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Dramatic reduction in dark current ofβ-Ga_(2)O_(3) ultraviolet photodectors viaβ-(Al_(0.25)Ga_(0.75))_(2)O_(3) surface passivation

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Chinese Physics B 2023年第1期32卷 415-420页

作者：岳建英季学强李山岐晓辉李培刚吴真平唐为华 Laboratory of Optoelectronics Materials and Devices School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China College of Electronic and Optical Engineering&College of Microelectronics National and Local Joint Engineering Laboratory for RF Integration and Micro-Packaging TechnologiesNanjing University of Posts and TelecommunicationsNanjing 210046China

Solar-blind ultraviolet photodetectors with metal-semiconductor-metal structure were fabricated based onβ-(Al_(0.25)Ga_(0.75))_(2)O_(3)/β-Ga_(2)O_(3) film grown by metal-organic chemical vapor *** was known that various surface states increase dark current and a large number of defects can hinder the transport of carriers,resulting in low switching ratio and low responsivity of the *** this work,β-(Al_(0.25)Ga_(0.75))_(2)O_(3) films are used as surface passivation *** to its wide band gap,we obtain excellent light transmission and high lattice matching withβ-Ga_(2)O_(3).We explore the change and mechanism of the detection performance of theβ-Ga_(2)O_(3) detector afterβ-(Al_(0.25)Ga_(0.75))_(2)O_(3) surface *** is found that under the illumination with 254 nm light at bias 5 V,theβ-(Al_(0.25)Ga_(0.75))_(2)O_(3)/β-Ga_(2)O_(3)photodetectors show dark current of just 18 pA and high current on/off ratio of 2.16×10^(5).The dark current is sharply reduced about 50 times after passivation of theβ-Ga_(2)O_(3) surface,and current on/off ratio increases by approximately 2 *** is obvious thatβ-Ga_(2)O_(3) detectors withβ-(Al_(0.25)Ga_(0.75))_(2)O_(3) surface passivation can offer superior detector performance.

关键词： β-(Al_(0.25)Ga_(0.75))_(2)O_(3)/β-Ga_(2)O_(3) MOCVD photodetectors defect passivation

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Circularly Polarized Leaky-wave Antenna Based on SubstrateIntegrated Waveguide Space Harmonic

Circularly Polarized Leaky-wave Antenna Based on SubstrateIn...

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International Symposium on Antennas and Propagation (ISAP)

作者： Yangjun Hu Leilei Liu Yangbing Jiang Dingwei Jiang Minghong Chen National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology Nanjing University of Posts and Telecommunications Nanjing China

A circularly polarized leaky-wave antenna (LWA) is implemented on the substrate integrated waveguide (SIW) based on space harmonic radiation. The LWA cuts the current in two different directions by opening a cross-shaped slot on the substrate integrated waveguide. It realizes circular polarization and frequency sweeping characteristics by adjusting parameters of the slot. The antenna achieves a sweep range of 36°~13° in the θ direction backward radiation by -1 space harmonic from 15GHz to 17GHz. The gain is basically above 13.5dB. Parameters of the cross-shaped slot on the antenna performance are studied. The antenna is fabricated and the measurement results are agree well with the simulation ones.

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Security Analysis of Blockchain Smart Contract: Taking Reentrancy Vulnerability as an Example 7th

Security Analysis of Blockchain Smart Contract: Taking Reent...

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7th International Conference on Artificial Intelligence and Security, ICAIS 2021

作者： Ji, Mingtao Liang, GuangJun Li, Meng Zhang, Haoyan He, Jiacheng Department of Computer Information and Cyberspace Security Jiangsu Police Institute Nanjing China National and Local Joint Engineering Laboratory of Radio Frequency Integration and Micro Assembly Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9783030786205

