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576 results on '"Zeng, Qingsheng"'

58. Solid-Ionic Memory in a van der Waals Heterostructure

Author

Chen, Jieqiong, primary, Guo, Rui, additional, Wang, Xiaowei, additional, Zhu, Chao, additional, Cao, Guiming, additional, You, Lu, additional, Duan, Ruihuan, additional, Hadke, Shreyash Sudhakar, additional, Cao, Xun, additional, Salim, Teddy, additional, Buenconsejo, Pio John S., additional, Xu, Manzhang, additional, Zhao, Xiaoxu, additional, Zhou, Jiadong, additional, Deng, Ya, additional, Zeng, Qingsheng, additional, Wong, Lydia H., additional, Chen, Jingsheng, additional, Liu, Fucai, additional, and Liu, Zheng, additional

Published
2022
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62. Transient Modeling of Ultra Wideband Pulse Propagation

Author

Zeng, Qingsheng and Chubukjian, Arto

Abstract

Numerical inversion of Laplace transform and Prony’s method are discussed. The conditions under which numerical inversion of Laplace transform can be applied in practice are clarified. The approach combining numerical inversion of Laplace transform with Prony’s method is applied to the analysis of transient reflection of UWB pulses from a conductive interface. Numerical results are illustrated and compared with those published in the literature. A good agreement between them validates the correctness and effectiveness of this approach. With the evaluation of transient direct and reflected waves, the impacts of multipath components on pulse distortion and UWB system performance in a hallway environment are discussed. The significance of this work is twofold: First, the methodology combines the time domain electromagnetics and the UWB system theory, and lends us the powerful methods and rich solutions already available to gain insight into UWB problems. Second, the efficiency of the methodology is improved, leading to simple implementation, low computation cost, easy estimation and control of errors. Based on the studies of pulses reflected from a conducting interface, characterization of pulses propagating through a lossy dielectric slab is pursued. Our results are shown to be comparable to the previously published results and agree well with those obtained using the FDTD technique. Furthermore, the corresponding results for an incident angle close to 900 can be provided with this technique, which can not be generated with the previous approaches. This efficient time domain technique can be extended in a straightforward manner to the transient analysis of multiple reflections and transmissions in lossy media, and thus provide a powerful tool for electromagnetic analysis and design.

Published
2021

63. A Novel Dual-Band Waveguide Filter With Multiple Transmission Zeros Based on TE 102 - and TE 103 -Modes.

Author

Wu, Yong and Zeng, Qingsheng

Abstract

In this letter, the authors propose a novel dual-band waveguide filter with multiple transmission zeros (TZs) based on multi-coupled resonators in the rectangular waveguide using TE102- and TE103-modes. The dual-band of the filter is implemented by five oversized resonant cavities working in TE102- and TE103-modes with the central frequencies of the pass-bands close to 30.1 and 38.2 GHz, respectively. This rectangular waveguide filter consists of five resonators, each of which is connected to the source port through the narrow wall of the WR-28 rectangular waveguide, generating multiple TZs in the frequency range 26–40 GHz. To verify the performance of this novel filter, a prototype of it is fabricated and measured, achieving a good agreement between the simulated and measured results. [ABSTRACT FROM AUTHOR]

Published
2022
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66. Controlled Synthesis of MoxW1–xTe2 Atomic Layers with Emergent Quantum States

Author

Deng, Ya, primary, Li, Peiling, additional, Zhu, Chao, additional, Zhou, Jiadong, additional, Wang, Xiaowei, additional, Cui, Jian, additional, Yang, Xue, additional, Tao, Li, additional, Zeng, Qingsheng, additional, Duan, Ruihuan, additional, Fu, Qundong, additional, Xu, Jianbin, additional, Qu, Fanming, additional, Yang, Changli, additional, Jing, Xiunian, additional, Lu, Li, additional, Liu, Guangtong, additional, and Liu, Zheng, additional

Published
2021
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68. Chemical Vapor Deposition of Superconducting FeTe1–xSex Nanosheets

