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Comprehensive study of formaldehyde gas sensing performance of a GTO thin film incorporated with gold nanoparticles

Sensors and Actuators B: Chemical 2024年 398卷

作者： Luo, Kai-Hong Liu, I.-P. Chiu, Chao-Chun Lin, Kun-Wei Hsu, Wei-Chou Liu, Wen-Chau Institue of Microelectronics Department of Electrical Engineering National Cheng-Kung University 1 University Road Tainan City70101 Taiwan Department of Material Technology Green Technology Research Institute CPC Corporation No.2 Tso-Nan Road Kaohsiung City81126 Taiwan Department of Computer Science and Information Engineering Chaoyang University of Technology Taichung41349 Taiwan Institute of Microelectronics Department of Electrical Engineering Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng-Kung University Tainan70101 Taiwan

There are lots of semiconducting metal oxides (SMOs) which have been used for detecting volatile organic compounds (VOCs), such as ZnO, SnO2, NiO, Ga2O3, WO3, ZnO, In2O3, etc. SnO2 is a widespread used SMO to develop a variety of chip to detect VOCs. In this work, a novel SMO gas sensor based on the combination of SnO2 material with a little proportion of wide bandgap (4.9 eV) Ga2O3 material denoted as GTO, is proposed to detect formaldehyde (HCHO) gas. The studied sensor is synthesized by a radio-frequency (RF) sputtered GTO thin film and vacuum thermal evaporated gold (Au) nanoparticles (NPs) and treated with a post annealing. The related material properties are analyzed by X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), high-resolution scanning electron microscopy (HRSEM), and transmission electron microscopy (TEM). The decoration of Au NPs on the surface of GTO thin film causes a significant improvement on sensing performance. A high sensing response of 275 accompanied with a response (recovery) time of 16 s (11 s) under 20 ppm HCHO/air ambiance and an extremely low content of 50 ppb HCHO/air with a sensing response of 21 are obtained at 300 ℃. Furthermore, the studied sensor performs good selectivity, repetitivity, and long-term (120 days) stability. © 2023 Elsevier B.V.

关键词： Thin films

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Radical-Mediated Oxidative Desulfurization of Dibenzothiophene in a Chromophore-Enhanced Photocatalytic System

SSRN

引用

SSRN 2024年

作者： Park, Jihee Yi, Jaeseon Kim, Sujeong Moon, Gun-Hee Choi, Wonyong Department of Electrical and Computer Engineering Seoul National University Seoul08826 Korea Republic of School of Environmental Science and Engineering Pohang University of Science and Technology Pohang37673 Korea Republic of Material Technology Team Samsung Electronics Co. Hwaseong-si18448 Korea Republic of Seoul02792 Korea Republic of Daejeon34113 Korea Republic of Naju58330 Korea Republic of

This research presents a refined photocatalytic oxidative desulfurization (PODS) approach, leveraging a chromophore-enhanced system specifically designed for the selective degradation of dibenzothiophene (DBT). Employing a ruthenium-based sensitizer (RuL) activated by visible light, the system catalytically decomposes peroxydisulfate (S2O2−) into highly reactive radical species, key agents in facilitating efficient sulfur oxidation. This oxidative pathway transforms DBT sequentially into its sulfoxide (DBT-O) and sulfone (DBT-O2) derivatives, achieving nearly complete conversion to DBT-O2. The electron transfer dynamics within this photocatalytic system are rigorously examined through a concentration-dependent decrease in photoluminescence. Additionally, the influences of electron donors and acceptors, along with variations in the sensitizer structure on the system’s activity, are explored. Comparative assessments with a 9,10-dicyanoanthracene (DCA)-sensitized system reveal the superior efficiency and selectivity of sulfate and/or hydroxyl radicals over the superoxide generated in alternative setups. The RuL/S2O82− system exhibits markedly enhanced kinetics for DBT degradation, offering an effective alternative for sulfur removal under milder operational conditions, thus eliminating the need for hydrogen. © 2024, The Authors. All rights reserved.

