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arXiv 2024年

作者： Abbasi, Haris Naeem Lu, Yi Zhou, Jie Wang, Ding Sun, Kai Wang, Ping Gong, Jiarui Liu, Dong Liu, Yang Singh, Ranveer Mi, Zetian Ma, Zhenqiang Department of Electrical and Computer Engineering University of Wisconsin-Madison MadisonWI53706 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Department of Material Science and Engineering University of Michigan Ann Arbor48109 United States

Ultra-wide bandgap (UWBG) materials hold immense potential for high-power RF electronics and deep ultraviolet photonics. Among these, AlxGa1−xN emerges as a promising candidate, offering a tunable bandgap from 3.4 eV (GaN) to 6.2 eV (AlN) and remarkable material characteristics. However, achieving efficient p-type doping in high aluminum composition (Al%) AlGaN remains a formidable challenge. This study presents an alternative approach to address this issue by fabricating a p+Si/n-AlN/n+AlGaN heterojunction structure by following the semiconductor grafting technique. Atomic force microscopy (AFM) analysis revealed that the AlN and the nanomembrane surface exhibited a smooth topography with a roughness of 1.96 nm and 0.545 nm, respectively. High-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirmed a sharp and well-defined Si/AlN interface, with minimal defects and strong chemical bonding, crucial for efficient carrier transport. X-ray photoelectron spectroscopy (XPS) measurements demonstrated a type-I heterojunction with a valence band offset (ΔEv) of 2.73-2.84 eV and a conduction band offset (ΔEc) of 2.22-2.11 eV. The pn diode devices exhibited a linear current-voltage (I-V) characteristic, an ideality factor of 1.92, and a rectification ratio of 3.3 × 104, with a turn-on voltage of 3.9 V, indicating effective p-n heterojunction. Temperature-dependent IV measurements showed stable operation up to 90°*** heterojunction's high-quality interface and electrical performance showcase its potential for advanced AlGaN-based optoelectronic and electronic devices. Copyright © 2024, The Authors. All rights reserved.

关键词： Heterojunctions

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Designing Advanced Aqueous Zinc-Ion Batteries:Principles,Strategies,and Perspectives

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Energy & Environmental materials 2022年第3期5卷 823-851页

作者： Yan Li Zhouhao Wang Yi Cai Mei Er Pam Yingkui Yang Daohong Zhang Ye Wang Shaozhuan Huang Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science South-Central University for NationalitiesWuhan 430074China School of Materials Science and Engineering Nanyang Technological UniversitySingapore Singapore Department of Electrical&Computer Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Singapore Key Laboratory of Material Physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China

Aqueous zinc-ion batteries(AZIBs)are an appealing battery system due to their low cost,intrinsic safety,and environmental-friendliness,while their application is plagued by the obstacles from the cathode,electrolyte,and zinc *** the design principles and strategies toward the optimization of cathode,electrolyte,and zinc anode is crucial for the development of ***,we present a comprehensive analysis of the design principles and promising strategies toward the improvement of ***,the various reaction mechanisms are summarized and the existing issues associated with the cathode,electrolyte,and zinc anode are discussed to guide the rational design of ***,we provide an in-depth and comprehensive discussion on the design principles and strategies for the electrodes/electrolyte/separator optimization,and analyze the advantages and disadvantages of various ***,the design principles and strategies of the newly appeared conversion-type AZIBs,such as Zn-S battery and Zn-Se battery,are also discussed and *** effect of design strategies on the electrochemical performance and the relationship between the current issues and strategies are also unveiled in ***,some research trends and perspectives are provided for designing better AZIBs.

关键词： aqueous zinc-ion batteries cathode modification design principles electrolyte regulation zinc anode optimization

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Designing a Platform to Evaluate Metal Oxide Varistors for DC Circuit Breaker Applications

Designing a Platform to Evaluate Metal Oxide Varistors for D...

