Article
Engineering, Electrical & Electronic
Feifan Xu, Tao Tao, Dongqi Zhang, Yang Zhang, Yimeng Sang, Junchi Yu, Ting Zhi, Zhe Zhuang, Zili Xie, Rong Zhang, Bin Liu
Summary: We have developed a simple method for producing green and red colors on GaN-based blue micro-light-emitting diodes (mu LEDs) by patterning quantum dots (QDs) using standard photolithography and dry etching. The fabricated QDs exhibited ultra-high resolution and throughput, with a minimum size of 2 μm on a 4-inch wafer. The individual color converted green and red mu LEDs achieved a peak external quantum efficiency (EQE) of 9.6% and 14.7%, respectively. We further demonstrated the monolithic integration of red, green, and blue (RGB) mu LEDs as a single pixel by sequentially patterning red and green QDs. The resulting RGB mu LEDs covered 83.4% of the Rec. 2020 color space in the CIE 1931 diagram. This method enables high-performance red/green mu LEDs with small feature sizes and scalable fabrication of full-color mu LED displays.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
Xifang Chen, Wenhui Wu, Wenxia Zhang, Ziye Wang, Zhenjin Fu, Lei Zhou, Zao Yi, Gongfa Li, Liangcai Zeng
Summary: Carbon quantum dots (CQDs) with graphite core structure were successfully synthesized as white fluorescence CQDs, and the principle of solvent similarity compatibility was used to overcome the agglomeration issue in the process of forming solid film. A solid-state white light emitting device (WLED) was fabricated by embedding CQDs in polymethyl methacrylate matrix, resulting in a cold white light source with high CCT and CIE coordinates.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Amjad Ali, Zeyad A. H. Qasem, Yibin LI, Qian LI, H. Y. Fu
Summary: In recent years, cesium lead bromide and cadmium selenide/zinc sulfide quantum dots have been widely studied to enhance the capacity of visible light communication and solid-state lighting. Liquid-phase color converter glass cavities and solid-phase color converter films were fabricated to investigate and compare their performance. A high-quality white laser diode was fabricated by combining blue LD with color conversion layers, achieving bright white light and high-speed visible light communication capability.
Article
Materials Science, Multidisciplinary
Yong-Ho Ra, Cheul-Ro Lee
Summary: A new approach to reduce the size of photonic device chips is reported, utilizing a monolithic light reflector-nanowire LED system. Vertical cavity nanowire structure for surface-lighting emission is developed using selective area epitaxy, with the light reflection provided by Al metal reflector deposited by MBE technique. The approach shows significantly improved light efficiency at specific spectral wavelength, promising a new route for next-generation photonic and electronic devices.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Article
Optics
Wei Li, Nan Ma, Balaji Devakumar, Xiaoyong Huang
Summary: This study presents a new efficient blue-light-excited Ce3+-doped CaY2HfScAl3O12 green phosphor with broad emission bandwidth and high quantum efficiency. The potential application of this phosphor in fabrication of full-spectrum LED lighting is demonstrated.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Multidisciplinary
Guanghong Yang, Xingxing Tan, Lanlan Zhai, He Huang, Yingyu Wang, Kemin Jiang, Yun Yang, Lijie Zhang, Zhan'ao Tan, Haihong Wen, Yuting Xu, Chao Zou
Summary: Utilizing bromine-based quasi-2D perovskite is a feasible strategy for achieving efficient and stable blue PeLEDs. The phase distribution is modulated by introducing alkali-salt to reduce the n = 1 phase, and a novel Lewis base is proposed as a passivating agent to decrease defects. As a result, the EQE dramatically improves due to the suppression of severe non-radiative recombination losses. Efficient blue PeLEDs with a peak EQE of 3.82% at 487 nm are obtained.