关键词： Chromophores

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Ultrathin-shell epitaxial Ag@Au core-shell nanowires for high-performance and chemically-stable electronic, optical, and mechanical devices

引用

Nano Research 2021年第11期14卷 4294-4303页

作者： Yangzhi Zhu Sanggon Kim Xuezhi Ma Peter Byrley Ning Yu Qiushi Liu Xiaoming Sun Da Xu Sangshan Peng Martin C.Hartel Shiming Zhang Vadim Jucaud Mehmet R.Dokmeci Ali Khademhosseini Ruoxue Yan Department of Chemical and Environmental Engineering Bourns College of EngineeringUniversity of California-RiversideRiversideCA92521USA Terasaki Institute for Biomedical Innovation Los AngelesCA90064USA Department of Electrical and Computer Engineering University of California-RiversideRiversideCA92521USA State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha410082China Department of Bioengineering University of California-Los AngelesLos AngelesCA90095USA Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina Material Science and Engineering Program University of California-RiversideRiversideCA92521USA

Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.

关键词： epitaxial growth core-shell nanowire plasmonic waveguides atomic force microscopy(AFM)probe transparent electrode wearable electronics

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Measurement of Spin-Polarized Photoemission from Wurtzite and Zinc-Blende Gallium Nitride Photocathodes

arXiv

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arXiv 2024年

作者： Levenson, S.J. Andorf, M.B. Dickensheets, B.D. Bazarov, I.V. Galdi, A. Encomendero, J. Protasenko, V.V. Jena, D. Xing, H.G. Maxson, J.M. Cornell University IthacaNY14850 United States Department of Industrial Engineering University of Salerno SA Fisciano84084 Italy School of Electrical and Computer Engineering Cornell University IthacaNY14853 United States Department of Material Science and Engineering Cornell University IthacaNY14583 United States Kavli Institute Cornell for Nanoscale Science Cornell University IthacaNY14583 United States

Spin-polarized photoemission from wurtzite and zinc-blende gallium nitride (GaN) photocathodes has been observed and measured for the first time. The p-doped GaN photocathodes were epitaxially grown and activated to negative electron affinity (NEA) with a cesium monolayer deposited on their surfaces. A field-retarding Mott polarimeter was used to measure the spin-polarization of electrons photoemitted from the top of the valence band. A spectral scan with a tunable optical parametric amplifier (OPA) constructed to provide low-bandwidth light revealed peak spin polarizations of 17% and 29% in the wurtzite and zinc-blende photocathodes, respectively. Zinc-blende GaN results are analyzed with a spin-polarization model accounting for experimental parameters used in the measurements, while possible mechanisms influencing the obtained spin polarization values of wurtzite GaN are discussed. © 2024, CC BY.

关键词： Photocathodes

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Self-Trapped Exciton in One-Dimensional CsCu2I3 Nanowires

Self-Trapped Exciton in One-Dimensional CsCu2I3 Nanowires

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Xinxin Xing Tian Tong Mohammadjavad Mohebinia Zhiming Wang Jiming Bao Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu China Department of Electrical & Computer Engineering University of Houston Houston TX USA Material Science and Engineering University of Houston Houston TX USA

Low-dimensional CsCu 2 I 3 perovskite has recently attracted extensive attention for its unique structure and photoelectric properties. We demonstrate a detailed spectroscopy study of its self-trapped exciton emissio... 详细信息

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

关键词： Spectroscopy Excitons Lasers and electrooptics Perovskites Laser excitation Nanowires Electrooptical waveguides

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Non-Hermitian selective thermal emitter for thermophotovoltaics

Non-Hermitian selective thermal emitter for thermophotovolta...

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Ciril S. Prasad Samuel C. Raphaelson Gururaj V. Naik Department of Electrical and Computer Engineering Rice University Houston TX USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Department of Material Science and NanoEngineering Rice University Houston TX USA

Selective thermal emitters can boost the efficiency of heat-to-electricity conversion in thermophotovoltaic systems only if their spectral selectivity is high. We demonstrate a non-Hermitian metasurface-based selectiv... 详细信息

ISBN: (纸本)9781957171258

关键词： Emissivity Light intensity Optical constants Silicon Temperature Thermal emission