Author

Hu, Dianyi, primary, Ye, Chen, additional, Wang, Xiaowei, additional, Zhao, Xiaoxu, additional, Kang, Lixing, additional, Liu, Jiawei, additional, Duan, Ruihuan, additional, Cao, Xun, additional, He, Yanchao, additional, Hu, Junxiong, additional, Li, Shengyao, additional, Zeng, Qingsheng, additional, Deng, Ya, additional, Yin, Peng-Fei, additional, Ariando, Ariando, additional, Huang, Yizhong, additional, Zhang, Hua, additional, Wang, Xiao Renshaw, additional, and Liu, Zheng, additional

Published
2021
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70. MoO₃-MoS₂ vertical heterostructures synthesized via one-step CVD process for optoelectronics

Author

Guo, Yuxi, Kang, Lixing, Song, Pin, Zeng, Qingsheng, Tang, Bijun, Yang, Jiefu, Wu, Yao, Tian, Dan, Xu, Manzhang, Zhao, Wu, Qi, Xiaofei, Zhang, Zhiyong, Liu, Zheng, and School of Materials Science and Engineering

Subjects
Chemical Vapor Deposition, Materials [Engineering], 2D Materials
Abstract

The 2D transitional metal oxides/transition-metal dichalcogenides vertical heterostructures of MoO3–MoS2 are successfully synthesized on SiO2/Si substrates via one-step chemical vapor deposition process. The vertical MoO3–MoS2 heterostructures exhibit the average size of ∼20 µm and the thickness down to ∼10 nm. Moreover, the phototransistor device based on MoO3–MoS2 heterostructures presents responsivity of 5.41 × 103 A W−1, detectivity of 0.89 × 1010 Jones and external quantum efficiency of 1263.4%, respectively, under a 532 nm wavelength light. This study affords a new path to simplify process of fabricating MoO3–MoS2 vertical heterostructures for electronic and optoelectronic applications. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) National Research Foundation (NRF) This work was supported by the National Research Foundation–Competitive Research Program of Singapore NRF-CRP21-2018-0007 and CRP22- 2019-0060, MOE Tier 2 MOE2017-T2-2-136, Tier 3 MOE2018-T3-1-002, and A∗ Star QTE programme. The National Natural Science Foundation of China (Grants 61974120 and 61904148), the Key Program for International Science and Technology Cooperation Project of Shaanxi Province (Grants 2018KWZ08 and 2019KW-029), the National Key Research and Development Program of China (2019YFC1520904), the Natural Science Foundation of Shaanxi Province (Grants 2017JM5135 and 2018JM6046) and the Foundation of the Education Department of Shaanxi Province (Grans 18JK0772 and 18JK0780), the Key Research and Development Program of Shaanxi Province (2018GY-025).

Published
2021

71. Chemical Vapor Deposition of Superconducting FeTe1- xSexNanosheets

Author

Hu, Dianyi, Ye, Chen, Wang, Xiaowei, Zhao, Xiaoxu, Kang, Lixing, Liu, Jiawei, Duan, Ruihuan, Cao, Xun, He, Yanchao, Hu, Junxiong, Li, Shengyao, Zeng, Qingsheng, Deng, Ya, Yin, Peng-Fei, Ariando, Ariando, Huang, Yizhong, Zhang, Hua, Wang, Xiao Renshaw, Liu, Zheng, Hu, Dianyi, Ye, Chen, Wang, Xiaowei, Zhao, Xiaoxu, Kang, Lixing, Liu, Jiawei, Duan, Ruihuan, Cao, Xun, He, Yanchao, Hu, Junxiong, Li, Shengyao, Zeng, Qingsheng, Deng, Ya, Yin, Peng-Fei, Ariando, Ariando, Huang, Yizhong, Zhang, Hua, Wang, Xiao Renshaw, and Liu, Zheng

Abstract

FeTe1-xSex, a promising layered material used to realize Majorana zero modes, has attracted enormous attention in recent years. Pulsed laser deposition (PLD) and molecular-beam epitaxy (MBE) are the routine growth methods used to prepare FeTe1-xSex thin films. However, both methods require high-vacuum conditions and polished crystalline substrates, which hinder the exploration of the topological superconductivity and related nanodevices of this material. Here we demonstrate the growth of the ultrathin FeTe1-xSex superconductor by a facile, atmospheric pressure chemical vapor deposition (CVD) method. The composition and thickness of the two-dimensional (2D) FeTe1-xSex nanosheets are well controlled by tuning the experimental conditions. The as-prepared FeTe0.8Se0.2 nanosheet exhibits an onset superconducting transition temperature of 12.4 K, proving its high quality. Our work offers an effective strategy for preparing the ultrathin FeTe1-xSex superconductor, which could become a promising platform for further study of the unconventional superconductivity in the FeTe1-xSex system. © 2021 American Chemical Society.