CHEMICAL COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Cheuk Ping Germaine Wong, Albert Ting Leung Lee, Kerui Li, Siew-Chong Tan, S. Y. Hui
Summary: This article introduces a new nonlinear empirical model for achieving precise control over an RGB LED system. The proposed model is experimentally validated and the measured results closely match the predicted values from the model.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Materials Science, Ceramics
Hanxiao Kong, Guang Jia, Huilin Li, Zhaoxin Meng, Ning Zhang, Cuimiao Zhang
Summary: A variety of Bi3+ and/or Eu3+ doped KBaYSi2O7 phosphors with different colors have been successfully synthesized. The Bi3+ doped phosphors show intense cyan emission or unique narrow deep blue emission, which can be used for WLEDs. By adjusting the doping concentrations of Bi3+ and Eu3+, the luminescence colors of KBaYSi2O7 can be tuned. The as-synthesized phosphors exhibit great potential for application in WLEDs and solid-state lighting.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Nonglin Zhou, Jingle Wang, Jia Huang, Shunyin Luo, Xiaona Shao
Summary: The use of organic blue-green emitting materials mixed with green and red phosphors in hybrid WLED devices can greatly improve the color rendering index (CRI) and reduce reliance on rare earth metals. This approach also inspires the design and synthesis of new blue-green materials for future development of hybrid WLEDs.
Article
Optics
Konthoujam James Singh, Xiaotong Fan, Annada Sankar Sadhu, Chun-Ho Lin, Fang-Jyun Liou, Tingzhu Wu, Yu-Jung Lu, Jr-Hau He, Zhong Chen, Tom Wu, Hao-Chung Kuo
Summary: A flexible white-light system for high-speed visible-light communication (VLC) applications is proposed, consisting of a high-bandwidth CsPbBr3 quantum-dot paper and semipolar blue micro-LEDs, which could pave the way for VLC wearable devices.
PHOTONICS RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Wei Li, Nan Ma, Balaji Devakumar, Xiaoyong Huang
Summary: Current commercial white LEDs are typically composed of blue LED chips and yellow phosphors, resulting in cool white-light emissions with low color rendering index due to the lack of red component. There is a need to discover new blue-light-excitable yellow-emitting phosphors with enhanced red emissions for producing high color-quality white LEDs. The novel CaGd2HfScAl3O12:Ce3+ garnet phosphor shows promising potential as a color converter in high-color-quality phosphor-converted white LEDs.
MATERIALS TODAY CHEMISTRY
(2022)
Article
Engineering, Electrical & Electronic
Qiang Su, Heng Zhang, Shuming Chen
Summary: By utilizing transparent QLED elements, individually addressable red/green/blue emissions can be achieved in tandem QLEDs, with the ability to connect QLED elements in series or in parallel to improve external quantum efficiency.
This new implementation strategy for tandem QLEDs shows promising applications in both display and lighting fields, with enhanced EQE.
NPJ FLEXIBLE ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Guangruixing Zou, Zhenchao Li, Ziming Chen, Linghao Chu, Hin-Lap Yip, Yong Cao
Summary: The study proposes a post-treatment method using trichloro(3,3,3-trifluoropropyl) silane to achieve deep-blue emission in perovskite, demonstrating increased bandgap and deep-blue emission through the reaction between chlorine ions and silane molecules. The developed PeLED with deep-blue emission at 458 nm and excellent color stability represents a state-of-the-art result in thin-film PeLEDs.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Krishn Das Patel, Fuh-Shyang Juang, Hao-Xuan Wang, Chong-Zhe Jian, Jia-You Chen
Summary: This study investigated the fabrication process of white organic light-emitting diodes (OLEDs) using red and green quantum dots. By combining them with a blue-emitting layer OLED, the researchers achieved nearly white light emission.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Zishan Yan, Tong Chen, Lingpeng Yan, Xinghua Liu, Jingxia Zheng, Fu-de Ren, Yongzhen Yang, Bin Liu, Xuguang Liu, Bingshe Xu
Summary: White-light emitting carbon dots (WCDs) with high color rendering index (CRI) were prepared through a one-step solvothermal reaction. The WCDs emit white light by combining red, yellow, green, and blue lights. The high CRI value of 97 achieved in WLEDs using the WCDs as phosphors is among the highest reported. Additionally, multicolor LEDs can be fabricated using the four multicolor CDs as phosphors.
