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
Chemistry, Multidisciplinary
Vladimir Neplokh, Vladimir Fedorov, Alexey Mozharov, Fedor Kochetkov, Konstantin Shugurov, Eduard Moiseev, Nuno Amador-Mendez, Tatiana Statsenko, Sofia Morozova, Dmitry Krasnikov, Albert G. Nasibulin, Regina Islamova, George Cirlin, Maria Tchernycheva, Ivan Mukhin
Summary: Flexible red light-emitting diodes based on GaPAs/GaP axial nanowires embedded in polydimethylsiloxane membranes with transparent electrodes involving single-walled carbon nanotubes were demonstrated. The devices showed similar electroluminescence properties compared to those processed directly on Si growth substrate, indicating potential for flexible full color inorganic devices.
Article
Nanoscience & Nanotechnology
Anthony Aiello, Debabrata Das, Pallab Bhattacharya
Summary: In this study, InGaN/GaN quantum dot light-emitting diodes were demonstrated on silicon substrates with a planar buffer layer formed by coalescing GaN nanowires. The devices showed strong electroluminescence with a minimal blue shift and a polarization field. However, efficiency droop was observed beyond an injection of 40A/cm(2), possibly due to defect-assisted Auger recombination and carrier leakage from the active region.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Sung-Un Kim, Yong-Ho Ra
Summary: The study successfully developed high-concentration InGaN and long-InGaN nanowire heterostructures on silicon substrate using molecular beam epitaxy (MBE) system, improving crystal quality and significantly enhancing optical properties.
Article
Chemistry, Multidisciplinary
Liliia Dvoretckaia, Vladislav Gridchin, Alexey Mozharov, Alina Maksimova, Anna Dragunova, Ivan Melnichenko, Dmitry Mitin, Alexandr Vinogradov, Ivan Mukhin, Georgy Cirlin
Summary: The direct integration of epitaxial III-V and III-N heterostructures on Si substrates provides a promising platform for the development of optoelectronic devices. This study presents the molecular beam epitaxy of ordered arrays of n-GaN/i-InGaN/p-GaN heterostructured nanowires and tripods on Si/SiO2 substrates using cost-effective and rapid microsphere optical lithography. The fabricated n-GaN/i-InGaN/p-GaN NWs-based LEDs exhibit electroluminescence in a broad spectral range, with a maximum near 500 nm, which can be utilized for the development of multicolor or white light screens.
Article
Nanoscience & Nanotechnology
Andreas Liudi Mulyo, Anjan Mukherjee, Ida Marie Hoiaas, Lyubomir Ahtapodov, Tron Arne Nilsen, Havard Hem Toftevaag, Per Erik Vullum, Katsumi Kishino, Helge Weman, Bjorn-Ove Fimland
Summary: This study successfully demonstrates the fabrication of flip-chip ultraviolet light-emitting diodes based on self-assembled GaN/AlGaN nanocolumns, using single-layer graphene as both a growth substrate and a transparent conducting electrode. The high crystalline quality of the nanocolumns and the presence of intrinsic GaN quantum disk are confirmed through detailed electron microscopy characterization. The optical emission characteristics reveal the absence of defect-related yellow emission and the presence of blue-shifted emission, attributed to quantum confinement and strain effects.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Hedong Chen, Peng Wang, Xingyu Wang, Xingfu Wang, Lujia Rao, Yinping Qian, Hongjie Yin, Xianhua Hou, Huapeng Ye, Guofu Zhou, Richard Notzel
Summary: This study explores III-nitride nanowire anti-reflection structures for solar water splitting. Vertical InGaN nanowire arrays tilted by 73 degrees exhibit maximized photocurrent. By growing 3D InGaN nanowire arrays on inclined pyramid-textured Si, various light trapping effects lead to 500% enhancement in photocurrent compared to NWs on a planar Si substrate.
Article
Optics
Yuanpeng Wu, Yixin Xiao, Ishtiaque Navid, Kai Sun, Yakshita Malhotra, Ping Wang, Ding Wang, Yuanxiang Xu, Ayush Pandey, Maddaka Reddeppa, Walter Shin, Jiangnan Liu, Jungwook Min, Zetian Mi
Summary: Micro or submicron scale light-emitting diodes (mu LEDs) have been extensively studied as the next-generation display technology. However, achieving high stability and efficiency, submicron pixel size, and integration with CMOS electronics has remained a challenge. This study reports the successful growth of mu LEDs on silicon with stable, bright green emission, and negligible quantum-confined Stark effect. The use of AlGaN barriers effectively compensates for the strain within the active region, improving indium incorporation without compromising material quality. This research provides insights and a viable approach for high-performance mu LEDs on silicon.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Engineering, Environmental
Hedong Chen, Peng Wang, Huapeng Ye, Hongjie Yin, Lujia Rao, Dantong Luo, Xianhua Hou, Guofu Zhou, Richard Noetzel
Summary: In this study, InGaN nanowires were synthesized on pyramid textured Si substrates to create a novel anti-reflection 3D nano-grating light trapping structure, leading to enhanced photoelectrocatalytic water splitting efficiency. The research was verified theoretically through Finite Difference Time Domain (FDTD) simulations.