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electrically Injected mid-infrared GeSn laser on Si operating at 140 K

arXiv

引用

arXiv 2024年

作者： Acharya, Sudip Stanchu, Hryhorii Kumar, Rajesh Ojo, Solomon Benamara, Mourad Chang, Guo-En Li, Baohua Du, Wei Yu, Shui-Qing Material Science and Engineering University of Arkansas FayettevilleAR72701 United States Department of Electrical Engineering and Computer Science University of Arkansas FayettevilleAR72701 United States The Institute for Nanoscience and Engineering University of Arkansas FayettevilleAR72701 United States Department of Mechanical Engineering National Chung Cheng University Chia-Yi County 62102 Taiwan Arktonics LLC 1339 South Pinnacle Drive FayettevilleAR72701 United States

Owing to its true direct bandgap and tunable bandgap energies, GeSn alloys are increasingly attractive as gain media for mid-IR lasers that can be monolithically integrated on Si. Demonstrations of optically pumped GeSn laser operating at room temperature under pulsed excitation and at cryogenic temperature under continuous-wave excitation show great promise of GeSn lasers to be efficient electrically injected light sources on Si. Here we report electrically injected GeSn lasers using Fabry-Perot cavity with 20 µm, 40 µm, and 80 µm ridge widths. A lasing threshold of 0.756 kA/cm2 at 77 K, emitting wavelength of 2722 nm, and maximum operating temperature of 140 K were obtained. The lower threshold current density compared to previous works was achieved by reducing optical loss and improving the optical confinement. The peak power was measured as 2.2 mW/facet at 77 K. © 2024, CC0.

关键词： Energy gap

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Spectral Measurement of the Breakdown Limit of β−Ga2O3 and Tunnel Ionization of Self-Trapped Excitons and Holes

引用

Physical Review Applied 2021年第3期16卷 034011-034011页

作者： Md. Mohsinur Rahman Adnan Darpan Verma Zhanbo Xia Nidhin Kurian Kalarickal Siddharth Rajan Roberto C. Myers Department of Electrical and Computer Engineering The Ohio State University Columbus Ohio 43210 USA Department of Material Science and Engineering The Ohio State University Columbus Ohio 43210 USA

Owing to its strong ionic character coupled with a light electron effective mass, β−Ga2O3 is an unusual semiconductor where large electric fields (approximately 1–6 MV/cm) can be applied while still maintaining a dominant excitonic absorption peak below its ultrawide band gap (Eg ∼ 4.6–4.99 eV). This provides a rare opportunity in the solid state to examine exciton and carrier self-trapping dynamics in the strong-field limit at steady state. Under sub-band-gap photon excitation, we observe a field-induced redshift of the spectral photocurrent peak associated with exciton absorption and a thresholdlike increase in peak amplitude at high field associated with self-trapped hole ionization. The field-dependent spectral response is quantitatively fitted with an exciton-modified Franz-Keldysh effect model, which includes the electric-field-dependent exciton-binding energy due to the quadratic Stark effect. Saturation of the spectral redshift with reverse bias is observed exactly at the onset of dielectric breakdown, providing a spectral means to detect and quantify the local electric field and dielectric breakdown behavior in β−Ga2O3. Additionally, the field-dependent responsivity provides an insight into the photocurrent-production pathway, revealing the photocurrent contributions of self-trapped excitons (STXs) and self-trapped holes (STHs) in β−Ga2O3. Photocurrent and p-type transport in β−Ga2O3 are quantitatively explained by field-dependent tunnel ionization of excitons and self-trapped holes. We employ a quantum-mechanical model of the field-dependent tunnel ionization of STXs and STHs in β−Ga2O3 to model the nonlinear field dependence of the photocurrent amplitude. Fitting to the data, we estimate an effective mass of valence-band holes (18.8m0) and an ultrafast self-trapping time of holes (0.045 fs). This indicates that minority-hole transport in β−Ga2O3 can only arise through tunnel ionization of STHs under strong fields.