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electrical Insulation Conference and electrical Manufacturing & Coil Winding Conference

作者： Yang Liu Zhi Jin Zhang Kayla Chuong Zhiyang Jin Lauren Garten Lukas Graber Schoole of Electrical and Computer Engineering Georgia Institute of Technology Atlanta U.S. School of Material Science and Engineering Georgia Institute of Technology Atlanta U.S.

ISBN: (数字)9798350360431

ISBN: (纸本)9798350360448

Design of a metal oxide varistor (MOV) evaluation platform was introduced and implemented in this work. The key challenges included mimicking critical features of dc power grid, aging the MOV samples at a desired speed under desired conditions, and keeping the platform much more robust than the samples. Also, necessary protection is considered for unpredictable faults in the test system for both software and hardware failures. The goal of building this platform is to understand aging and degradation of MOVs under dc circuit breaker application. The uniqueness of dc circuit breaker MOV waveform and duality between multi-MOV dc circuit breaker and the single MOV evaluation platform is introduced.

关键词： Degradation Varistors Insulation Circuit breakers Metals Aging Software

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Improving the Microstructure of ZnO-Based Metal Oxide Varistors Using Cold Sintering

Improving the Microstructure of ZnO-Based Metal Oxide Varist...

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electrical Insulation Conference and electrical Manufacturing & Coil Winding Conference

作者： Kayla Chuong Yang Liu Lukas Graber Lauren M. Garten School of Material Science and Engineering Georgia Institute of Technology Atlanta U.S Schoole of Electrical and Computer Engineering Georgia Institute of Technology Atlanta U.S

ISBN: (数字)9798350360431

ISBN: (纸本)9798350360448

Metal oxide varistors (MOVs) are well established as surge arrestors to protect AC power transmission and distribution apparatus. Unlike the rare lightning-induced surges in AC application, MOVs are required to absorb energy repeatedly and frequently in DC circuit breakers (DCCBs). Therefore, further advances in lifetime and reliability are needed to develop MOVs for high-efficiency DCCBs. Microstructure in MOVs has been found to dictate device nonlinearity, voltage breakdown, and lifetime. In ZnO-based MOVs, smaller grains and increased grain homogeneity has been shown to extend the lifetime of MOVs, but the ability to control grain growth has previously been limited by the high temperatures needed to densify ZnO. Here, cold sintering is proposed as a route to minimize grain growth during the sintering process of ZnO-based MOVs. In cold sintering, increased pressure and liquid phase transport promote densification at lower temperatures. The microstructure of cold sintered ZnO MOVs processed with varied pressure and liquid phase compositions are compared to high temperature sintered samples to assess the potential for microstructure control. Density, the critical metric for fully sintered MOVs, was measured using a gas pycnometer, the microstructure was assessed using scanning electron microscopy (SEM), while impedance analysis was done to observe the electrical response. Sintering at 1100 °C for two hours resulted in grain sizes averaging 4.1 μm, but cold sintering at 400 MPa at 150 °C for 30 min reduced grain growth, resulting in grain sizes of 0.2-0.3 μm. Cold sintering was shown to produce homogenous microstructures with improved electrical properties while reducing energy consumption due to sintering at lower temperatures and times.

关键词： Grain size Temperature measurement Varistors Liquids II-VI semiconductor materials Sintering Zinc oxide

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For sky-facing passive radiative cooling, are wavelength-selective emitters the best choice?

arXiv

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arXiv 2024年

作者： Jin, Yeonghoon Kats, Mikhail Department of Electrical and Computer Engineering University of Wisconsin-Madison MadisonWI United States Department of Material Science and Engineering University of Wisconsin-Madison MadisonWI United States

For passive cooling via thermal radiation toward the sky, it is known that an ideal selective emitter (SE) with high emissivity only in the 8–13 µm atmospheric transparency window can reach a lower equilibrium temperature than an ideal broadband emitter (BE) across the mid infrared. Here, we evaluate whether this principle should guide the development of practical passive radiative cooling technologies. We model and compare the cooling performance of sky-facing SEs and BEs at various locations on Earth, accounting for the distributions of atmospheric temperature and gas composition at specific dates and times. We find that for emitter temperatures at or higher than the ambient temperature, an ideal broadband emitter always provides higher net cooling power, while for sub-ambient cooling, an ideal selective emitter is usually slightly better, but the difference in cooling power is small, at most 1-2% of the incident solar power during daytime. Our conclusion is that large-scale deployment of passive radiative cooling technologies should focus on design and manufacturing of scalable low-cost surfaces with the lowest possible solar absorption without worrying too much whether the emitter is broadband or selective. Copyright © 2024, The Authors. All rights reserved.

关键词： Atmospheric temperature

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Active Interface Characteristics of Heterogeneously Integrated GaAsSb/Si Photodiodes

arXiv

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arXiv 2024年

作者： Muduli, Manisha Xia, Yongkang Lee, Seunghyun Gajowski, Nathan Chae, Chris Rajan, Siddharth Hwang, Jinwoo Arafin, Shamsul Krishna, Sanjay Department of Electrical and Computer Engineering The Ohio State University OH43201 United States Department of Material Science and Engineering The Ohio State University OH43201 United States

There is increased interest in the heterogeneous integration of various compound semiconductors with Si for a variety of electronic and photonic applications. This paper focuses on integrating GaAsSb (with absorption in the C-band at 1550nm) with silicon to fabricate photodiodes, leveraging epitaxial layer transfer (ELT) methods. Two ELT techniques—epitaxial lift-off (ELO) and macro-transfer printing (MTP)—are compared for transferring GaAsSb films from InP substrates to Si, forming PIN diodes. Characterization through atomic force microscopy (AFM), and transmission electron microscopy (TEM) exhibits a high-quality, defect-free interface. Current-voltage (IV) measurements and capacitance-voltage (CV) analysis validate the quality and functionality of the heterostructures. Photocurrent measurements at room temperature and 200 K demonstrate the device's photo-response at 1550 nm, highlighting the presence of an active interface. Copyright © 2024, The Authors. All rights reserved.

关键词： III-V semiconductors

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Towards Efficient Automatic Oracle Synthesis and Resource Estimation Using QDK and QIR

Towards Efficient Automatic Oracle Synthesis and Resource Es...

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Quantum Computing and engineering (QCE), IEEE International Conference on

作者： I-Tung Chen Chaman Gupta Department of Electrical and Computer Engineering University of Washington Seattle WA USA Department of Material Science and Engineering University of Washington Seattle WA USA

Automatic oracle synthesis (AOS) provides a promising route to speed up the process of constructing a complex quantum oracle. Here, we expand the existing AOS in the Microsoft Quantum Development Kit (QDK) by adding new functionalities and introducing a new workflow. We also optimize the AOS process by reducing the number of T gates using measurement-based uncomputation. Furthermore, we compare the resource requirements of the oracles generated using AOS to those of the existing QDK library oracles using the Azure Quantum Resource Estimator. The results suggest that the oracles generated using AOS perform better in runtime but use more qubits compared to the corresponding QDK library oracle. With the presented workflow, one can easily implement and estimate the quantum resources required for oracles with complex arithmetic functions. Finally, we present a strategy that can further reduce the number of physical qubits needed in AOS.

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In situ construction of PtSe_(2)/Ge Schottky junction array with interface passivation for broadband infrared photodetection and imaging

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InfoMat 2024年第4期6卷 37-46页

作者： Xue Li Shuo-En Wu Di Wu Tianxiang Zhao Pei Lin Zhifeng Shi Yongtao Tian Xinjian Li Longhui Zeng Xuechao Yu School of Physics and Microelectronics Key Laboratory of Material Physics Ministry of EducationZhengzhou UniversityZhengzhouHenanthe People's Republic of China Department of Electrical and Computer Engineering University of CaliforniaLa JollaCaliforniaUSA National Research Center for Optical Sensors/Communications Integrated Networks School of Electronic Science and EngineeringSoutheast UniversityNanjingJiangsuthe People's Republic of China Key Laboratory of Multifunctional Nanomaterials and Smart Systems Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhouJiangsuthe People's Republic of China

