Article
Engineering, Electrical & Electronic
Zichen Zhang, Fangliang Gao, Guoqiang Li
Summary: The vertical LEE of UV LEDs can be theoretically enhanced by selecting the band gaps of AlGaN-based nanowire PhC structure. It is found that all gaps can inhibit horizontal propagation of light, with Gap 2 and Gap 3 showing stronger inhibition ability than Gap 1. Additionally, variations in height, number, and refractive index of nanowires impact vertical LEE and optical band gaps.
IEEE PHOTONICS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Yangfeng Li, Rong Yang, Yang Jiang, Haiqiang Jia, Wenxin Wang, Hong Chen
Summary: In this study, we propose a facile and compatible method to reduce the leakage current in InGaN LEDs by inserting an AlGaN interlayer before the growth of n-GaN. The results show that the leakage current is significantly decreased by 37% compared to LEDs without the AlGaN interlayer, while other electronic properties remain unchanged. The AlGaN interlayer effectively blocks the propagation of threading dislocations, contributing to the reduction of leakage current.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Hongchang Tao, Shengrui Xu, Yanrong Cao, Huake Su, Yuan Gao, Yachao Zhang, Jincheng Zhang, Yue Hao
Summary: AlGaN-based UVA LEDs suffer from current crowding at high injection levels due to lateral device structure, leading to non-uniform light emission and overheating. In N-polar UV LEDs, increased hole injection efficiency exacerbates the problem, limiting device performance. This study adopts an n-AlGaN/AlInGaN/AlGaN structure with composition modulation, lattice matching, and a larger bandgap. Numerical results show that this structure promotes current spreading and mitigates hole leakage, enhancing the performance of N-polar UVA LEDs. The use of lattice-matched AlInGaN layers in practical epitaxy is also feasible.
IEEE PHOTONICS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Hongchang Tao, Shengrui Xu, Xiaomeng Fan, Jincheng Zhang, Yue Hao
Summary: The study shows that N-polar AlGaN-based deep ultraviolet LEDs outperform Ga-polar LEDs in terms of light output power and wall-plug efficiency. By introducing a staircase-like p-type interlayer structure, the operation voltage of N-polar LEDs is reduced and the wall-plug efficiency is further increased.
IEEE PHOTONICS JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Yan Zhi, Weici Liu, Xiangbo Yang, Zhongchao Wei, Shiping Du, Hongyun Meng, Hongzhan Liu, Jianping Guo, Liujing Xiang, Zhenming Huang, Haoxian Li, Faqiang Wang
Summary: In this study, a one-dimensional periodic ring multi-connected optical waveguide network is designed to solve the problem of obtaining ultra-wide photonic band gaps. The analysis of the network's spatial structures and numerical relations reveals a common characteristic that the photonic band gap width is independent of the number of nodes in a unit cell of the optical waveguide network. By comparing it with existing optical waveguide network schemes, the potential practicability of the network is explored, showing advantages of lower complexity for the spatial topology, better scalability, and better structural invariance.
RESULTS IN PHYSICS
(2023)
Article
Physics, Applied
Haiyun Tan, Mingjie Zhou, Lanjian Zhuge, Xuemei Wu
Summary: Introducing plasma into the sandwich structure can conveniently turn the photonic band gap on or off, paving the way for tunable microwave applications.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Shu-Jen Wang, Anton Kirch, Michael Sawatzki, Tim Achenbach, Hans Kleemann, Sebastian Reineke, Karl Leo
Summary: Conventional organic optoelectronic devices have low carrier mobility due to disorder. This study presents monolithic integrated triclinic crystal rubrene light-emitting diodes (LEDs) with engineered functional additives. The crystalline LEDs show superior charge transport, operational stability, and long-term stability. However, the crystalline phase reduces the overall performance compared to amorphous rubrene in terms of exciton dynamics and annihilation rates. The potential applications of rubrene and/or its derivatives crystalline films for improving the performance of organic and hybrid optoelectronic devices are discussed.