Published
2021

77. Direct Laser Patterning of a 2D WSe 2 Logic Circuit

Author

Zhu, Chao, primary, Zhao, Xiaoxu, additional, Wang, Xiaowei, additional, Chen, Jieqiong, additional, Yu, Peng, additional, Liu, Song, additional, Zhou, Jiadong, additional, Fu, Qundong, additional, Zeng, Qingsheng, additional, He, Yongmin, additional, Edgar, James H., additional, Pennycook, Stephen J., additional, Liu, Fucai, additional, and Liu, Zheng, additional

Published
2021
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78. Engineering grain boundaries at the 2D limit for the hydrogen evolution reaction

Author

National Research Foundation of Korea, Ministry of Education (South Korea), Natural Science Foundation of Jiangsu Province, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, Fundación la Caixa, Engineering and Physical Sciences Research Council (UK), Office of Naval Research (US), Hong Kong University of Science and Technology, He, Yongmin, Tang, Peng-Yi, Hu, Zhili, He, Qiyuang, Zhu, Chao, Wang, Luqing, Zeng, Qingsheng, Golani, Prafful, Gao, Guanhui, Fu, Wei, Huang, Zhiqi, Gao, Caitian, Xia, Juan, Wang, Xingli, Wang, Xuewen, Ramasse, Quentin M., Zhang, Ao, An, Boxing, Zhang, Yongzhe, Martí-Sànchez, Sara, Morante, Joan Ramón, Wang, Liang, Tay, Beng Kang, Yakobson, Boris I., Trampert, Achim, Zhang, Hua, Wu, Minghong, Wang, Qi Jie, Arbiol, Jordi, Liu, Zheng, National Research Foundation of Korea, Ministry of Education (South Korea), Natural Science Foundation of Jiangsu Province, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, Fundación la Caixa, Engineering and Physical Sciences Research Council (UK), Office of Naval Research (US), Hong Kong University of Science and Technology, He, Yongmin, Tang, Peng-Yi, Hu, Zhili, He, Qiyuang, Zhu, Chao, Wang, Luqing, Zeng, Qingsheng, Golani, Prafful, Gao, Guanhui, Fu, Wei, Huang, Zhiqi, Gao, Caitian, Xia, Juan, Wang, Xingli, Wang, Xuewen, Ramasse, Quentin M., Zhang, Ao, An, Boxing, Zhang, Yongzhe, Martí-Sànchez, Sara, Morante, Joan Ramón, Wang, Liang, Tay, Beng Kang, Yakobson, Boris I., Trampert, Achim, Zhang, Hua, Wu, Minghong, Wang, Qi Jie, Arbiol, Jordi, and Liu, Zheng

Abstract

Atom-thin transition metal dichalcogenides (TMDs) have emerged as fascinating materials and key structures for electrocatalysis. So far, their edges, dopant heteroatoms and defects have been intensively explored as active sites for the hydrogen evolution reaction (HER) to split water. However, grain boundaries (GBs), a key type of defects in TMDs, have been overlooked due to their low density and large structural variations. Here, we demonstrate the synthesis of wafer-size atom-thin TMD films with an ultra-high-density of GBs, up to ~1012 cm−2. We propose a climb and drive 0D/2D interaction to explain the underlying growth mechanism. The electrocatalytic activity of the nanograin film is comprehensively examined by micro-electrochemical measurements, showing an excellent hydrogen-evolution performance (onset potential: −25 mV and Tafel slope: 54 mV dec−1), thus indicating an intrinsically high activation of the TMD GBs.

Published
2020

92. An Ultra-wideband Double-ridged Horn Antenna

Author

Xie, Wenqing, primary, Liu, Shuang, additional, Liu, Jianrui, additional, Zhang, