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In situ Etching of β-Ga2O3 using tert-Butyl Chloride in an MOCVD System

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arXiv 2024年

作者： Gorsak, Cameron A. Bowman, Henry J. Gann, Katie R. Smith, Kathleen T. Steele, Jacob Jena, Debdeep Schlom, Darrell G. Xing, Huili Grace Thompson, Michael O. Nair, Hari P. Department of Materials Science and Engineering Cornell University IthacaNY14853 United States PARADIM REU Cornell University IthacaNY14853 United States School of Applied and Engineering Physics Cornell University IthacaNY14853 United States School of Electrical and Computer Engineering Cornell University IthacaNY14853 United States Kavli Institute Cornell for Nanoscale Science Cornell University IthacaNY14853 United States Leibniz-Institut für Kristallzüchtung Max-Born-Str. 2 Berlin12489 Germany

In this study, we investigate in situ etching of β-Ga2O3 in a metal-organic chemical vapor deposition (MOCVD) system using tert-Butyl chloride (TBCl). We report the successful etching of both heteroepitaxial (2̅01)-oriented and homoepitaxial (010)-oriented β-Ga2O3 films over a wide range of substrate temperature, TBCl molar flows, and reactor pressures. We identify that the likely etchant is HCl (g) formed by the pyrolysis of TBCl in the hydrodynamic boundary layer above the substrate. The temperature dependence of the etch rate reveals two distinct regimes characterized by markedly different apparent activation energies. The extracted apparent activation energies suggest that at temperatures below ~800 °C the etch rate is likely limited by desorption of etch products, while at higher substrate temperatures chemisorption of HCl limits the etch rate. The relative etch rates of heteroepitaxial (2̅01) and homoepitaxial (010) β-Ga2O3 were observed to scale by the ratio of the surface energies indicating an anisotropic etch. For (010) homoepitaxial films, relatively smooth post-etch surface morphology was achieved by tuning the etching parameters. © 2024, CC BY.

关键词： Activation energy

Can QR Codes be used to readout Colorimetric Gas Sensors? A Back-Compatible Color QR Code with an Embedded CO2 Sensor Dye

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Can QR Codes be used to readout Colorimetric Gas Sensors? A ...

IEEE SENSORS

作者： Ismael Benito-Altamirano Laura Engel Ferran Crugeira Miriam Marchena Cristian Fàbrega Jürgen Wöllenstein J. Daniel Prades Department of Electronics and Biomedical Engineering MIND/IN2UB Universitat De Barcelona Barcelona Spain eHealth Center Faculty of Computer Science Multimedia and Telecommunications Universitat Oberta de Catalunya Barcelona Spain Fraunhofer Institute for Physical Measurement Techniques IPM Freiburg Germany Department of Microsystems Engineering-IMTEK University of Freiburg Freiburg Germany Department of Chemistry Universitat Autonoma de Barcelona Bellaterra Spain ColorSensing Barcelona Spain Laboratory for Emerging Nanometrology (LENA) Institute of Semiconductor Technology (IHT) Technische Universität Braunschweig Braunschweig Germany

ISBN: (数字)9798350363517

ISBN: (纸本)9798350363524

Colorimetric dye readout devices have been explored extensively, with many approaches relying on complex hardware setups that stabilize the illuminant and capture conditions, typically involving attachments to smartphones or other digital cameras. In this work, we introduce a cost-effective sensor fabrication pipeline to embed a colorimetric dye in a QR Code, enabling readout by any standard smartphone without the need for specialized equipment. QR Codes, as established machine- readable patterns, offer a robust platform for integrating gasometric active dyes. Our approach ensures the preservation of QR Code data integrity by employing a novel method for maintaining back-compatibility throughout the pattern creation process, avoiding the limitations of dye placement solely in the center or outside the QR Code. We demonstrate this concept by embedding a CO2 sensor dye in a QR Code, while the QR Code presents a link to our website and a traceability ID. The dye is based on a pH-sensitive dye that changes color in the presence of CO2, focused on Modified Atmosphere Packaging (MAP) applications.

关键词： Systematics Image color analysis Pipelines Thumb QR codes Color Digital cameras Splines (mathematics) Smart phones Standards

Morphological Effects on the Performance of Broadband Organic Photomultiplication Photodetectors Containing Selenium Substituted Non-Fullerene Acceptors

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Advanced Functional Materials 2023年第32期33卷 2301538-2301538页

作者： Suthar, Gajendra Hsiao, Yu-Tang Tsai, Kuen-Wei Liao, Chuang-Yi Chu, Chih-Wei Chang, Yi-Ming Chen, Fang-Chung Department of Photonics College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Raynergy Tek Incorporation 2F 60 Park Ave. 2 Hsinchu Science Park Hsinchu30844 Taiwan Research Center for Applied Sciences Academia Sinica Taipei11529 Taiwan Center for Emergent Functional Matter Science National Yang Ming Chiao Tung University Hsinchu30010 Taiwan

