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
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
Optics
Himanshu Karan, Abhijit Biswas
Summary: This study reports the optical performance of four InGaN/GaN multiple quantum well (MQW) blue LEDs with different bottom base widths, where the introduction of trapezoidal QW structure aids in reducing the piezoelectric polarization field, promoting carrier distribution uniformity, and increasing radiative recombination rate, with LED C showing the best performance.
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.
Article
Materials Science, Multidisciplinary
Sourav Roy, S. M. Tasmeeh Ahsan, Ashraful Hossain Howlader, Diponkar Kundu, Shakil Mahmud Boby, Md. Rasidul Islam, Md. Shahrukh Adnan Khan, Shuvagoto Dhar, Md. Amzad Hossain
Summary: Semipolar InGaN-made green light-emitting diodes (LEDs) have attracted significant attention for their potential as replacements for polar (0001)-oriented LEDs due to reduced efficiency droop and green gap phenomenon. However, theoretical investigations comparing internal quantum efficiency, output power, and 3 dB bandwidth in non-c-plane-oriented InGaN green LEDs are lacking. This study examines the impact of strain-induced polarization field on major optical and electronic characteristics of In0.29Ga0.71N/GaN green LED along different crystal orientations using a modified ABC model. The results demonstrate that (1122)-oriented InGaN green LED exhibits superior performance in terms of internal quantum efficiency, droop ratio, light emission spectra, output power, and I-V profile.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Crystallography
Yi-Tsung Chang, Mu-Jen Lai, Rui-Sen Liu, Shu-Chang Wang, Xiong Zhang, Lin-Jun Zhang, Yu-Hsien Lin, Shiang-Fu Huang, Lung-Chien Chen, Ray-Ming Lin
Summary: This study found that the current droop in AlGaN-based UVB light-emitting diodes is more noticeable at higher temperatures, despite both the main and parasitic peaks decreasing in intensity with increasing temperature. However, the slower temperature droop does not occur when the forward current is increased to temperatures above 298 K. After a 6000-hour aging period, the emission wavelengths do not show obvious changes, while the intensity of the parasitic peak remains nearly unchanged. Therefore, the degradation in light output power during long-term operation is not significantly correlated to the presence of the parasitic peak.
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
Nanoscience & Nanotechnology
Maosheng Liu, Mingming Jiang, Yang Liu, Kai Tang, Da Ning Shi, Caixia Kan
Summary: This study designed a green LED composed of p-type InGaN layers and one-dimensional conductive ZnO doped with Ga, which showed green wavelength and linewidth characteristics and insensitivity to the Stark effect. The LED demonstrated a color coordinate close to pure green and moderate efficiency droop, indicating potential for solid-state lighting applications.
ACS APPLIED NANO MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Chuanyu Jia, Chenguang He, Zhiwen Liang, Qi Wang
Summary: The study reveals that utilizing In-component-graded InGaN barrier in InGaN light emitting diodes can enhance radiative recombination rate and decrease efficiency droop. The external quantum efficiencies and efficiency droop of LEDs vary with different designs of InGaN barrier, showing the importance of barrier design in LED performance.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
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
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
Crystallography
Pavel Kirilenko, Zhe Zhuang, Daisuke Iida, Martin Velazquez-Rizo, Kazuhiro Ohkawa
Summary: An additional separated peak in the electroluminescence spectrum of red LEDs was observed, caused by defects in the red quantum wells. These defects resulted in shorter-wavelength emissions, different from the main emission peak in red InGaN LEDs.
Article
Optics
JingLin Zhan, ZhiZhong Chen, ChengCheng Li, YiYong Chen, JingXin Nie, ZuoJian Pan, ChuHan Deng, Xin Xi, Fei Jiao, XiangNing Kang, ShunFeng Li, Qi Wang, TongJun Yu, YuZhen Tong, GuoYi Zhang, Bo Shen
Summary: Micro-LEDs can operate at high injection levels, suitable for high-brightness micro-displays and visible light communication, but factors affecting device characteristics become more prominent as current density increases. Coulomb enhancement with polarization screening leads to an abnormal increase in external quantum efficiency at high current densities.
Article
Multidisciplinary Sciences
Woo Jin Baek, Juhyuk Park, Joonsup Shim, Bong Ho Kim, Seongchong Park, Hyun Soo Kim, Dae-Myeong Geum, Sang Hyeon Kim
Summary: InGaN-based micro-light-emitting diodes have the potential to be crucial for next-generation displays. However, efficiency degradations and self-heating issues hinder their development. In this study, Baek et al. demonstrate an epitaxial engineering strategy that reduces lateral carrier diffusion and achieves balanced carrier injection, resulting in high external quantum efficiency and reduced average pixel temperature.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Tae Kyoung Kim, Abu Bashar Mohammad Hamidul Islam, Yu-Jung Cha, Seung Hyun Oh, Joon Seop Kwak
Summary: This work proposes an InGaN/GaN multiple-quantum-well flip-chip blue ultrathin side-emitting LED and improves the light extraction efficiency for increased light output power, making it suitable for backlight units.