关键词： Electric field effects Electronic excitation & ionization Excitons Optoelectronics Stark effect Transparent conducting oxides Wide band gap systems Photoexcitation

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Machine Learning Applications in Spine Biomechanics

arXiv

引用

arXiv 2024年

作者： Ghezelbash, Farshid Eskandari, Amir Hossein Robert-Lachaine, Xavier Cao, Frank Pesteie, Mehran Qiao, Zhuohua Shirazi-Adl, Aboulfazl Larivière, Christian Division of Applied Mechanics Department of Mechanical Engineering Polytechnique Montréal Canada Institut de Recherche Robert Sauvé en Santé et en Sécurité du Travail Montréal Canada Department of Mechanical Engineering and Material Science Duke University United States Department of Electrical and Computer Engineering University of British Columbia Canada Department of Mechanical Engineering McGill University Canada

Spine biomechanics is at a transformation with the advent and integration of machine learning and computer vision technologies. These novel techniques facilitate the estimation of 3D body shapes, anthropometrics, and kinematics from as simple as a single-camera image, making them more accessible and practical for a diverse range of applications. This study introduces a framework that merges these methodologies with traditional musculoskeletal modeling, enabling comprehensive analysis of spinal biomechanics during complex activities from a single camera. Additionally, we aim to evaluate their performance and limitations in spine biomechanics applications. The real-world applications explored in this study include assessment in workplace lifting, evaluation of whiplash injuries in car accidents, and biomechanical analysis in professional sports. Our results demonstrate potential and limitations of various algorithms in estimating body shape, kinematics, and conducting in-field biomechanical analyses. In industrial settings, the potential to utilize these new technologies for biomechanical risk assessments offers a pathway for preventive measures against back injuries. In sports activities, the proposed framework provides new opportunities for performance optimization, injury prevention, and rehabilitation. The application in forensic domain further underscores the wide-reaching implications of this technology. While certain limitations were identified, particularly in accuracy of predictions, complex interactions, and external load estimation, this study demonstrates their potential for advancement in spine biomechanics, heralding an optimistic future in both research and practical applications. © 2024, CC0.

关键词： Sports

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High-Q, size-independent, and reconfigurable optical antennas via zero-index material dispersion engineering

arXiv

引用

arXiv 2025年

作者： Iyer, Prasad P. Pendharkar, Mihir Agrawal, Anchal Foronda, Humberto Iza, Mike Mishra, Umesh K. Nakamura, Shuji DenBaars, Steven Keller, Stacia Palmstrøm, Chris Schuller, Jon A. Electrical and Computer Engineering Department University of California Santa BarbaraCA United States Material Science and Engineering Department University of California Santa BarbaraCA United States Solid State Lighting and Energy Center University of California Santa BarbaraCA United States Center for Integrated Nanotechnologies Sandia National Lab AlbuquerqueNM United States Materials Science and Engineering department Stanford University StanfordCA United States

Enhancing light-matter interactions at the nanoscale is foundational to nanophotonics, with epsilon-near-zero (ENZ) materials demonstrating significant potential. High-quality (Q) factor resonances maximizing these interactions are typically realized in photonic crystals requiring sub-50 nm precision nanofabrication over large areas, limiting scalability and increasing complexity. Mie resonances offer an alternative but are constrained by low Q-factors due to the scarcity of high refractive index materials, necessitating large refractive index changes for effective resonance switching and limiting dynamic reconfigurability. We overcome these limitations by embedding Mie resonators within ENZ media, thereby enhancing Q-factors, mitigating geometric dispersion and fabrication challenges, and maximizing optical reconfigurability. We introduce three resonator-ENZ configurations: voids in AlN, Ge in SiO2, and intrinsic InSb in doped InSb—spanning from low-loss phononic to lossy plasmonic ENZ modes. Using novel epitaxial regrowth techniques, we achieve significant Q-factor improvements over non-embedded resonators. Notably, an air-based Mie resonator embedded in AlN supports resonant Q-factors exceeding 100, with negligible geometric dispersion across sizes from 800 nm to 2,800 nm. Additionally, we demonstrate dynamic reconfigurability of intrinsic InSb resonators by thermally tuning the ENZ wavelength over a 2 µm range in the mid-infrared (11–16 µm) wavelength regime. These results showcase the potential of Mie reonators embedded in ENZ media for high-fidelity sensors, thermal emitters, and reconfigurable metasurfaces, bridging theoretical predictions with practical applications, advancing the development of dynamic, high-Q optical devices. © 2025, CC BY-NC-SA.

关键词： Q factor measurement

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