Organic photodetectors (OPDs) with spectral response extending from ultraviolet to near-infrared domains are of great interest for many applications. Morphological impact on the performance of photomultiplication (PM)-type OPDs, however, is still rarely investigated so far. Herein, a non-fullerene acceptor, Y6-Se-HD, is synthesized, in which heavier selenium atoms substitute the sulfur atoms in the core of Y6, and used for fabricating PM-OPDs. The resulting devices exhibit remarkable PM effects in a very broadband spectral range covering from 320 to 1090 nm. A maximum EQE value of ≈6500% at 860 nm is achieved at a low bias of −1.0 V. As compared with the device prepared with Y6 molecules, the Y6-Se-HD OPDs exhibited much enhanced performance. From the morphological analysis, we infer that Y6-Se-HD almost covers the entire active layer and avoids the direct contact of the hole-trapping donor polymers with the Ag electrode, thereby resulting in stronger charge trapping and preventing possible charge recombination and/or quenching. Furthermore, finer phase separation between the donor and acceptor molecules also facilitates hole trapping and strengthens the PM effects. This research highlights the importance of morphological effects on the PM-OPDs and demonstrates one approach for controlling the device morphology. © 2023 Wiley-VCH GmbH.

关键词： Fullerenes

Semantic Clustering based Deduction Learning for Image Recognition and Classification

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arXiv 2021年

作者： Ma, Wenchi Tu, Xuemin Luo, Bo Wang, Guanghui The Department of Electrical Engineering and Computer Science The University of Kansas LawrenceKS66045 United States The Department of Mathematics The University of Kansas LawrenceKS66045 United States The Department of Computer Science Ryerson University TorontoONM5B 2K3 Canada

The paper proposes a semantic clustering based deduction learning by mimicking the learning and thinking process of human brains. Human beings can make judgments based on experience and cognition, and as a result, no one would recognize an unknown animal as a car. Inspired by this observation, we propose to train deep learning models using the clustering prior that can guide the models to learn with the ability of semantic deducing and summarizing from classification attributes, such as a cat belonging to animals while a car pertaining to vehicles. The proposed approach realizes the high-level clustering in the semantic space, enabling the model to deduce the relations among various classes during the learning process. In addition, the paper introduces a semantic prior based random search for the opposite labels to ensure the smooth distribution of the clustering and the robustness of the classifiers. The proposed approach is supported theoretically and empirically through extensive experiments. We compare the performance across state-of-the-art classifiers on popular benchmarks, and the generalization ability is verified by adding noisy labeling to the datasets. Experimental results demonstrate the superiority of the proposed approach. © 2021, CC BY.

关键词： Semantics

Gamma-Ray Burst Light Curve Reconstruction: A Comparative Machine and Deep Learning Analysis

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arXiv 2024年

作者： Kaushal, A. Manchanda, A. Dainotti, M.G. Deepu, A. Naqi, S. Felix, J. Indoriya, N. Magesh, S.P. Gupta, H. Gupta, K. Madhan, A. Hartmann, D.H. Pollo, A. Bogdan, M. Prochaska, J.X. Fraija, N. Debnath, D. Department of Computer Science and Engineering UIET-H Panjab University Punjab 146001 India Department of Physics Indian Institute of Technology Telangana Hyderabad502284 India National Astronomical Observatory of Japan 2 Chome-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Astronomical Sciences The Graduate University for Advanced Studies SOKENDAI Shonankokusaimura Miura District Kanagawa Hayama240-0115 Japan Nevada Center for Astrophysics University of Nevada 4505 Maryland Parkway Las VegasNV89154 United States Space Science Institute 4765 Walnut Street Suite B BoulderCO80301 United States Department of Ocean Engineering and Naval Architecture Indian Institute of Technology West Bengal Kharagpur721302 India KNIT Uttar Pradesh Sultanpur228118 India Indian Institute of Technology Kharagpur721302 India Department of Electrical Engineering and Computer Science IISER Madhya Pradesh Bhopal462066 India Indian Institute of Technology Madras600036 India MIT WPU School of Computer Science & Engineering Pune411038 India Department of Computer Science PSIT College Uttar Pradesh Kanpur209305 India Visveswaraya Technological University Karnataka Belagavi590018 India Department of Physics and Astronomy Clemson University ClemsonSC29634 United States Astronomical Observatory of Jagiellonian University in Kraków Orla 171 Kraków30-244 Poland National Centre for Nuclear Research Warsaw02-093 Poland Department of Mathematics University of Wroclaw Wroclaw50-384 Poland University of California Santa Cruz 1156 High Street Santa CruzCA95064 United States National Autonoma University of Mexico Circuito Interior Mexico City04510 Mexico NIT Tripura Agartala799046 India

