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
Engineering, Electrical & Electronic
Matthew Hartensveld
Summary: A color tunable micro light emitting diode (mu LED) array is fabricated using Indium Gallium Nitride (InGaN) to address the challenges of material differences and integration. This work provides the basis for the application of V-groove color tunable mu LEDs in displays.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Materials Science, Ceramics
Xiaomeng Wang, Zhou Zhao, Miao Deng, Zhenrui Yang, Qiqi Wu, Wentao Zhang
Summary: The white-emitting phosphor Na5Y(MoO4)4:Dy3+, Tm3+ was prepared using the sol-combustion method, with color-tunable white emission achieved through Tm3+ codoping.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Multidisciplinary
Ge Mu, Tianyu Rao, Yawei Qi, Su Ma, Qun Hao, Menglu Chen, Xin Tang
Summary: An optoelectronic device called color-tunable organic light-emitting diode (CTOLED) is developed to achieve interactive signal visualization in the intelligent era. The device enables multicolor visualization of infrared light and temperature distribution through a multi-stimuli responsive silicon sensor. It offers the user the ability to manipulate the device using an infrared pen, influencing the displayed patterns and colors. Additionally, the device can sense temperature and display it in different colors, making it a promising wearable temperature visualization monitor.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Hsing-Kun Shih, Chun-Nien Liu, Wei-Chih Cheng, Wood-Hi Cheng
Summary: In this study, co-doped phosphor-in-glass (PiG) with a suitable selection of red and green phosphors and antireflection coating (ARC) has been demonstrated for high performance white light-emitting diodes (WLEDs). This approach led to improved overall luminous efficiency, higher color rendering index, and reduced amount of phosphor material usage, making it economically viable for high-quality WLED indoor lighting applications.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Yun Zhao, Bingli Gu, Guoqiang Guo, Yanshuang Li, Tingting Li, Yuejin Zhu, Xu Wang, Da Chen
Summary: Blue, green, and red graphene quantum dots (GQDs) were synthesized and used for pattern printing and multicolor anticounterfeiting. White light-emitting diodes (LEDs) with high color rendering index and correlated color temperature were fabricated. This research expands the potential applications of GQDs in anticounterfeiting and LED technology.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Xianhe Liu, Yi Sun, Yakshita Malhotra, Ayush Pandey, Yuanpeng Wu, Kai Sun, Zetian Mi
Summary: This study focuses on InGaN nanowire green light emitting diodes (LEDs) with lateral dimensions varying from about 1 to 10 micrometers. The research shows that a maximum external quantum efficiency of around 5.5% can be achieved for devices with an areal size of about 3 x 3 micrometers without any packaging. By optimizing light extraction efficiency, reducing point defect formation, and controlling electron overflow, the external quantum efficiency of InGaN nanowire micro-LEDs has the potential to reach 30%-90%.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Mingjun Song, Wang Zhao, Junpeng Xue, Lintong Wang, Jing Wang
Summary: This article presents a systematic study on the structure, tunable luminescence, and temperature sensing properties of Bi3+, Sm3+ singly/co-doped La2LiSbO6 phosphors prepared via solid state reaction method. The results show efficient energy transfer from Bi3+ to Sm3+ ions in La2LiSbO6:Bi3+, Sm3+ phosphors, leading to excellent optical sensitivity to temperatures. Additionally, the study evaluates the potential application of La2LiSbO6:Sm3+ phosphor in indoor illumination based on the fabricated LED's photoelectric parameters.
JOURNAL OF LUMINESCENCE
(2021)
Article
Optics
Jingxin Nie, Zhizhong Chen, Fei Jiao, Jinglin Zhan, Yifan Chen, Yiyong Chen, Zuojian Pan, Xiangning Kang, Yongzhi Wang, Qi Wang, Tianhang Zhou, Weimin Dang, Wentian Dong, Shuzhe Zhou, Xin Yu, Guoyi Zhang, Bo Shen
Summary: The study uses purple and azure LEDs for mixing to achieve high color fidelity white light, following the relevant chromaticity diagram for selecting other monochromatic LEDs. By optimizing peak wavelengths with mathematical models and constraints on chromaticity coordinates, the blue light hazard efficiency of the white light is kept below 0.06. Comprehensive measurements reveal high color rendering index, color fidelity score, and color gamut score for the mixed white light.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Xuehua Shen, Huanting Chen, Wenjie Zhang, Xiaoxi Ji, Yan Yi
Summary: This paper focuses on dynamic dimming for phosphor-converted (PC) white LEDs to achieve adjustable correlated color temperature (CCT) and adequate color rendering index (CRI) by compensating for red/green spectra. The proposed tunable dimming models involve multi-physics effects and the nonlinear characteristics are observed. Experimental verifications show good agreement between calculations and measurements, indicating the effectiveness of the proposed models in understanding photometric characteristics and visual perception of illumination.