Article
Physics, Applied
S. Sergent, B. Damilano, S. Vezian, S. Chenot, T. Tsuchizawa, M. Notomi
APPLIED PHYSICS LETTERS
(2020)
Article
Nanoscience & Nanotechnology
C. Paillet, S. Vezian, C. Matei, A. Michon, B. Damilano, A. Dussaigne, B. Hyot
Article
Physics, Applied
D. Cooper, V. Fan Arcara, B. Damilano, L. Amichi, A. Mavel, N. Rochat, G. Feuillet, A. Courville, S. Vezian, J. Y. Duboz
Summary: Off-axis electron holography has been demonstrated as a unique technique to reproducibly measure the electrostatic potentials in tunnel junctions with nm-scale resolution in III-V device specimens. The method has been used to measure the depletion region width in a series of tunnel junction GaN light emitting diodes and compare the results with simulations and opto-electronic testing, showing consistency in the measurements with the characteristics of the diodes.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Optics
Hui Zi, Yuk Fai Cheung, Benjamin Damilano, Eric Frayssinet, Blandine Alloing, Jean-Yves Duboz, Philippe Boucaud, Fabrice Semond, Hoi Wai Choi
Summary: Optically pumped whispering-gallery mode (WGM) lasing is observed from a thin-film GaN microdisk processed from GaN-on-Si InGaN/GaN multi-quantum well wafers by selective wet-etch removal of the substrate. The surface smoothness of the microdisk is significantly improved compared to those processed from GaN-on-sapphire wafers through laser lift-off. The improved surface smoothness contributes to superior optical confinement and better lasing performance.
Article
Physics, Applied
B. Damilano, S. Vezian, M. P. Chauvat, P. Ruterana, N. Amador-Mendez, S. Collin, M. Tchernycheva, P. Valvin, B. Gil
Summary: InGaN/GaN single quantum wells grown on silicon substrates with thin AlN and GaN buffer layers were made nanoporous using SixNy nanomasking and sublimation, leading to a significant improvement in photoluminescence efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Hui Zi, Wai Yuen Fu, Yuk Fai Cheung, Benjamin Damilano, Eric Frayssinet, Blandine Alloing, Jean-Yves Duboz, Philippe Boucaud, Fabrice Semond, Hoi Wai Choi
Summary: This paper investigates the lasing characteristics of optically-pumped GaN microdisks with different configurations. The microdisks are fabricated from various epitaxial structures and undergo different processes to achieve different degrees of optical confinement. The findings show that the lasing characteristics are influenced by material qualities, optical confinement, and overlap factors with the multi-quantum wells in the microdisk structures.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Applied
P. Vennegues, L. Largeau, V Brandli, B. Damilano, K. Tavernier, R. Bernard, A. Courville, S. Rennesson, F. Semond, G. Feuillet, C. Cornet
Summary: In the first part of this paper, a model is presented to explain and quantify the twists between nucleation islands in Volmer-Weber heteroepitaxial growth of tetrahedrally coordinated semiconductors. The second part of the paper validates the model by studying five systems with different mismatch distributions. The twists of nucleation islands are intrinsic to the material systems and determine the initial microstructure and defect distribution.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Leszek Konczewicz, Sandrine Juillaguet, Marcin Zajac, Elzbieta Litwin-Staszewska, Mohamed Al Khalfioui, Mathieu Leroux, Benjamin Damilano, Julien Brault, Sylvie Contreras
Summary: This article presents the results of low-temperature resistivity and Hall Effect studies of Mg-doped, ammonia-process-grown GaN samples grown on low-temperature buffers of GaN deposited on a sapphire substrate. The temperature dependences of the electrical transport properties before and after the annealing procedure are investigated, and it is found that the low temperatures transport properties are sensitive to the annealing procedure and hopping phenomena must be taken into account to describe the observed effects.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
B. Damilano, S. Vezian, J. Brault, P. Ruterana, B. Gil, M. Tchernycheva
Summary: Nanoporous GaN layers were successfully fabricated using selective area sublimation with an AlN nanomask. The porosity of the layers could be adjusted by changing the nanomask thickness and sublimation conditions. The porous GaN layers showed improved room temperature photoluminescence properties, especially in the 0.4-0.65 porosity range. The characteristics of these porous layers were compared to those obtained with a Si(x)N(y) nanomask, and the regrowth of p-type GaN on light emitting diode structures made porous with different nanomasks were also compared.