Gamma-Ray Bursts (GRBs), observed at large redshifts, are probes of the evolution of the Universe and can be used as cosmological tools. To this end, we need tight (with small dispersion) correlations among key parameters. To reduce such a dispersion, we will mitigate gaps in light curves (LCs), including the plateau region, key to building the two-dimensional Dainotti relation between the end time of plateau emission (Ta) to its luminosity (La). We reconstruct LCs using nine models: Multi-Layer Perceptron (MLP), Bi-Mamba, Fourier Transform, Gaussian Process–Random Forest Hybrid (GP-RF), Bidirectional Long Short-Term Memory (Bi-LSTM), Conditional GAN (CGAN), SARIMAX-based Kalman filter, Kolmogorov–Arnold Networks (KANs), and Attention U-Net. These methods are compared to the Willingale model (W07) over a sample of 545 GRBs. MLP and Bi-Mamba outperform other methods, with MLP reducing the plateau parameter uncertainties by 25.9% for log Ta, 28.6% for log Fa, and 37.7% for α (the post-plateau slope in the W07 model), achieving the lowest 5-fold cross validation (CV) mean squared error (MSE) of 0.0275. Bi-Mamba achieved the lowest uncertainty of parameters, a 33.3% reduction in log Ta and log Fa and a 41.9% in α, but with a higher MSE of 0.130. Bi-Mamba brings the lowest outlier percentage for log Ta and log Fa (2.70%), while MLP carry α outliers to 0.900%. The other methods yield MSE values ranging from 0.0339 to 0.174. These improvements in parameter precision are needed to use GRBs as standard candles, investigate theoretical models, and predict GRB redshifts through machine learning. Copyright © 2024, The Authors. All rights reserved.

关键词： Mean square error

Structure, magnetic properties, and cycloidal spin ordering in Nd-doped BiFeO3 synthesized by sol-gel method

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arXiv 2024年

作者： Komędera, K. Siedliska, K. Gondek, L. Nalecz, D.M. Panek, R. Krupska-Klimczak, M. Jankowska-Sumara, I. Tokarz, W. Tabiś, W. Pikula, T. Faculty of Physics and Applied Computer Science AGH University of Krakow Mickiewicza 30 Kraków30-059 Poland Mössbauer Spectroscopy Laboratory University of National Education Commission Podchorążych 2 Kraków30-084 Poland Department of Electronics and Information Technologies Lublin University of Technology Nadbystrzycka 38A Lublin20-618 Poland Institute of Art and Design University of the National Education Commission Podchorążych 2 Kraków30-084 Poland Department of Construction Materials Engineering and Geoengineering Lublin University of Technology Nadbystrzycka 40 Lublin20-618 Poland Institute of Security Studies and Computer Science University of the National Education Commission Podchorążych 2 Kraków30-084 Poland Department of Exact and Natural Sciences University of the National Education Commission Podchorążych 2 Kraków30-084 Poland Institute of Solid State Physics TU Wien Vienna1040 Austria

In this study the structural and magnetic properties of Nd-doped BiFeO3 materials with the formula Bi1-xNdxFeO3 (x = 0–0.2) were investigated. Samples were prepared using the sol-gel method and annealed at 823 K for 4 hours. Microstructural studies indicated that nanomaterials with an average grain size of less than 100 nm were produced, with the smallest grain size observed for the solid solution with x = 0.15. Rietveld analysis of diffraction patterns revealed a composition-driven transformation from the rhombohedral (R3c) lattice to the orthorhombic (Pbam) structure. The above finding is correlated to Mössbauer spectroscopy data, which demonstrated the gradual destruction of the spin cycloid due to the structural transformation to the Pbam structure. The spectra were analyzed using a complex hyperfine magnetic field distribution model reflecting cycloidal spin ordering. Scanning differential calorimetry revealed that for the investigated materials the magnetic ordering temperatures are close to 640 K, independently from the Nd concentration. Magnetic measurements showed the emergence of weak ferromagnetic properties with increasing Nd ions concentration, consistently with Mössbauer spectroscopy data. © 2024, CC BY.