IEEE PHOTONICS JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Jongchan Kim, Vivian Wang, Seung Chan Kim, Jun Yeob Lee, Ali Javey
Summary: We demonstrate an AC-driven light emitting capacitor that can change the color of the emission spectra by adjusting the applied AC frequency. The device has a simple MOS capacitor structure with an organic emissive layer, allowing for easy fabrication. The emission of low energy dyes dominates at low frequency, while the emission of high energy dyes from the host matrix dominates at high frequency. This color tunable device has potential applications in future full-color displays and lighting.
Article
Chemistry, Physical
Qian Zhang, Wanyin Ge, Xinmeng Zhang, Yie Tian, Zheng Yin
Summary: Researchers achieved a new single-phase white light phosphor (Si NPs-M) by grafting silicon-based nanoparticles onto a red lanthanide coordination polymer using a simple wet chemical method, enabling modulation of white light. The energy transfer mechanism of the phosphor is controlled by changing the local site of ion coordination to fine-tune its emitted chromaticity. The resulting white light-emitting diodes (WLEDs) demonstrated desirable color coordinates, color rendering index (CRI), and correlated color temperature (CCT). The WLEDs also exhibited good optical stability and high stability under increased drive current and elevated external temperature. This research has potential applications for silicon-compatible display technologies that require precise control of efficient white light emission.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Multidisciplinary
X. Li, S. Chen, K. Zhang, S. Deng, J. He, B. Wang, Q. Zeng
Summary: This study investigates the persistent luminescence properties of sodium yttrium silicate doped with europium or cerium using a solid-state approach. The phosphors exhibited blue/green emissions under UV irradiation, and persistent luminescence was observed in both single-doped and co-doped samples. The tunable persistent luminescence and potential applications in fingerprint identification and anti-counterfeiting were demonstrated.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Chemistry, Physical
Joonseo Park, Jin-Woong Lee, Satendra Pal Singh, Minseuk Kim, Byung Do Lee, Woon Bae Park, Kee -Sun Sohn
Summary: A novel quaternary sulfide phosphor emitting cyan light was discovered and found to be suitable for LED applications due to its high photoluminescence intensity and optimal crystallinity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Optics
DiFeng Yin, Yuan Zhou, Zhaoxiang Liu, Zhe Wang, Haisu Zhang, Zhiwei Fang, Wei Chu, Rongbo Wu, Jianhao Zhang, Wei Chen, Min Wang, Ya Cheng
Summary: This study demonstrates the monolithic integration of an electrooptically tunable microring laser on a lithium niobate on insulator (LNOI) platform. The device fabrication involves photolithography assisted chemo-mechanical etching, and the microring resonator exhibits a high quality factor of 1.54 x 10(5) at a wavelength of 1542 nm. Lasing action is observed at a pump power threshold below 3.5 mW, with the laser wavelength tunable through varying the electric voltage on microelectrodes.
Article
Engineering, Electrical & Electronic
Deepak Kumar Panda, Trupti Ranjan Lenka, Rajan Singh, Vishal Goyal, Nour El Islam Boukortt, Hieu Pham Trung Nguyen
Summary: In this paper, a dielectric modulated negative capacitance MoS2 FET-based biosensor is proposed for label-free detection of biomolecules. The sensing mechanism relies on the immobilization of biomolecules in a nanocavity formed below the gate, leading to variations in various electrostatic properties. An analytical model is developed and validated, and the results show that the proposed device can be used as a next-generation low-power label-free biosensor with enhanced sensitivity.
INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS
(2023)
Article
Physics, Applied
Ding Wang, Ping Wang, Shubham Mondal, Mingtao Hu, Danhao Wang, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: The thickness scaling behavior of ferroelectric Sc0.3Al0.7N films grown on Mo substrates by molecular beam epitaxy is reported. The switchable ferroelectricity in ScAlN films with thicknesses ranging from 100 to 5 nm is confirmed. The increase in coercive field and diminution of remnant polarization in films below 20 nm are closely related to surface oxidation and strain state in ultrathin ScAlN films.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Ayush Pandey, Jungwook Min, Maddaka Reddeppa, Yakshita Malhotra, Yixin Xiao, Yuanpeng Wu, Kai Sun, Zetian Mi
Summary: By developing nanowire excitonic LEDs, the challenge of reduced efficiency in quantum well LEDs at small dimensions can be overcome. A submicron scale green-emitting LED with an external quantum efficiency of 25.2% and a wall-plug efficiency of 20.7% was achieved, the highest values reported for LEDs of this size to our knowledge. Critical factors for achieving excitonic micro-LEDs were identified, including epitaxy of nanostructures for strain relaxation, utilization of semipolar planes to minimize polarization effects, and formation of nanoscale quantum confinement to enhance electron-hole wave function overlap. This work provides a viable path to break the efficiency bottleneck of nanoscale optoelectronics.
Article
Multidisciplinary Sciences
Peng Zhou, Ishtiaque Ahmed Navid, Yongjin Ma, Yixin Xiao, Ping Wang, Zhengwei Ye, Baowen Zhou, Kai Sun, Zetian Mi
Summary: Production of hydrogen fuel from sunlight and water is a promising pathway for carbon neutrality. A strategy using pure water, concentrated solar light, and an indium gallium nitride photocatalyst has achieved a solar-to-hydrogen efficiency of 9.2%. The strategy promotes forward hydrogen-oxygen evolution and inhibits reverse hydrogen-oxygen recombination by operating at an optimal reaction temperature, which can be achieved by harvesting infrared light in sunlight.
Review
Engineering, Electrical & Electronic
Ping Wang, Ding Wang, Shubham Mondal, Mingtao Hu, Jiangnan Liu, Zetian Mi
Summary: III-nitride semiconductors have been extensively studied as promising optoelectronic and electronic materials in the past decades. Recent experimental demonstrations of ferroelectricity in nitride materials have led to significant research interest and expanded their potential in next-generation technologies. Nitride ferroelectric semiconductors, with their unique advantages such as high polarization, breakdown field, Curie temperature, and enhanced optical properties, have enabled a wide range of applications in various devices and systems. This review discusses the development of nitride ferroelectric semiconductors from materials to devices, highlighting their advantages, achievements, challenges, and prospects.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Applied
Ding Wang, Ping Wang, Minming He, Jiangnan Liu, Shubham Mondal, Mingtao Hu, Danhao Wang, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: In this Letter, fully epitaxial ScAlN/AlGaN/GaN based ferroelectric high electron mobility transistors (HEMTs) were demonstrated using molecular beam epitaxy. The fabricated ferroelectric gate HEMTs showed counterclockwise hysteretic transfer curves with a wide threshold voltage tuning range, a large ON/OFF ratio, and reconfigurable output characteristics. The high quality ferroelectric gate stack and effective ferroelectric polarization coupling lead to improved subthreshold performance. These results provide fundamental insight into the ferroelectric polarization coupling and threshold tuning processes in ferroelectric nitride heterostructures and have promising applications in next-generation electronics.
APPLIED PHYSICS LETTERS
(2023)
Editorial Material
Materials Science, Multidisciplinary
Grace Xing, Zetian Mi, Srabanti Chowdhury
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Jiarui Gong, Jie Zhou, Ping Wang, Tae-Hyeon Kim, Kuangye Lu, Seunghwan Min, Ranveer Singh, Moheb Sheikhi, Haris Naeem Abbasi, Daniel Vincent, Ding Wang, Neil Campbell, Timothy Grotjohn, Mark Rzchowski, Jeehwan Kim, Edward T. Yu, Zetian Mi, Zhenqiang Ma
Summary: This study successfully demonstrates the creation, transfer-printing, and characteristics of high-quality single-crystalline aluminum nitride nanomembranes (AlN NMs). The crystalline quality of the NMs remains intact after transfer, and partial relaxation of tensile stress is observed. Additionally, piezoelectricity at the nanoscale is confirmed. This research provides a novel approach for the development of AlN-based heterogeneous integration and future nanoelectronics and optoelectronics.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
David Arto Laleyan, Woncheol Lee, Ying Zhao, Yuanpeng Wu, Ping Wang, Jun Song, Emmanouil Kioupakis, Zetian Mi
Summary: Two-dimensional hexagonal boron nitride (h-BN) shows great promise for far ultraviolet (UV-C) light emission with higher quantum efficiency than other indirect bandgap materials, enabled by strong excitonic effects and efficient exciton-phonon interactions. This study offers a new approach for the design and development of far UV-C optoelectronic devices and quantum photonic devices using 2D semiconductor active regions.
