. The resulting white LED with Ag@SiO2 nanoparticle-embedded nanorods demonstrates a 62% increase in photoluminescence intensity compared to planar white LEDs.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Optics
Xingfei Zhang, Zhicong Li, Yiyun Zhang, Xuedong Wang, Xiaoyan Yi, Guohong Wang, Jinmin Li
Summary: Heterogeneous integration of nitrides on Si (100) has been achieved by transferring GaN epitaxial layer onto Si (100) using wafer bonding, laser lift-off, and chemical mechanical polishing (CMP) processes. The transferred GaN epilayer has reduced surface roughness and mitigated residual stress. Arrays of microcavities with diverse geometrics and sizes have been fabricated, allowing optically-pumped green lasing. Electrically-injected microdisks with low leakage current and reduced thermal effects have also been successfully fabricated.
Article
Engineering, Electrical & Electronic
Zhe Zhuang, Daisuke Iida, Martin Velazquez-Rizo, Kazuhiro Ohkawa
Summary: Amber InGaN micro-light-emitting diodes were demonstrated with varying peak wavelengths, full-width values, external quantum efficiency, and characteristic temperatures at different current densities. The study showed changes in performance characteristics such as blue shift, increased FWHM, external quantum efficiency, and characteristic temperature with increasing current density, mainly due to the saturation of non-radiative recombination processes.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Physics, Applied
Joonho Back, Vincent Rienzi, Matthew S. Wong, Hongjian Li, Steven P. DenBaars, Claude Weisbuch, Shuji Nakamura
Summary: Blue semipolar InGaN microcavity light-emitting diodes (MC-LEDs) with cavity lengths of 113, 205, and 290 nm were successfully fabricated, showing the potential for ultra-thin MC-LEDs. The peak external quantum efficiencies (EQEs) of these MC-LEDs varied depending on the quantum well (QW) positions within the cavity, with the 290 nm cavity length MC-LED achieving the highest peak EQE of 6.7%. The emission characteristics of the MC-LEDs remained consistent at a peak wavelength of 430 nm under different current densities during pulsed operation.
APPLIED PHYSICS EXPRESS
(2021)
Review
Materials Science, Multidisciplinary
Zhaojun Liu, Byung-Ryool Hyun, Yujia Sheng, Chun-Jung Lin, Mengyuan Changhu, Yonghong Lin, Chih-Hsiang Ho, Jr-Hau He, Hao-Chung Kuo
Summary: Micro-light-emitting diodes (Micro-LEDs) based on gallium nitride (GaN) materials offer versatile platforms for various applications, including displays, data communication tools, photodetectors, and sensors. By combining with quantum dots, Micro-LEDs can achieve efficient full-color displays and high-speed visible light communications.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Physics, Applied
Nicola Roccato, Francesco Piva, Carlo De Santi, Matteo Buffolo, Camille Haller, Jean-Francois Carlin, Nicolas Grandjean, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: The study found that the indium content in InGaN light-emitting diodes has a significant impact on defect density and degradation rate. Results indicate the important role of indium in favoring the incorporation of point defects.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Materials Science, Coatings & Films
KwaDwo Konadu Ansah-Antwi, Chew Beng Soh, Hongfei Liu, Soo Jin Chua
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2015)
Article
Materials Science, Multidisciplinary
Htet Kyaw Ye, S. R. Shannigrahi, C. B. Soh, S. L. W. Yang, L. S. Li, D. V. M. Repka, P. Kumar
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2018)
Article
Computer Science, Information Systems
Xuebing Chen, Feng Wei, Shuyu Cao, Chew Beng Soh, King Jet Tseng
IEEE SYSTEMS JOURNAL
(2020)
Article
Green & Sustainable Science & Technology
Jerome Wei Chiang Teng, Chew Beng Soh, Shiddalingeshwar Channabasappa Devihosur, Ryan Hong Soon Tay, Steve Kardinal Jusuf
Summary: Agrivoltaic systems can make the most of building rooftops and urban farming systems to improve the efficiency of solar photovoltaic (PV) systems. Microclimate simulations and physical prototypes have shown that growing crops underneath the PV canopy can significantly lower PV temperatures and increase energy generation.
Article
Green & Sustainable Science & Technology
Youhanna E. William, Hui An, Szu-Cheng Chien, Chew Beng Soh, Barbara Ting Wei Ang, Toshikazu Ishida, Hikaru Kobayashi, David Tan, Ryan Hong Soon Tay
Summary: The scarcity of land resources and food security challenges in Singapore's urban city have led to the need for more effective use of rooftop and facade spaces. By using BIM modeling and CFD simulation, urban-metabolic farming modules (UmFm) can be simulated and studied for their impact on airflow and solar irradiance. The digital model allows for a prior assessment of feasibility and enables the creation of an eco-resilient farmscape for the urban city.
Proceedings Paper
Engineering, Electrical & Electronic
Valentina Bertolotti, Renato Procopio, Alessandro Rosini, Stefano Bracco, Federico Delfino, Chew Beng Soh, Shuyu Cao, Feng Wei
2020 20TH IEEE INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING AND 2020 4TH IEEE INDUSTRIAL AND COMMERCIAL POWER SYSTEMS EUROPE (EEEIC/I&CPS EUROPE)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
C. B. Soh, C. M. Simon Yu, Samuel Lim, G. S. Kwang, Y. Y. Cheng
2018 JOINT IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 2018 IEEE ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY (EMC/APEMC)
(2018)
Proceedings Paper
Engineering, Electrical & Electronic
N. V. Venkatarayalu, W. W. Lee, D. Tan, C. B. Soh
2017 PROGRESS IN ELECTROMAGNETICS RESEARCH SYMPOSIUM - FALL (PIERS - FALL)
(2017)
Proceedings Paper
Engineering, Multidisciplinary
Gerald Yong Onn Hoo, Chew Beng Soh, Ren Bin Yang, Yu Ying Sim, Samuel Wei Yang Lim
ICMAT 2017 SYMPOSIUM (M TO Z)
(2017)
Proceedings Paper
Engineering, Electrical & Electronic
C. B. Soh, Neelakantam Venkat, C. M. Simon Yu, Darren J. R. Chng
PROCEEDINGS OF THE 2016 IEEE REGION 10 CONFERENCE (TENCON)
(2016)
Article
Materials Science, Multidisciplinary
H. F. Liu, J. Huang, C. G. Li, C. B. Soh, W. Liu, S. J. Chua, D. Z. Chi
JOURNAL OF MOLECULAR AND ENGINEERING MATERIALS
(2015)