Article
Optics
Yizhi Zhu, Heng Guo, Qiannan Cui, Jinping Chen, Zhuxin Li, Junfeng Lu, Tien-Chang Lu, Zhengchun Peng, Chunxiang Xu, Caofeng Pan
Summary: Manipulating photocarrier dynamics for luminescent materials is of fundamental importance for controlling the luminescent properties of optoelectronic devices. This study demonstrates the enhancement and prolongation of photoluminescence through interfacial engineering, which enables resonant coupling between localized surface plasmon and exciton. The photocarrier dynamics at the interface are mediated by plasmon-induced hot electron transfer (PHET) and plasmon-induced resonant energy transfer (PIRET) processes, which can be actively switched on and off by varying the excitation laser wavelength. These findings are highly significant for actively manipulating photocarrier dynamics in perovskite luminescent devices.
LASER & PHOTONICS REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Zhen-Ting Huang, Ting-Wei Chien, Chang-Wei Cheng, Cheng-Ching Li, Kuo-Ping Chen, Shangjr Gwo, Tien-Chang Lu
Summary: Stable electrical modulation of plasmonic nano-lasers is achieved on a hybrid graphene-insulator-metal (GIM) platform at room temperature. A zinc oxide (ZnO) nanowire is placed on the GIM platform to create a plasmonic cavity, and the graphene layer is used for electrical modulation. The lasing thresholds of the ZnO nanowire plasmonic nanolasers on the GIM platform can be modulated by the gate voltage, demonstrating high potential for plasmonic circuit applications.
Article
Engineering, Electrical & Electronic
Chia-Yen Huang, Wen-Hsuan Hsieh, Teng-Li Shao, Chang-Hsien Wu, Tien-Chang Lu
Summary: We reported an unexpected power degradation mechanism in high-power UVC LEDs grown on high-quality AlN templates. Nitrogen desorption, activated by UVC photon emitted from the active region, introduced observable nitrogen loss and created a continuous leakage path from the active region to the p-electrode via various trap-assisted transport mechanisms, resulting in the power degradation of the LEDs.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Multidisciplinary
Jun-Wei Liao, Zhen-Ting Huang, Chia-Hung Wu, Nikita Gagrani, Hark Hoe Tan, Chennupati Jagadish, Kuo-Ping Chen, Tien-Chang Lu
Summary: In this study, localized surface plasmon lasing at room temperature in the communication band was achieved using metallic nanoholes as plasmonic nanocavity and InP nanowires as gain medium. Optimization of laser performance was demonstrated through coupling between two metallic nanoholes, allowing for manipulation of lasing properties. These plasmonic nanolasers offer lower power consumption, smaller mode volumes, and higher spontaneous emission coupling factors, making them promising for high-density sensing and photonic integrated circuits.
Article
Chemistry, Multidisciplinary
Lih-Ren Chen, Chia-Jui Chang, Yi-Jing Wu, Cheng-Lin Liu, Wei Lin, Tien-Chang Lu
Summary: This study presents research on InP-based photonic-crystal surface-emitting lasers (PCSELs) for high-power emission in the L band. The incorporation of embedded air voids within a 2D photonic crystal structure enables vertical laser emission. Investigation into the regrowth processes successfully retained the air holes and achieved an atomically flat p-type surface, resulting in higher output efficiency.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
Chia-Hung Wu, Chih-Jen Ku, Min-Wen Yu, Jhen-Hong Yang, Pei-Yuan Wu, Chen-Bin Huang, Tien-Chang Lu, Jer-Shing Huang, Satoshi Ishii, Kuo-Ping Chen
Summary: This study explores plasmonic photodetection using graphene as a 2D material, achieving non-scattering near-field detection of surface plasmon polaritons. The maximum photoresponsivity is 29.2 mA W-1, and the polarization state of the input light produces a 400% contrast. This has potential applications in on-chip optoelectronic circuits.
Editorial Material
Optics
Jin-Wei Shi, Tien-Chang Lu, Fumio Koyama
Article
Materials Science, Multidisciplinary
Zuhaib Khan, Min-Long Wu, Cheng-Wei Lin, Cheng-Chun Chen, Chia-Jui Chang, Tien-Chang Lu, Nikolay Ledentsov Jr, Nikolay Ledentsov, Jin-Wei Shi
Summary: This article demonstrates a novel layout and arrangement of electrodes for a vertical-cavity surface-emitting laser (VCSEL) array, which improves both its high-speed data transmission performance and the brightness of the output beam. The new design reduces the pitch size between neighboring light emission apertures, allowing downsizing of the whole active area and achieving high brightness output. The demonstrated compact 7 x 7 VCSEL array features separate electrodes for dc current injection and ac signal modulation, leading to improved electrical-optical frequency response, wider bandwidth, and higher brightness output compared to a reference device.
