Article
Physics, Applied
F. Vitale, D. Repp, T. Siefke, U. Zeitner, U. Peschel, T. Pertsch, C. Ronning
Summary: In this study, a mode selection scheme based on distributed feedback was proposed to achieve quasi-single mode lasing action in plasmonic nanowires. The orientation of the nanowire on the grating was found to affect the emission spectrum, with an additional peak emerging when the nano-cavity was perpendicular to the ridge direction. This peak was attributed to a hybrid mode dominating the mode competition and supported by localized plasmon polaritons on the metal grating ridges.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Analytical
Md Ashfaque Hossain Khan, Ratan Debnath, Abhishek Motayed, Mulpuri Rao
Summary: A TiO2-coated GaN nanowire-based back-gate field-effect transistor (FET) device was designed to address the cross-sensitive nature of metal oxides, with a Si back gate and C-AlGaN gate dielectric as tunable parameters to enhance discrimination of gases. The results showed a significant increase in NO2 response with back-gate bias, while SO2 response increased insignificantly, explained by a band diagram based on density functional theory (DFT) molecular models.
Article
Optics
Lars Persson, Filip Hjort, Giulia Cardinali, Johannes Enslin, Tim Kolbe, Tim Wernicke, Michael Kneissl, Joachim Ciers, Asa Haglund
Summary: A concept for achieving a temperature-stable lasing wavelength in VCSELs is proposed and demonstrated. By incorporating a dielectric material with a negative thermo-optic coefficient in the DBRs, the positive dn/dT of the semiconductor cavity can be compensated and the redshift of the lasing wavelength can be avoided. This concept is validated for optically-pumped VCSELs emitting at 310 nm, showing a maximum blueshift of less than 0.1 nm over an 80 degrees C range.
LASER & PHOTONICS REVIEWS
(2023)
Article
Chemistry, Physical
Edgars Butanovs, Kevon Kadiwala, Aleksejs Gopejenko, Dmitry Bocharov, Sergei Piskunov, Boris Polyakov
Summary: In this study, GaNMoS2 and GaN-WS2 core-shell nanowires were successfully synthesized using two different methods. The experimental results were in agreement with theoretical calculations, demonstrating the potential of these core-shell heterostructures as photocatalysts.
APPLIED SURFACE SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Jaebum Sung, Sangyeun Park, Hongyun So
Summary: This study designed and developed a hexahedral UV photodetector using 3D printing technology, which can achieve omnidirectional UV detection. The photodetector has six sensors that can display the current changes of each sensor based on the angle of UV light incidence, making it easy to track the UV source.
IEEE SENSORS JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Long Xu, Yuehan Cao, Tianwei Song, Caixia Xu
Summary: This work investigates the low-threshold resonant lasing emission in undoped and Mg-doped GaN thin films on sapphire substrates with interfacial design. The scattering cross-section of the periodic resonant structure is found to reduce the threshold and enhance the resonant lasing emission. Mg-doped GaN thin films show better lasing emission performance compared to undoped and Si-doped GaN thin films. The lasing energy level system and defect densities play a vital role in the lasing emission.
Article
Nanoscience & Nanotechnology
Yikai Liao, You Jin Kim, Junyu Lai, Jung-Hun Seo, Munho Kim
Summary: Metal-assisted chemical etching (MacEtch) can create GaN nanoridge surfaces on undoped GaN thin films, reducing surface reflection in the UV regime and enhancing photodiode responsivity by 6 times.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Ziyi Zhang, Maki Kushimoto, Akira Yoshikawa, Koji Aoto, Chiaki Sasaoka, Leo J. Schowalter, Hiroshi Amano
Summary: This study investigates the temperature dependence of key parameters and their impact on achieving continuous-wave lasing in AlGaN-based laser diodes at UV-C wavelengths. The reduction in threshold voltage was achieved by tapering the sides of the laser diode mesa and reducing the lateral distance between the n- and p-electrodes. Continuous-wave lasing at room temperature was demonstrated with a threshold current density of 4.2 kA/cm(2) and a threshold voltage of 8.7 V.