As the blockchain enters the 2.0 era, the smart contract which is based on the blockchain platform has gradually entered people’s field of vision. By its transparency, non-tampering, independence from third-party arbitration, and trustlessness, it is widely applied in equity crowdfunding, games, insurance, particularly the Internet of Things. However, the attack on the TheDAO smart contract alert public awareness of the security of a smart contract. The essence of the smart contract is an electronic contract written in code. Due to reasons like lacking standard libraries for its programming language, several loopholes will inevitably appear in the code. Once they are found by attackers, the interests of the main body using smart contracts will be damaged. There are many types of vulnerabilities in smart contracts, such as reentrancy, short address attacks, and timestamp dependence. This article mainly focuses on re-entry vulnerabilities as the research object and analyzes the principle of re-entry vulnerabilities. Featuring immutable after being chained, the smart contract must be checked before it is chained to make up for the vulnerability. This paper provides a detection method based on symbolic execution to detect reentrancy vulnerabilities. We hope to strengthen people’s security awareness of smart contracts and boost the research of smart contracts in terms of security by our study of the smart contract reentrancy vulnerability in this article. Promote the research and development of smart contracts. © 2021, Springer Nature Switzerland AG.

关键词： Smart contract

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A Survey of Chips Security technology Based on Scan Chain

A Survey of Chips Security Technology Based on Scan Chain

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2023 International Symposium of Electronics Design Automation, ISEDA 2023

作者： Zou, Jing Cai, Zhikuang Xu, Xun Yang, Hang Guo, Yufeng National and Local Jiont Engineering Coll. of Intgd. Circuit Secience and Engineering Nanjing University of Posts and Telecommunications Laboratory of RF Intergration and Micro-Assembly Technology Nanjing China

ISBN: (纸本)9798350304510

Scan chain insertion is a widely used technique in design for testability (DFT), which brings high fault coverage, good controllability and observability to chip testing. But for the encryption chip, the attacker can use the scan chain to carry out side channel attack on the chip, and leak the encrypted data in the chip. In order to ensure the security of the chip, scholars in this field have done a lot of research. They exposed the attackers against the AES hardware encryption algorithm attack methods, and put forward a series of corresponding security countermeasures, such as complex DFT structure, modify scan chain structure, scan I/O restriction and so on. In this paper, we deeply analyze and summarize the attack methods and security countermeasures commonly used at present, compares their advantages and disadvantages and limitations, and briefly analyze the development of secure DFT technology in the future. © 2023 IEEE.

关键词： Design for testability

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Fused Confidence for Scene Text Detection via Intersection-over-Union 19

Fused Confidence for Scene Text Detection via Intersection-o...

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19th IEEE International Conference on Communication technology, ICCT 2019

作者： Zhang, Guo-Lin Ge, Li-Li Yang, Yu-Nuo Liu, Yu-Qi Sun, Ke-Xue Nanjing University of Posts and Telecommunications College of Electronic and Optical Engineering Nanjing Jiangsu210003 China Radiofrequency Integration and Micro Assembly Technology National and Local Joint Engineering Lab Nanjing Jiangsu210003 China

ISBN: (纸本)9781728105352

CNN-based scene text detection methods have achieved superior results. They are mostly implemented on the architecture of full convolution networks and non-maximum suppression (NMS) which combines two tasks of text classification and localization. However, in the NMS procedure, most filter the bounding boxes according to the classification confidence. This makes appropriately those well-located text boxes suppressed during NMS. In this paper, we propose an intersection-over-union (IOU) network to predict the IOU between the bounding box and the matched ground-truth. Then, the predicted IOU as localization confidence will be fused with the classification confidence. Furthermore, in the NMS, the classification confidence is replaced by the fused confidence as the ranking standard to preserve the accurately located text boxes. We experimented on the ICDAR2011 and ICDAR2013 datasets, the results show that the method proposed in this paper can effectively improve the accuracy of text detection. © 2019 IEEE.

关键词： Classification (of information)

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Design of a Broadband High Flatness Drive Amplifier Based on GaAs Process 8

Design of a Broadband High Flatness Drive Amplifier Based on...