ADVANCED PHOTONICS RESEARCH
(2023)
Article
Nanoscience & Nanotechnology
Chia-Jui Chang, Yu-Wen Chen, Lih-Ren Chen, Kuo-Bin Hong, Jhih-Sheng Wu, Yao-Wei Huang, Tien-Chang Lu
Summary: This article introduces a new method for directly generating vector vortex beams from photonic crystal surface emitting lasers while preserving C-6 rotation symmetry. The ability to dynamically switch between different orders is demonstrated.
Article
Chemistry, Multidisciplinary
Zhen-Ting Huang, Ting-Wei Chien, Chang-Wei Cheng, Cheng-Ching Li, Kuo-Ping Chen, Shangjr Gwo, Tien-Chang Lu
Summary: Stable electrical modulation of plasmonic nanolasers is achieved on a graphene-insulator-metal platform, where the gate voltage can adjust the lasing thresholds of the ZnO nanowire plasmonic nanolasers, providing high-speed modulation characteristics.
Article
Nanoscience & Nanotechnology
Chia-Jui Chang, Lih-Ren Chen, Kuo-Bin Hong, Tien-Chang Lu
Summary: Photonic crystal surface-emitting lasers (PCSELs) have promising properties over traditional semiconductor lasers. However, the minimum achievable lasing threshold of PCSELs is still larger than that of vertical-cavity surface-emitting lasers (VCSELs), limiting its applications. In this study, a new design is proposed to reduce the threshold current of PCSELs by using selective quantum-well intermixing, while maintaining the advantage of small divergence angle.
Article
Chemistry, Physical
Min-Wen Yu, Yu-Tang Lin, Chia-Hung Wu, Tung-Jung Wang, Jhuang-Hao Cyue, Jun Kikkawa, Satoshi Ishii, Tien-Chang Lu, Kuo-Ping Chen
Summary: This work successfully controlled the number of sulfur vacancies in monolayer WS2 flakes synthesized by chemical vapor deposition (CVD), resulting in a difference in photoluminescence (PL) intensity. The sulfur vacancies introduce defect trap states that cause carrier recombination and reduce carrier drift to graphene, thus decreasing the photocurrent. Furthermore, the gate-tunable Fermi level of graphene allows tunable responsivity of the WS2-graphene photodetector.
APPLIED SURFACE SCIENCE
(2024)
Article
Materials Science, Multidisciplinary
Wen-Hui Xu, Yu-Hsun Chou, Zih-Ying Yang, Yi-Yun Liu, Min-Wen Yu, Chen-Hang Huang, Chun-Tse Chang, Chen-Yu Huang, Tien-Chang Lu, Tzy-Rong Lin, Kuo-Ping Chen
Summary: A ZnO-based Tamm plasmon-polariton ultraviolet laser was successfully realized with strong electric field confinement in the active layer. The coupling between TPPs and photons with a Rabi splitting of approximately 30 meV was observed at room temperature. In addition, TPP lasing at 373 nm was clearly observed through optical pumping, and its corresponding characteristics were verified. These results provide a basis for better understanding of the TPP lasing mechanisms.
ADVANCED PHOTONICS RESEARCH
(2022)
Article
Nanoscience & Nanotechnology
Chun-Yen Peng, Hao-Tien Cheng, Yu-Heng Hong, Wen-Cheng Hsu, Fu-He Hsiao, Tien-Chang Lu, Shu-Wei Chang, Shih-Chen Chen, Chao-Hsin Wu, Hao-Chung Kuo
Summary: This study comprehensively analyzes the performance of a commercial photonic-crystal surface-emitting laser (PCSEL) using small-signal measurement and bit-error-rate test. The radio frequency characteristics of the PCSEL are also investigated for the first time. Compared to other types of lasers, the PCSEL shows great potential for a wider optical bandwidth. It is demonstrated that the PCSEL can serve as a promising candidate for high-speed optical communication as a light source.
NANOSCALE RESEARCH LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Zhen-Ting Huang, Kuo-Bin Hong, Ray-Kuang Lee, Laura Pilozzi, Claudio Conti, Jhih-Sheng Wu, Tien-Chang Lu
Summary: In this study, a straightforward and effective design approach for photonic topological insulators supporting high quality factors edge states is proposed using pattern-tunable strain-engineering. Chiral strain-engineering creates opposite synthetic gauge fields in two domains resulting in Landau levels with the same energy spacing but different topological numbers. The strain strongly affects the degree of localization of edge states, while the two-domain design stabilizes the strain-induced topological edge state, providing large scalability for various photonics applications.