关键词： Sol-gel process

ACHIEVING WELL-INFORMED DECISION-MAKING IN DRUG DISCOVERY: A COMPREHENSIVE CALIBRATION STUDY USING NEURAL NETWORK-BASED STRUCTURE-ACTIVITY MODELS

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arXiv 2024年

作者： Friesacher, Hannah Rosa Engkvist, Ola Mervin, Lewis Moreau, Yves Arany, Adam ESAT STADIUS KU Leuven Leuven3000 Belgium Molecular AI Discovery Sciences R&D AstraZeneca Gothenburg Gothenburg 431 83 Sweden Molecular AI Discovery Sciences R&D AstraZeneca Cambridge CambridgeCB2 0AA United Kingdom Department of Computer Science and Engineering Chalmers University of Technology Gothenburg412 96 Sweden

In the drug discovery process, where experiments can be costly and time-consuming, computational models that predict drug-target interactions are valuable tools to accelerate the development of new therapeutic agents. Estimating the uncertainty inherent in these neural network predictions provides valuable information that facilitates optimal decision-making when risk assessment is crucial. However, such models can be poorly calibrated, which results in unreliable uncertainty estimates that do not reflect the true predictive uncertainty. In this study, we compare different metrics, including accuracy and calibration scores, used for model hyperparameter tuning to investigate which model selection strategy achieves well-calibrated models. Furthermore, we propose to use a computationally efficient Bayesian uncertainty estimation method named Bayesian Linear Probing (BLP), which generates Hamiltonian Monte Carlo (HMC) trajectories to obtain samples for the parameters of a Bayesian Logistic Regression fitted to the hidden layer of the baseline neural network. We report that BLP improves model calibration and achieves the performance of common uncertainty quantification methods by combining the benefits of uncertainty estimation and probability calibration methods. Finally, we show that combining post hoc calibration method with well-performing uncertainty quantification approaches can boost model accuracy and calibration. Copyright © 2024, The Authors. All rights reserved.

关键词： Risk assessment

n-ary Isolation Forest: An Experimental Comparative Analysis 19th

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n-ary Isolation Forest: An Experimental Comparative Analysis

19th International Conference on Artificial Intelligence and Soft Computing, ICAISC 2020

作者： Karczmarek, Pawel Kiersztyn, Adam Pedrycz, Witold Department of Computer Science Lublin University of Technology ul. Nadbystrzycka 36B Lublin20-618 Poland Department of Electrical and Computer Engineering University of Alberta EdmontonABT6R 2V4 Canada Department of Electrical and Computer Engineering Faculty of Engineering King Abdulaziz University Jeddah21589 Saudi Arabia Systems Research Institute Polish Academy of Sciences Warsaw Poland

ISBN: (纸本)9783030615338

One of the most challenging problems of modern data mining and Computational Intelligence society has been the task of anomaly detection in large datasets, particularly containing mixed data, namely categorical, spatial, or spatio-temporal. In this study, we discuss various versions of the well-known Isolation Forest method as a efficient tool for finding outliers or anomalies. The versions are based on binary, ternary, etc. search trees. Traditional Isolation Forest is based on searching binary search trees. We build and investigate n-ary search trees and analyze their efficiency in the context of anomaly detection. © 2020, Springer Nature Switzerland AG.

关键词： Anomaly detection

Optically-Sampled Superconducting-Nanostrip Photon-Number Resolving Detector for Non-Classical Quantum State Generation

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arXiv 2024年

作者： Endo, Mamoru Takahashi, Kazuma Nomura, Takefumi Sonoyama, Tatsuki Yabuno, Masahiro Miki, Shigehito Terai, Hirotaka Kashiwazaki, Takahiro Inoue, Asuka Umeki, Takeshi Nehra, Rajveer Takase, Kan Asavanant, Warit Furusawa, Akira Department of Applied Physics School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-8656 Japan Optical Quantum Computing Research Team RIKEN Center for Quantum Computing 2-1 Hirosawa Saitama Wako351-0198 Japan Advanced ICT Research Institute National Institute of Information and Communications Technology 588-2 Iwaoka Nishi Kobe651-2492 Japan NTT Device Technology Labs NTT Corporation 3-1 Morinosato Wakamiya Kanagawa Atsugi243-0198 Japan Department of Electrical and Computer Engineering University of Massachusetts Amherst AmherstMA01003 United States Department of Physics University of Massachusetts Amherst AmherstMA01003 United States College of Information and Computer Science University of Massachusetts Amherst AmherstMA01003 United States

Photon number-resolving detectors (PNRDs) are the ultimate optical sensors. Superconducting-nanostrip photon detectors (SNSPDs), traditionally known as ON-OFF detectors, have recently been found to have photon number resolving capability without multiplexing. This discovery positions them to become true PNRDs. However, their practical use is limited by the need to precisely detect tiny signal differences with low signal-to-noise ratios within sub-nanosecond time frames. We overcome this challenge using optical sampling with a dual-output Mach Zehnder modulator (DO-MZM) and ultra-short pulsed laser. By adjusting the DO-MZM’s bias voltage to nearly balance the outputs, this method enables sensitive detection of picosecond-order signal differences, achieving a temporal resolution of 1.9 ps and facilitating real-time photon number resolution. We applied this method to produce various non-classical quantum states, enhancing their non-classicality through photon number resolution. This advancement marks a significant shift from principle verification to practical application for SNSPD-type PNRDs in diverse quantum optics fields. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum optics