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8th International Conference on Integrated Circuits and microsystems, ICICM 2023

作者： Huang, Jingjing Lin, Jie Ying, Shu Hu, Shanwen Cai, Zhikuang Guo, Yufeng Nanjing University of Posts and Telecommunications College of Integrated Circuit Science and Engineering Nanjing China Anqing Normal University School of Electronic Engineering and Intelligent Manufacturing Anqing China Nanjing University School of Electronic Science and Engineering Nanjing China National and Local Joint Engineering Laboratory of Rf Integration and Micro-Assembly Technology Nanjing China

ISBN: (纸本)9798350318517

In the rf front-end system, the drive amplifier require high flatness in the bandwidth. To adhere to the application requirements of the rf front-end circuit integration, miniaturization and high efficiency, based on the traditional theory of the drive amplifier and equalizer, this paper presents a design method to match the input impedance of the drive amplifier. This ensures that the matching network not only accommodates impedance matching but also enhances in-band flatness. To verify the reliability of this method, we developed a compact, high flatness drive amplifier utilizing the GaAs pHEMT process. The device operates in a frequency range of 2-6 GHz and covers WiFi, satellite and radio positioning. The small-signal gain is 23.5± 0.1dB, and both the input and output return loss are less than -12dB. Large-signal test reveal that the saturated output power of the whole broadband is greater than 22.5 dBm, and the corresponding power-added efficiency is greater than 34%. The test results demonstrate enhanced flatness compared to the traditional drive amplifiers. © 2023 IEEE.

关键词： Equalizers

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Design of a Broadband Miniaturized Filter Power Amplifiers 8

Design of a Broadband Miniaturized Filter Power Amplifiers

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8th International Conference on Integrated Circuits and microsystems, ICICM 2023

作者： Liao, Xiang Huang, Jingjing Ying, Shu Hu, Shanwen Wang, Zixuan Guo, Yufeng Nanjing University of Posts and Telecommunications College of Integrated Circuit Science and Engineering Nanjing China Anqing Normal University School of Electronic Engineering and Intelligent Manufacturing Anqing China Nanjing University School of Electronic Science and Engineering Nanjing China National and Local Joint Engineering Laboratory of Rf Integration and Micro-Assembly Technology Nanjing China

ISBN: (纸本)9798350318517

In order to meet the application requirements of rf front-end circuit integration, miniaturization and high efficiency, compared with the traditional concept of direct cascading of power amplifier and filter, this paper proposes a design method of co-designing high out-of-band rejection filter and power amplifier matching network, which matches the input impedance of the filter directly to the optimal output impedance of the drain of the output stage of the power amplifier, so that the filter network has both filtering and impedance transformation functions. By matching the input impedance of the filter directly to the optimal output impedance of the drain of the power amplifier output stage, the filter network here not only has the function of filtering but also has the function of impedance transformation. In order to verify the effectiveness and practicality of the method, a broadband miniaturized filtered power amplifier with integrated filtering characteristics is designed to operate in the 14-18 GHz satellite communication band by taking advantage of the high output power of GaAs pHEMT devices. Simulation results show that, under the premise of maximizing the output power and efficiency of the power amplifier, the gain is up to 23 dB, the input and output returns are below -15 dB, the minimum power added efficiency is 46%, the suppression of out-of-band signals reaches -30 dB, and the power suppression of the high harmonics reaches -50 dBc, which is a great improvement compared with the out-of-band suppression of conventional power amplifiers. © 2023 IEEE.

关键词： Efficiency

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A Compact Low-Loss Bi-directional Amplifier for Ku-band 8

A Compact Low-Loss Bi-directional Amplifier for Ku-band

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8th International Conference on Integrated Circuits and microsystems, ICICM 2023

作者： Lin, Jie Liao, Xiang Ying, Shu Hu, Shanwen Cai, Zhikuang Guo, Yufeng Nanjing University of Posts and Telecommunications College of Integrated Circuit Science and Engineering Nanjing China Anqing Normal University School of Electronic Engineering and Intelligent Manufacturing Anqing China Nanjing University School of Electronic Science and Engineering Nanjing China National and Local Joint Engineering Laboratory of Rf Integration and Micro-Assembly Technology Nanjing China