Infrared(IR)detection is vital for various military and civilian *** research has highlighted the potential of two-dimensional(2D)topological semimetals in IR detection due to their distinctive advantages,including van der Waals(vdW)stacking,gapless electronic structure,and Van Hove singularities in the electronic density of ***,challenges such as large-scale patterning,poor photoresponsivity,and high dark current of photodetectors based on 2D topological semimetals significantly impede their wider applications in low-energy photon ***,we demonstrate the in situ fabrication of PtSe_(2)/Ge Schottky junction by directly depositing 2D PtSe_(2) films with a vertical layer structure on a Ge substrate with an ultrathin AlOx *** to high quality junction,the photodetector features a broadband response of up to 4.6μm,along with a high specific detectivity of�1012 Jones,and operates with remarkable stability in ambient conditions as ***,the highly integrated device arrays based on PtSe_(2)/AlOx/Ge Schottky junction showcases excellent Mid-IR(MIR)imaging capability at room *** findings highlight the promising prospects of 2D topological semimetals for uncooled IR photodetection and imaging applications.

关键词： broadband photodetection imaging platinum diselenide Schottky junction van der Waals integration

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Periodic domain inversion in single crystal barium titanate-on-insulator thin film

arXiv

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arXiv 2024年

作者： Aashna, Pragati Lin, Hong-Lin Cao, Yu Yin, Yuhui Gao, Yuan Mohanraj, Sakthi Sanjeev Zhu, Di Danner, Aaron Department of Electrical and Computer Engineering National University of Singapore 117583 Singapore Department of Material Science and Engineering National University of Singapore 119077 Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research 138634 Singapore

We report experimentally achieving first-ever electric field periodic poling of single crystal barium titanate (BTO, or BaTiO3) thin film on insulator. Owing to the outstanding optical nonlinearities of BTO, this result is a key step towards achieving quasi-phase-matching in BTO. We first grow the BTO thin film on a dysprosium scandate substrate using pulsed laser deposition with a thin layer of strontium ruthenate later serving as the bottom electrode for poling. We present characterization of the BTO thin film using x-ray diffraction and piezo-response force microscopy to clearly demonstrate single crystal, single domain growth of the film which enables the desired periodic poling. To investigate the poling quality, we apply both non-destructive piezo force response microscopy and destructive etching-assisted scanning electron microscopy and we show that high quality, uniform and intransient poling with 50 % duty cycle and periods ranging from 2 μm to 10 μm is achieved. The successful realization of periodic poling in BTO thin film unlocks the potential for highly efficient nonlinear processes under quasi-phase-matching that seemed far-fetched with prior polycrystalline BTO thin films which predominantly relied on efficiency-limited random or non-phase matching conditions and is a key step towards integration of BTO photonic devices. Copyright © 2024, The Authors. All rights reserved.

关键词： Thin films

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Multiscale Modelling of Curved Pixel Arrays

Multiscale Modelling of Curved Pixel Arrays

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International Conference on Numerical Simulation of Optoelectronic Devices, (NUSOD)

作者： Enrico Bellotti John Glennon Mike Zhu Alex Kyrtsos Andreu Glasmann Electrical and Computer Engineering Department Boston University Boston MA USA Division of Material Science and Engineering Boston University Boston MA USA

Large format infrared (IR) detector arrays that provide high image resolution over a wide field of view (WFOV), are of critical importance for both defense and civilian applications, for example surveillance, astronomy, and remote sensing. Reduction of pixel pitch has been aggressively pursued to increase the array format, and the pixel dimension is approaching a size comparable to the wavelength. While significant progress has been made to increase the resolution of IR focal plane arrays (FPA), a considerable effort is still required to design the optics needed to implement the camera. For applications where a WFOV is needed, the camera optics has to be designed to mitigate the optical aberrations that degrade illumination and resolution uniformity across the FPA. This is currently achieved by employing many optical elements to flatten the Petzval field curvature to match the footprint of the planar image sensor. As a result of the complex optics needed to achieve field flattening, and at the same time to minimize other aberrations, the size, weight, and cost of the entire camera increases considerably.

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