APPLIED PHYSICS LETTERS
(2022)
Review
Crystallography
Wannian Fang, Qiang Li, Jiaxing Li, Yuxuan Li, Qifan Zhang, Ransheng Chen, Mingdi Wang, Feng Yun, Tao Wang
Summary: The application of deep ultraviolet detection (DUV) in military and civil fields has gained increasing attention from researchers. Inorganic materials are widely used in DUV detection due to their good stability and controllable growth, compared to the complex molecular structure and poor stability of organic materials. Rapid advances in preparing high-quality ultrawide-bandgap (UWBG) semiconductors have enabled the development of high-performance DUV photodetectors with different geometries, overcoming disadvantages in traditional detectors. This article provides a brief introduction to the development history and types of DUV detectors, and comprehensively summarizes and reviews typical UWBG detection materials and their methods of preparation, as well as their research and application status, including III-nitride semiconductors, gallium oxide, diamond, etc. Additionally, problems related to DUV detection materials, such as material growth, device performance, and future development, are discussed.
Article
Engineering, Electrical & Electronic
Georgios Doundoulakis, Dimitris Pavlidis
Summary: The electrical characteristics of simulated vertical gallium nitride nanowire vacuum field emission diodes and transistors were investigated, showing changes in turn-on voltage, saturation emitter current density, and transfer characteristics depending on geometry and material parameters. Sharp-tip GaN nanowires demonstrated decreased turn-on voltage and increased saturation emitter current density, while sharp-tip VFETs displayed reduced threshold voltage, increased transconductance, and improved ON-/OFF-current ratio compared to flat-tip ones. The output characteristics of both types of devices exhibited nonlinear behavior at low voltage regimes.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Environmental
Yikai Liao, You Jin Kim, Munho Kim
Summary: In this research, a high sensitivity self-powered UV photodetector with low dark current and low power consumption was developed by constructing a heterojunction on a commercially available substrate. The detector exhibited excellent performance with a dark current as low as 0.45 pA, a detectivity of 1.9 x 1013 Jones, and fast response times. This work provides a cost-effective approach for the development of highly sensitive UV detecting devices.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Marissa Granados-Baez, Arunabh Mukherjee, Liangyu Qiu, Chitraleema Chakraborty, A. Nick Vamivakas, Jaime Cardenas
Summary: Recent demonstrations have shown light sources or lasers based on two-dimensional (2D) materials with different photonic cavities emitting into free space. However, on-chip lasing with 2D materials remains challenging. In this study, we characterize on-chip cavity coupled emission from 2D materials and observe laser-like emission properties. We report a 30% linewidth narrowing and a 'kink' in the input vs. output power relation of a device consisting of a monolayer WSe2 integrated with a high-quality factor microring resonator operating at room temperature. Our findings could pave the way for fully integrated devices utilizing 2D materials for on-chip active functionalities.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Materials Science, Multidisciplinary
Nasir Alfaraj, Kuang-Hui Li, Meshal Alawein, Chun Hong Kang, Laurentiu Braic, Nicolae Catalin Zoita, Adrian Emil Kiss, Tien Khee Ng, Boon S. Ooi
Summary: This article investigates the ultrahigh sensitivity and DUV photodetection capability of a hybrid oxide-nitride stack grown heterogeneously on a conductive ceramic crystal. It was found that the growth process of beta-Ga2O3 crystal on TiN introduced additional defects, resulting in DUV photodetectors with true solar-blind characteristics.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Article
Physics, Condensed Matter
Xue Yin, Songrui Zhao
Summary: By growing the AlGaN active layer at a higher temperature, the lasing threshold of the AlGaN/AlN laser has been significantly reduced, with successful control of Al vacancy related point defects demonstrated by the absence of defect emission in the visible band.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Optics
Shuyu Zhao, Binbin Xu, Zhenyu Zhao, Dandan Gu, Yan Zhang, Wenlong Lv, Xueqin Lv
Summary: A novel GaN-based RCLED with single-longitudinal-mode light emission was demonstrated. By adopting a Ta2O5/SiO2 filter-film-structure DBR as the top mirror, the RCLED achieved single-longitudinal-mode emission with a narrow linewidth and exhibited better wavelength stability.
Article
Chemistry, Multidisciplinary
Konthoujam James Singh, Hao-Hsuan Ciou, Ya-Hui Chang, Yen-Shou Lin, Hsiang-Ting Lin, Po-Cheng Tsai, Shih-Yen Lin, Min-Hsiung Shih, Hao-Chung Kuo
Summary: This paper investigates the coupling of excitons in tungsten diselenide monolayer with a one-dimensional photonic crystal at room temperature, and demonstrates the manipulation of circular dichroism and circularly polarized light emissions through the integration of TMDs and photonic crystal. The study holds potential for applications in optical information technology, biosensing, and optoelectronic devices.