ISBN: (纸本)9798350318517

Conventional bi-directional amplifiers connect transceiver circuits through two T/R switches that are large in area and introduce some loss at high frequencies. In this paper, a compact low-loss bi-directional amplifier for Ku-band (receive: 12-13 GHz, transmit: 15.5-16.5 GHz) has been designed on a TSMC 65 nm 1P9M CMOS process and employs two triple-coil-coupled transceive matching network multiplexing transformers to connect transceiver circuits. When the circuit is in the transmitting state, the power amplifier achieves a 1 dB compression point of 6.321 dBm and the peak PAE is close 30%. When the circuit is in the receiving state, the low-noise amplifier boasts a remarkable in-band gain exceeding 25.7 dB, accompanied by a NF of less than 3.5 dB. The area of the triple-coil coupling transformer is approximately 200∗200 μ m2, which reducing the overall area of the bi-directional amplifier. The high-frequency insertion loss of the structure is about 1 dB, which is less than the 2 dB insertion loss of conventional switches at high frequencies. This design can be widely used in Ku-band phased array radars. © 2023 IEEE.

关键词： Insertion losses

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A New Domain Decomposition Scheme for Electromagnetic Wave Scattering from Penetrable Targets 5

A New Domain Decomposition Scheme for Electromagnetic Wave S...

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5th IEEE International Conference on Computational Electromagnetics, ICCEM 2019

作者： Zheng, Kai-Lai Chu, Peng Kong, Wei-Bin Xu, Feng College of Electronic and Optical Engineer Nanjing University of Posts and Telecommunications Nanjing210023 China National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology China State Key Lab. of Millimeter Waves Southeast University Nanjing210096 China College of Information Engineering Yancheng Insitute of Technology Yancheng China

ISBN: (纸本)9781538671115

In this paper, a new nonoverlapping domain decomposition (DD) scheme is built for solving EM scattering from penetrable targets. The Rao-Wilton-Glisson(RWG) basis functions are used to expand the equivalent surface electric/magnetic current on the entire surface. Each full RWG basis function across some boundary curve is split into two half-RWG basis functions. The global MoM matrix equation is then combined with the sparse matrix equation determined by the boundary electric/magnetic current continuity to form the complete model equation. In this DD scheme, when solving each subdomain, only part of the matrix needs to be stored into memory, and then the memory requirement is significantly reduced. Numerical examples are provided to demonstrate the validity of the proposed method. © 2019 IEEE.

关键词： Electromagnetic wave scattering

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Double Dielectrics Enhancement on the Ldmos Using High-K Field Dielectric and Low-K Buried Dielectric

SSRN

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SSRN 2022年

作者： Yao, Jiafei Liu, Xin Sun, Mingshun Xu, Tianci Li, Man Chen, Jing Zhang, Maolin Zhang, Jun Guo, Yufeng Nanjing University of Posts and Telecommunications Nanjing China National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology Nanjing China

This paper investigates the double dielectrics enhancement LDMOS (DDE LDMOS) with high-k field dielectric and low-k buried dielectric. The analytical models of the potential and electric field, optimal breakdown voltage and drift doping concentration are established for this novel LDMOS. The validity of the analytical models is confirmed by the simulation results. Based on the analytical and simulate results, the modulation mechanism of the high-k field dielectric and low-k buried dielectric on the electric field and breakdown characteristics of DDE LDMOS are analyzed and compared. Compared to the conventional LDMOS, the specific on-resistance of DDE LDMOS is reduced by 19%, the breakdown voltage and figure of merit ( FOM ) of the DDE LDMOS can be improved by 62% and 222.4% when the permittivity of high-k field dielectric and low-k buried dielectric are 100 and 2. Meanwhile, the transfer characteristic, output characteristic, frequency characteristic and switching characteristic of the DDE LDMOS are also discussed. © 2022, The Authors. All rights reserved.

关键词： MOS devices

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