CHEMICAL ENGINEERING JOURNAL
(2021)
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)
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
Chemistry, Multidisciplinary
Xiangyu Fu, Yash Mehta, Yi-An Chen, Lei Lei, Liping Zhu, Nilesh Barange, Qi Dong, Shichen Yin, Juliana Mendes, Siliang He, Renuka Gogusetti, Chih-Hao Chang, Franky So
Summary: The study demonstrates highly directional and polarized light emission from LEDs by selectively diffracting the TE waveguide mode, showing potential for more efficient photonic applications.
ADVANCED MATERIALS
(2021)
Article
Optics
Jie Zhao, Yu Yin, Renfeng Chen, Xiang Zhang, Junxue Ran, Hao Long, Junxi Wang, Tongbo Wei
Summary: In this Letter, the fabrication of three dimensional truncated-hexagonal-pyramid (THP) vertical light emitting diodes (VLEDs) with white emission grown on beta-Ga2O3 substrate is described. The longitudinal growth rate of the 3D n-GaN layer increases with decreasing N-2 flow rate and increasing H-2 flow rate. The 3D THP VLED effectively suppresses the quantum-confined Stark effect (QCSE) and improves the internal quantum efficiency (IQE), while reducing the V-shaped pits. Furthermore, the 3D THP VLED achieves multiwavelength emission and better light extraction efficiency (LEE), offering a promising approach for phosphor-free white LED devices.
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
Vladislav O. Gridchin, Konstantin P. Kotlyar, Rodion R. Reznik, Anna S. Dragunova, Natalia Kryzhanovskaya, Vera V. Lendyashova, Demid A. Kirilenko, Ilya P. Soshnikov, Dmitrii S. Shevchuk, George G. Cirlin
Summary: This study investigates the influence of growth conditions on the physical and optical properties of InGaN nanowires, showing that a slight change in growth temperature can lead to significant changes in the structural and optical properties of the nanowires. The results suggest a novel approach for monolithic growth of InGaN nanowires with multi-color light emission on Si substrates by setting a temperature gradient over the substrate surface.
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, Physical
Jiahua Zhang, Hongsen He, Tongtong Zhang, Lingzhi Wang, Madhav Gupta, Jixiang Jing, Zhongqiang Wang, Qi Wang, Kwai Hei Li, Kenneth Kin-Yip Wong, Zhiqin Chu
Summary: In this paper, ultrasensitive all-optical nanothermometry using high figure-of-merit nanodiamonds with silicon-vacancy (SiV) centers is introduced. The two-photon approach is adopted to efficiently excite the SiV centers in nanodiamonds. With the developed intensity-projected scheme, a noise floor of 6.6 mK center dot Hz-1/2 is achieved experimentally, which sets a new record of temperature resolution in the relevant field. This simplified method allows reflecting the temperature-induced spectral shift without wavelength scanning via a spectrometer. Furthermore, the thermal activation of two-photon excitation of SiV centers is demonstrated.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Applied
Zhiwen Liang, Ye Yuan, Pengwei Wang, JunJie Kang, Qi Wang, Guoyi Zhang
Summary: This study comprehensively investigated the ex situ sputtered AlN buffer and GaN epilayer grown by metalorganic chemical vapor deposition. The study revealed that the AlN buffer deposited by sputtering technique could be oxidized in the atmosphere, which significantly affected the characteristics of the GaN epilayer. This finding has important guiding significance for the growth of high-quality III-nitride materials.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(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 using a hydrothermal method and Pluronic surfactant. The nanophosphors showed different phases depending on the annealed temperature, with cube-like nanoparticles observed at 500-1000°C. The phosphors exhibited strong red emission at 678 and 692 nm due to the transitions of Mn4+ ions, and displayed excellent waterproof ability and thermal stability. Combining the nanophosphors with InxGa(1-x)N nanowire chips, warm-white LEDs with high color rendering index and low correlated color temperature were achieved. The use of nanophosphors also improved the current-voltage characteristic of the LEDs.