Article
Crystallography
Catherine Langpoklakpam, An-Chen Liu, Kuo-Hsiung Chu, Lung-Hsing Hsu, Wen-Chung Lee, Shih-Chen Chen, Chia-Wei Sun, Min-Hsiung Shih, Kung-Yen Lee, Hao-Chung Kuo
Summary: This paper reviews the superior properties of SiC power devices and their applications in various power applications. SiC MOSFETs have been extensively commercialized due to their low on-resistance, reduced switching losses, and high switching speeds.
Article
Multidisciplinary Sciences
Yuan-Fong Chou Chau, Hao-En Chang, Po-Sheng Huang, Pin Chieh Wu, Chee Ming Lim, Li-Ming Chiang, Tzyy-Jiann Wang, Chung-Ting Chou Chao, Tsung Sheng Kao, Min-Hsiung Shih, Hai-Pang Chiang
Summary: This study demonstrates a tunable ferroelectric lithography plasmon-enhanced substrate to generate photo-reduced silver nanoparticles (AgNPs) and achieve enhanced photoluminescence (PL) with shortened lifetime. This effect can be attributed to the localized electromagnetic wave produced by the nanotextured AgNPs layers' surface and gap plasmon resonances.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
Hsiang-Ting Lin, Chiao-Yun Chang, Cheng-Li Yu, Andrew Boyi Lee, Shih-Yu Gu, Li-Syuan Lu, Yu-Wei Zhang, Shih-Yen Lin, Wen-Hao Chang, Shu-Wei Chang, Min-Hsiung Shih
Summary: This study investigates dual-color continuous-wave microcavity lasers by integrating WSe2 monolayer and CdSe quantum dots into a single microdisk cavity. The results show that adding CdSe quantum dots can reduce the laser threshold of WSe2 monolayer and expand the wavelength range of TMDC-based compact lasers.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yuan-Fong Chou Chau, Hao-En Chang, Po-Sheng Huang, Pin Chieh Wu, Tzyy-Jiann Wang, Chung-Ting Chou Chao, Muhammad Raziq Rahimi Kooh, Tsung Sheng Kao, Min-Hsiung Shih, Hai-Pang Chiang
Summary: This work fabricates a plasmonic lithium niobate substrate with metal nanoparticles (MNPs) to enhance photoluminescence and reduce lifetime, and it explores the potential influence of surface plasmon coupling on the photoluminescence reactions.
RESULTS IN PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Ya-Hui Chang, Yen-Shou Lin, Konthoujam James Singh, Hsiang-Ting Lin, Chiao-Yun Chang, Zheng-Zhe Chen, Yu-Wei Zhang, Shih-Yen Lin, Hao-Chung Kuo, Min-Hsiung Shih
Summary: A multicolor AC-driven light-emitting device was developed by integrating a WSe2 monolayer and AlGaInP-GaInP multiple quantum well (MQW) structures. The CVD-grown WSe2 monolayer was placed on top of an AlGaInP-based LED wafer to create a two-dimensional/three-dimensional heterostructure. These hybrid devices expand the wavelength range of 2-D TMDC-based light emitters and support their implementation in various applications.
Article
Chemistry, Multidisciplinary
Shang-Yang Yu, Min-Hsiung Shih, Yun-Cheng Ku, Yi-Han Kuo, Jiunn-Woei Liaw
Summary: A water-immersion laser-scanning annealing method was developed to improve the crystallinity and optical properties of a deposited polycrystalline Au film, resulting in reduced optical losses, increased sensitivity, and improved performance for biosensors.
Article
Nanoscience & Nanotechnology
Po-Cheng Tsai, Coung-Ru Yan, Shoou-Jinn Chang, Shu-Wei Chang, Shih-Yen Lin
Summary: We fabricated top-gate transistors on MoS2 with different layer thicknesses in the source and drain regions using atomic layer etching. The transistor exhibited high and low levels of drain current under forward and reverse gate bias, respectively, at zero gate voltage due to the presence of ALE. The hysteresis loop on the transfer curve indicated the existence of two distinct charge states within a certain range of gate bias, and a long retention time of the charge was observed.