Article
Engineering, Electrical & Electronic
Rabin Paul, Trupti Ranjan Lenka, Fazal Ahmed Talukdar, Nour El Islam Boukortt, Hieu Pham Trung Nguyen
Summary: The ultrathin-film solar cell technology utilizing chalcogenide materials like CIGS, CZTS, and CZTSe has shown promising performance. This study proposes a single-layer a-Si/CZTSe structure for the UTFSC, which exhibits an efficiency of 10.99% at optimized thicknesses. Introducing defects in the CZTSe layer reduces the cell's performance to 10.58%. The results suggest a potential for further development of UTFSC using nontoxic materials and a simple fabrication process.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Samadrita Das, Trupti Ranjan Lenka, Fazal Ahmed Talukdar, Hieu Pham Trung Nguyen, Giovanni Crupi
Summary: In this paper, an electron blocking layer (EBL) free light emitting diode (LED) nanowire with prestrained layers has been proposed. The prestrained layers of InxGa1-xN/GaN are inserted between the GaN/InGaN multi-quantum wells (MQWs) and n-GaN layer to enhance the luminescence of the LED nanowires. The efficiency of the LED nanowire with prestrained layer has been improved by approximately 2.897% compared to the conventional one, due to the reduction of polarization field in the active region. The LED with 15% indium in the prestrained layer achieves a maximum efficiency of 85.21% with a minimum efficiency droop of 3.848% at 40 mA injected current. The proposed III-nitride LED nanostructure allows for superior optical power across the output spectral range.
INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS
(2023)
Article
Engineering, Electrical & Electronic
Suhyun Nam, Wenhao Peng, Ping Wang, Ding Wang, Zetian Mi, Amir Mortazawi
Summary: Modern wireless communication systems are becoming more complex and pose new challenges for RF front-end design. This study introduces a film bulk acoustic wave resonator (FBAR) with a composite ferroelectric/piezoelectric transduction layer that can operate selectively at higher order resonant modes in the millimeter wave spectrum without compromising k(t)(2). The resonator has a fundamental mode at GHz with k(t)(2) of 5.2%, but can switch to a higher order response at 31 GHz with k(t)(2) of 5.5%).
IEEE MICROWAVE AND WIRELESS TECHNOLOGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Thi Tuyet Doan, Thanh Quang Le, Boi An Tran, Tung Cao-Thanh Pham, Ravi Teja Velpula, Mano Bala Sankar Muthu, Hieu Pham Trung Nguyen, Quan Thi Hong Vu, Przemyslaw Jacek Deren, Hoang-Duy Nguyen
Summary: Red-emitting alumina nanophosphors doped with Mn4+ and Mg2+ (Al2O3:Mn4+, Mg2+) were synthesized by a hydrothermal method. The prepared samples exhibited different phases depending on the annealing temperature, with cubic gamma-Al2O3 phase at 500°C, tetragonal delta-Al2O3 phase at 1000°C, and rhombohedral alpha-Al2O3 phase at 1300°C. The emission spectra showed strong peaks at 678 and 692 nm due to Mn4+ ion transitions. The nanophosphors had excellent waterproof ability and thermal stability. Additionally, the nanophosphors improved the current-voltage characteristic of nanowire LEDs due to increased heat dissipation.
Proceedings Paper
Engineering, Electrical & Electronic
Samadrita Das, Trupti Ranjan Lenka, F. A. Talukdar, Ravi Teja Velpula, Hieu Pham Trung Nguyen
Summary: The grayscale composition in the barriers of multi-quantum can enhance the carrier transportation and mitigate the efficiency droop in c-plane GaN/AlGaN LEDs. The optimized LEDs with graded aluminum composition exhibit higher internal quantum efficiency and lower series resistance compared to conventional devices, resulting in improved carrier transport and reduced efficiency droop.
MICRO AND NANOELECTRONICS DEVICES, CIRCUITS AND SYSTEMS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Ravi Teja Velpula, Barsha Jain, Samadrita Das, Trupti Ranjan Lenka, Hieu Pham Trung Nguyen
Summary: The article introduces a novel EBL-free AlGaN UV LED structure with polarization-controlled composition-graded convex quantum barriers. It improves the internal quantum efficiency and output power, and has the potential to generate high-power deep UV light sources for practical applications.
MICRO AND NANOELECTRONICS DEVICES, CIRCUITS AND SYSTEMS
(2023)