ADVANCED FUNCTIONAL MATERIALS
(2023)
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
Chioma Vivian Ezeh, Kingsley O. Egbo, Jamaal-Deen Musah, Kin Man Yu
Summary: Gallium oxide (Ga2O3) has attracted significant interest for its wide bandgap and unique properties. Researchers have successfully modified the electronic bands of Ga2O3 through alloying with NiO to achieve p-type conducting Ga2O3-NiO thin films. The films exhibited different structural properties and optical behaviors depending on the Ni content. The p-type alloy films with a high concentration of Ni vacancies showed a wide tunability of bandgap and sub-gap absorption.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Acoustics
Seongmin Park, Wonju Jeon
Summary: Researchers proposed a tapered phononic beam with a unit cell consisting of two identical uniform parts and a thickness- and width-varying part. By controlling the geometrical parameters, the phononic beam achieved an ultra-broad and ultra-low frequency band gap from 3.6 Hz to 237.9 Hz.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Multidisciplinary Sciences
Xiaopeng Zhang, Yangjun Luo, Yi Yan, Pai Liu, Zhan Kang
Summary: A new photonic crystal topological design strategy is proposed to achieve any specified band gap structure around the target frequency. The optimization model introduces a band gap index to measure the distances between specified and adjacent frequencies, utilizing a low number of design variables in the PhC unit cell. The sequential Kriging-based algorithm is applied for solving the optimization problems, resulting in PhC unit cell designs that match any specified central frequency value and achieve a large relative band gap.
ADVANCED THEORY AND SIMULATIONS
(2021)
Article
Engineering, Electrical & Electronic
Yi Lu, Chuanju Wang, Victor Paiva De Oliveira, Zhiyuan Liu, Xiaohang Li
Summary: The study demonstrates the importance of inverse design of n-type and p-type layers in generating opposite polarization-induced fields to suppress electron overflow and enhance hole injection in III-nitride UV LEDs. By utilizing a buried tunneling junction (BTJ) composed of n-AlGaN/i-InGaN/p-AlGaN, significant enhancement in LED output power can be achieved through optimizing the composition and thickness of the InGaN tunneling layer.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Xu Liu, Shengrui Xu, Hongchang Tao, Yanrong Cao, Xinhao Wang, Hengsheng Shan, Jincheng Zhang, Yue Hao
Summary: In this study, the performance improvement of N-polar AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) is investigated by inverting the hole injection layer from N-polar to Ga-polar. The influence of different inversion points on the performance and energy band of DUV LED is systematically studied, and the principle of performance improvement is explained through energy band analysis. An appropriate inversion point is selected based on simulation results and practical application. With polarity inversion of the hole injection layer, the light output power of DUV LEDs increases from 21.34 mW to 29.71 mW, and the applied voltage reduces from 16.06 V to 9.63 V under a current of 120 mA. The DUV LED with polarity inversion shows a 132% increase in wall-plug efficiency (WPE) compared to the DUV LED along the [000-1] direction. Polarity inversion is thus an effective way to achieve high-performance UV-LEDs.
IEEE PHOTONICS JOURNAL
(2023)
Review
Engineering, Electrical & Electronic
Nhat-Khuong Nguyen, Thanh Nguyen, Tuan-Khoa Nguyen, Sharda Yadav, Toan Dinh, Mostafa Kamal Masud, Pradip Singha, Thanh Nho Do, Matthew J. Barton, Hang Thu Ta, Navid Kashaninejad, Chin Hong Ooi, Nam-Trung Nguyen, Hoang-Phuong Phan
Summary: Wearable and implantable bioelectronics have made remarkable progress, but organic materials have limitations. Wide-band-gap materials are emerging as promising candidates for flexible electronics due to their excellent electrical and mechanical properties.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yong Wang, Biaogang Xu, Dengguo Zhang, Wenlong He, Hou Ian
Summary: This study presents a photonic crystal-based isolator design featuring a unique reflecting cavity and built-in fan-shaped coupler, where four Ni-Zn ferrite posts achieve rotations. Despite its compact size of about 46.6 x 41.6 x 4.32 mm(3), the design achieves excellent forward transmission efficiency and reverse isolation of 0.50 dB and 44.20 dB, respectively.