Article
Optics
Chao-Chieh Cheng, Pi-Ju Cheng, Tzu-Wei Huang, Wei-Ting Wang, Jui-Tse Tsai, Min-Hsiung Shih, Shu-Wei Chang
Summary: Optical modes spinning with maximum chirality in chip-level cavities are crucial for quantum and biomedical applications. In this study, the researchers realize circularly-polarized-like lasing modes with maximum chirality at the exceptional point of photonic-crystal one-hole cavities. By improving the reliability of fine-tuning, they achieve robust chirality of the radiation field.
Article
Engineering, Electrical & Electronic
Lucas Yang, Shu-Wei Chang, Chao-Hsin Wu
Summary: This study investigates the electrical characteristics and capture-escape lifetimes of Quantum-well-based heterojunction bipolar light-emitting transistors (HBLETs or LETs) using a steady-state testing method. It provides important knowledge for improving the device modulation bandwidth.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Multidisciplinary
James Singh Konthoujam, Yen-Shou Lin, Yi-Hua Pai, Chiao-Yun Chang, Yu-Wei Zhang, Shih-Yen Lin, Hao-Chung Kuo, Min-Hsiung Shih
Summary: This study reports a significant enhancement in the modulation bandwidth of visible light communication (VLC) by integrating a two-dimensional semiconductor and quantum dots emitter. By integrating a WSe2 monolayer into an Au-nanorod-decorated CdSe/ZnS quantum dots emitter, high modulation performance is achieved. The hybrid quantum dot-gold-tungsten disulfide (QD-Au-WSe2) emitter exhibits a higher modulation bandwidth (130 MHz) compared to pristine quantum dots and a QD-WSe2 heterostructure without Au nanorods (79 and 91 MHz, respectively). The increased transition rate of quantum dot excitons is attributed to the integration of Au nanorods and WSe2 monolayer, which is supported by a reduction in average carrier lifetime observed from time-resolved photoluminescence analysis. This approach and findings provide an opportunity for the application of two-dimensional semiconductors in next-generation miniature VLC devices for high-speed optical communications.
ADVANCED PHOTONICS RESEARCH
(2023)
Article
Engineering, Electrical & Electronic
Mukul Kumar, Lu-Ching Hsueh, Sheng-Wen Cheng, Shu-Wei Chang, Chao-Hsin Wu
Summary: We developed an analytical model to determine the current gain of HBLETs with MQWs inserted into the base. Our model provides insights into the transistor's operation and aids in designing an efficient epi-layer structure. The current gain decreases as the number of QWs in the base increases, but increases when the QW is placed near the collector. The number and position of QWs affect charge capture and ultimately impact the transistor's current gain. We verified our model using experimental data and layer structure designs.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Optics
Guan-Hong Li, Chieh Huang, Feng-Jung Kao, Min-Hsiung Shih, Hao-Chung Kuo, Yi-Jen Chiu, Chao-Kuei Lee
Summary: In this study, supercontinuum generation from 645.3 nm to 851 nm was demonstrated by using a high-order mode and engineering the dispersion within the high nonlinear refractive index material Ta2O5 waveguide. The results show clear potential for applications.
OPTICS AND LASER TECHNOLOGY
(2024)
Article
Nanoscience & Nanotechnology
James Singh Konthoujam, Yen-Shou Lin, Ya-Hui Chang, Hsiang-Ting Lin, Chiao-Yun Chang, Yu-Wei Zhang, Shih-Yen Lin, Hao-Chung Kuo, Min-Hsiung Shih
Summary: We developed a dual-color AC-driven light-emitting device by integrating WSe2 monolayer and AlGaInP-GaInP multiple quantum well structures with an AlOx insulating layer as a capacitor structure. We investigated the device characteristics using an equivalent RC circuit model and analyzed the time-resolved electroluminescence to understand the underlying physical mechanisms. This dual-color hybrid device expands the applications of 2-D TMDC-based light emitters.
Article
Chemistry, Multidisciplinary
Hsiang-Ting Lin, Yao-Yu Hsu, Pi-Ju Cheng, Wei-Ting Wang, Shu-Wei Chang, Min-Hsiung Shih
Summary: In this study, in situ optical chirality tunable nanorod trimer metasurfaces were demonstrated, which could control the degree of circular polarization of transmitted wave by adjusting the gap distances between nanorods and the manipulation of localized surface plasmon resonance (LSPR) coupling. These fabricated chiral metasurfaces can be used as important elements for chip-scale flexible optoelectronic integrated circuits in sensing, display, and communication applications.
NANOSCALE ADVANCES
(2022)