Article
Optics
M. Gromovyi, N. Bhat, H. Tronche, P. Baldi, M. EL Kurdi, X. Checoury, B. Damilano, P. Boucaud
Summary: III-nitrides are a versatile platform for nonlinear photonics. This study explores a new configuration, composite waveguides with opposite polarity, and demonstrates significant improvement in conversion efficiency, confirming the theoretical predictions.
Article
Materials Science, Multidisciplinary
R. Aristegui, F. Chiaruttini, B. Jouault, P. Lefebvre, C. Brimont, T. Guillet, M. Vladimirova, S. Chenot, Y. Cordier, B. Damilano
Summary: This study found that excitons in wide GaN/(Al, Ga)N quantum wells are made spatially indirect by a built-in electric field. The density of excitons in traps can be controlled by an external electric bias. Negative bias deepens the trapping potential, while positive bias releases the excitons.
Article
Optics
H. Zi, W. Y. Fu, F. Tabataba-Vakili, H. Kim-Chauveau, E. Frayssinet, P. De Mierry, B. Damilano, J-Y Duboz, Ph Boucaud, F. Semond, H. W. Choi
Summary: Microdisks fabricated with III-nitride materials grown on GaN substrates demonstrate high material quality of homoepitaxial films and advanced micro-fabrication processes. The microdisks achieve an internal quantum efficiency of around 40% and exhibit low threshold optically pumped lasing at the dominant lasing wavelength.
Article
Multidisciplinary Sciences
Q. Song, S. Khadir, S. Vezian, B. Damilano, P. D. Mierry, S. Chenot, V Brandli, P. Genevet
Summary: Any arbitrary state of polarization of light beam can be decomposed into two orthogonal oscillations, each with a specific amplitude of the electric field. The dispersive nature of diffractive and refractive optical components affects these amplitudes over a small wavelength range, altering the properties of light polarization. Recent research suggests the possibility of broadband nanophotonic interfaces to mitigate frequency dispersion, but achieving arbitrary polarization control still presents challenges.
Article
Materials Science, Multidisciplinary
F. Chiaruttini, T. Guillet, C. Brimont, D. Scalbert, S. Cronenberger, B. Jouault, P. Lefebvre, B. Damilano, M. Vladimirova
Summary: Using spatially resolved magnetophotoluminescence spectroscopy, we demonstrated the Mott transition from a dipolar excitonic to an electron-hole plasma state in a wide GaN/(Al,Ga)N quantum well at T = 7 K. The carrier density at the Mott transition was estimated to be approximately 2 x 10^(11) cm^(-2), and the role of excitonic correlations in this process was addressed. Unlike GaAs/(Al,Ga)As systems, where dipolar magnetoexciton transport is strongly quenched by the magnetic field, in GaN/(Al,Ga)N systems, the transport is preserved up to 9 T due to the band parameters.
Article
Engineering, Electrical & Electronic
Ngo Thi Huong, Remi Comyn, Sebastien Chenot, Julien Brault, Benjamin Damilano, Stephane Vezian, Eric Frayssinet, Flavien Cozette, Christophe Rodriguez, Nicolas Defrance, Francois Lecourt, Nathalie Labat, Hassan Maher, Yvon Cordier
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2020)