APPLIED SCIENCES-BASEL
(2021)
Article
Physics, Applied
Bing-Cheng Shieh, Yuan-Chang Jhang, Kun-Pin Huang, Wan-Chun Huang, Jing-Jie Dai, Chun-Feng Lai, Chia-Feng Lin
APPLIED PHYSICS EXPRESS
(2015)
Article
Polymer Science
Chi-Jung Chang, Chun-Feng Lai, Wei-Yung Chiou, P. Madhusudhana Reddy, Min-Ju Su
JOURNAL OF APPLIED POLYMER SCIENCE
(2017)
Article
Multidisciplinary Sciences
Guo-Yi Shiu, Kuei-Ting Chen, Feng-Hsu Fan, Kun-Pin Huang, Wei-Ju Hsu, Jing-Jie Dai, Chun-Feng Lai, Chia-Feng Lin
SCIENTIFIC REPORTS
(2016)
Article
Materials Science, Multidisciplinary
Chun-Feng Lai, Yu-Chi Wang, Hsiang-Chih Hsu
JOURNAL OF MATERIALS CHEMISTRY C
(2016)
Article
Crystallography
Chun-Feng Lai, Yu-Chi Wang
Article
Polymer Science
Chi-Jung Chang, Yun-Yi Leong, Chun-Feng Lai, Wei-Yung Chiou, Min-Ju Su, Shinn-Jen Chang
JOURNAL OF APPLIED POLYMER SCIENCE
(2017)
Article
Materials Science, Composites
P. Madhusudhana Reddy, Chi-Jung Chang, Chun-Feng Lai, Min-Ju Su, Mei-Hui Tsai
COMPOSITES SCIENCE AND TECHNOLOGY
(2018)
Article
Chemistry, Multidisciplinary
Chun-Feng Lai, Jia-Sian Li, Ting Fang, Chun-Jen Chien, Chien-Huei Lee
Article
Materials Science, Multidisciplinary
Chun-Feng Lai, Jia-Sian Li
Article
Chemistry, Analytical
Chun-Feng Lai, Jia-Sian Li
SENSORS AND ACTUATORS B-CHEMICAL
(2019)
Article
Chemistry, Multidisciplinary
Chun-Feng Lai, Chang-Zhi Zhong, Yu-Chun Lee
Summary: A highly dense protective layer of Na-poly(Al-O-Si) nanocomposite coating is developed for quantum dot white light-emitting diodes (QD-WLEDs) to enhance their photoluminescence quantum yield and stability. The effects of specific surface area (SSA) of the nanocomposite structures on the reliability of QD-WLEDs are also investigated, and the lowest SSA with the best reliability results is achieved. The developed QDs@NPAS WLEDs exhibit high luminous efficacy, extended operational lifetime, and wide color gamut for display applications.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Chun-Feng Lai, Fu-Jia Shiau
Summary: This study presents and investigates pH-triggered drug-eluting contact lenses (DCLs) combined with large-pore mesoporous silica nanoparticles (LPMSNs). LPMSN-laden DCLs can prolong the residence time of glaucoma drugs in an artificial lacrimal fluid (ALF) environment at pH 7.4 compared to reference DCLs. The LPMSN-laden DCLs do not require drug preloading and are compatible with current contact lens manufacturing processes. LPMSN-laden DCLs soaked at pH 6.5 exhibit better drug loading capabilities than reference DCLs due to specific adsorption.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Chun-Feng Lai, Yu-Ching Chang, Yu-Chien Tien
Summary: Lead-free cesium tin halide double-perovskite nanocrystals were synthesized using a hot injection method and showed hexagonal-shaped structures with cubic symmetry. The experimental results demonstrated the bandgap structures and photoluminescence mechanism of self-trapped excitons in these nanocrystals, as well as their application in LED fabrication.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Chun-Feng Lai, Yu-Chien Tien, Hung-Chun Tong, Chang-Zhi Zhong, Yu-Chun Lee
Article
Nanoscience & Nanotechnology
Chun-Feng Lai, Jia-Sian Li, Chung-Wen Shen
ACS APPLIED MATERIALS & INTERFACES
(2017)
