Article
Chemistry, Physical
Li Liu, Qingqing Feng, Yu Zhang, Xiaolu Zhu, Lanli Chen, Zhihua Xiong
Summary: Improving the luminescence efficiency of long wavelength InGaN-based LEDs is a challenging task, and strain-induced piezoelectric effect has been shown to be an effective measure. Reduction of valence band offset at InGaN/GaN heterointerfaces significantly improves hole injection. Tensile strain in the GaN film on a silicon substrate increases the overlap of electron and hole wave functions, leading to enhanced efficiency. Control of the strain-induced piezoelectric polarisation of the InGaN quantum well layer further improves the internal quantum efficiency.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Optics
Yang Mei, Yan-hui Chen, Lei-ying Ying, Ai-qin Tian, Guo-en Weng, Long Hao, Jian-ping Liu, Bao-ping Zhang
Summary: Dual-wavelength switchable emission has been achieved in InGaN QD micro-cavity light-emitting diodes. By modulating the injected current levels, the device can switch between two distinct cavity modes in the green spectral range. The microcavity effect enables high spectral purity. This study provides important guidelines for controllable dual-wavelength switchable operation in nitride-based light-emitting devices.
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)
Review
Crystallography
Panpan Li, Hongjian Li, Matthew S. Wong, Philip Chan, Yunxuan Yang, Haojun Zhang, Mike Iza, James S. Speck, Shuji Nakamura, Steven P. Denbaars
Summary: InGaN-based red micro-size light-emitting diodes (μLEDs) are highly attractive due to their less influenced external quantum efficiency (EQE) by size effect compared to common AlInGaP-based red μLEDs. Additionally, InGaN red μLEDs exhibit robust device performance even at high temperatures up to 400K. This review discusses the progress of InGaN red μLEDs and explores novel growth methods to relax the strain and increase the growth temperature of InGaN red quantum wells.
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
Yuan Xie, Wansheng Liu, Wanyuan Deng, Haimei Wu, Weiping Wang, Yichuan Si, Xiaowei Zhan, Chao Gao, Xian-Kai Chen, Hongbin Wu, Junbiao Peng, Yong Cao
Summary: This study reports on the potential applications of high-efficiency organic light-emitting diodes (OLEG) in the short-wavelength infrared (SWIR) region. By using specific types of molecules, researchers have successfully fabricated high radiance SWIR OLEGs, which have various applications in biosensors, biomedical imaging and spectroscopy, and surveillance.
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
Engineering, Electrical & Electronic
Jiahao Yin, Xiaoshuai An, Liang Chen, Jing Li, Jianan Wu, Yumeng Luo, Qing Wang, Hongyu Yu, Kwai Hei Li
Summary: The study focused on monolithic integrated photodetectors (PDs) in InGaN/GaN LEDs for monitoring LED intensity fluctuations. Through simulation and experiments, it was found that placing the PD in the center of the LED resulted in a 58% increase in detected photocurrent with minimal impact on the LED emission profile compared to placing the PD at the edge. Encapsulating the LED-PD device with yellow phosphor enabled white light emission, and the on-chip PD showed similar sensing behaviors to an external Si-based photodiode. The optimal monolithic PD design offered comparable sensing capabilities, compactness, insensitivity to ambient lighting, and minimal influence on the LED emission profile, making it suitable for real-time monitoring of LED intensity in practical and scientific lighting applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Chemistry, Multidisciplinary
Pan Yin, Ting Zhi, Tao Tao, Xiaoyan Liu
Summary: In this study, GaN-based blue micro-light-emitting diodes (mu-LEDs) with different structures were designed, and the effect of quantum well (QW) structure on modulation bandwidth was explored. It was found that trapezoidal QWs can enhance modulation bandwidth and improve carrier lifetime.
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
Katarzyna Pieniak, Witold Trzeciakowski, Grzegorz Muziol, Anna Kafar, Marcin Siekacz, Czeslaw Skierbiszewski, Tadeusz Suski
Summary: The study examined electroluminescence from In0.17Ga0.83N/GaN quantum wells of LEDs and LDs, finding a transition from ground-states recombination to excited states recombination with increasing QW width. The effect is accompanied by partial or complete screening of the built-in electric field with increasing driving current, which was studied using a high pressure method. Investigations were supported by simulations of the variation with driving current of electron and hole wavefunctions overlap affecting the recombination channel and built-in electric field.
Article
Chemistry, Multidisciplinary
Hongjing Han, Sujuan Hu, Shilong Zhang, Xiaojun Li, Hailing Sun, Jiawen Chen, Baiquan Liu, Chuan Liu, Wangqiao Chen, Qichun Zhang
Summary: In this study, two new pyrene-based polyaromatic hydrocarbons (PAHs) were designed and synthesized as emitting layer materials in OLED devices, and the change in molecular structure resulted in a transition from greenish to white emission. Further investigation revealed that the bis-fused molecule formed excimers in the solid state, broadening the emission spectrum of the OLEDs.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Optics
Zhe Zhuang, Daisuke Iida, Martin Velazquez-Rizo, Kazuhiro Ohkawa
Summary: The study introduced a method for fabricating ultra-small InGaN μLEDs, successfully realizing different shapes of green μLEDs. It was found that as the size of the μLED decreases, the series resistance and turn-on voltage increase, while the light output power density and external quantum efficiency also improve.
Article
Materials Science, Multidisciplinary
Liwen Cheng, Xingyu Lin, Zhenwei Li, Da Yang, Jiayi Zhang, Jundi Wang, Jiarong Zhang, Yuru Jiang
Summary: InGaN LEDs with IGIT barriers have higher light output power, lower turn-on voltage, and less efficiency droop compared to LEDs with conventional GaN and InGaN barriers. These improvements are a result of the appropriately designed energy band diagram, which enhances hole injection efficiency and electron confinement.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Mohammad Hossein Alam Varzaneh Isfahani, Rahim Faez
Summary: A novel structure is proposed in this paper to decrease the polarization charges of quantum wells, aiming to improve the efficiency of light-emitting diodes and enhance radiative recombination rates. Energy bands diagram and carriers density are used to demonstrate the superior performance of the new structures, showing an increase in carriers injection in the new structures.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