Article
Nanoscience & Nanotechnology
Ping Wang, Ding Wang, Shubham Mondal, Mingtao Hu, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: Achieving ferroelectricity in III-nitride semiconductors by alloying with rare-earth elements, such as scandium, has opened up possibilities for next-generation electronic, acoustic, photonic, and quantum devices and systems. However, the integration of nitride semiconductors with the complementary metal oxide semiconductor (CMOS) technology has been hindered by the need for sapphire, Si, or SiC substrates. In this study, we demonstrate the growth of single-crystalline ferroelectric nitride semiconductors on CMOS compatible metal-molybdenum, enabling the realization of ferroelectric nitride semiconductors on polycrystalline molybdenum. Robust and wake-up-free ferroelectricity has been measured in the epitaxially grown ScAlN directly on metal, and a ferroelectric GaN/ScAlN heterostructure for synaptic memristor has been proposed and demonstrated, showing potential applications in neuromorphic computing.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Ding Wang, Ping Wang, Shubham Mondal, Mingtao Hu, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: Computing in the analog regime using nonlinear ferroelectric resistive memory arrays can potentially alleviate the energy constraints and complexity/footprint challenges imposed by digital von Neumann systems. In this study, ferroelectric and analog resistive switching in an epitaxial nitride heterojunction comprised of ultrathin nitride ferroelectrics, specifically ScAlN, has been demonstrated. The results show high ON/OFF ratios, uniformity, retention, and cycling endurance, along with the capability for multistate operation and image processing.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Yuanpeng Wu, Ping Wang, Woncheol Lee, Anthony Aiello, Parag Deotare, Theodore Norris, Pallab Bhattacharya, Mackillo Kira, Emmanouil Kioupakis, Zetian Mi
Summary: Both 2D TMDs and III-V semiconductors are potential platforms for quantum technology, but each with its limitations. 2D TMDs have a large exciton binding energy and customizable quantum properties, but compatibility issues with existing industrial processes. On the other hand, III-nitrides have been widely used in light-emitting devices and power electronics but lack exploitation of excitonic quantum aspects. Recent advancements in 2D III-nitrides have shown promise in achieving room-temperature quantum technologies.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Ayush Pandey, Yixin Xiao, Maddaka Reddeppa, Yakshita Malhotra, Jiangnan Liu, Jungwook Min, Yuanpeng Wu, Zetian Mi
Summary: Efforts are being made to develop efficient micrometer-scale LEDs for future display technologies, but their efficiency remains lower than conventional broad-area devices. This study emphasizes the importance of p-doping in microLEDs for achieving high efficiency performance in nanostructure-based devices.
APPLIED PHYSICS LETTERS
(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
Materials Science, Multidisciplinary
Chuanyu Jia, Chunliang Shen, Qi Wang
Summary: The carrier-transport properties of InGaN red LED with V-pits layer and step-graded GaN barrier were investigated. The use of V-pits layer inhibits the lateral diffusion of electrons, improves the uniformity of holes concentration distribution, and reduces non-radiative recombination rate. The adoption of step gradient GaN barrier improves the injection efficiency of holes and alleviates the efficiency droop.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Tongtong Zhang, Lingzhi Wang, Jing Wang, Zhongqiang Wang, Madhav Gupta, Xuyun Guo, Ye Zhu, Yau Chuen Yiu, Tony K. C. Hui, Yan Zhou, Can Li, Dangyuan Lei, Kwai Hei Li, Xinqiang Wang, Qi Wang, Lei Shao, Zhiqin Chu
Summary: The authors demonstrate the growth of robust and stable chaotic pattern of diamond microparticles containing SiV defects on silicon substrates. These microparticles can be used as anti-counterfeiting labels with high-capacity optical encoding and ultrahigh stability in extreme application scenarios. They can be practically applied in diverse fields immediately.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Mathematical
Wenjian Zheng, An Chang, Qi Wang, Jianing Shang, Mandi Cui
Summary: The correlation filtering algorithm is used to track dim and small targets in real time, improving accuracy. After denoising, a model is constructed using infrared small and weak target image data, and the brightness value and position of unknown targets are obtained. The joint probabilistic data association algorithm and particle filter are used for real-time tracking, achieving good accuracy. The algorithm reduces tracking deviation and is less affected by environmental factors.
ADVANCES IN MATHEMATICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Xixi Yin, Lang Zhou, Qi Wang, Yangfang Liao, Bing Lv
Summary: Using the first-principles method and Boltzmann transport theory, this paper systematically studies the electronic and phonon transport properties of two-dimensional TlInSe3. The results show that 2D TlInSe3 has excellent power factor and ultra-low lattice thermal conductivity due to low phonon group velocity and strong anharmonicity. Furthermore, the analysis reveals that 2D TlInSe3 exhibits a high ZT value as a potential TE material. These findings contribute to the exploration of new TE materials.
FRONTIERS IN PHYSICS
(2023)
Article
Chemistry, Analytical
Samadrita Das, Trupti Ranjan Lenka, Fazal Ahmed Talukdar, Hieu Pham Trung Nguyen, Giovanni Crupi
Summary: In this study, a novel structure of AlGaN UV LED with polarization-engineered heart-shaped AlGaN quantum barriers was proposed to address the issue of electron leakage. By decreasing the downward band bending and flattening the electrostatic field, significant improvements in electroluminescence, optical output power, and efficiency were achieved. This new EBL-free AlGaN LED shows great potential in enhancing optical power and producing highly efficient UV emitters.
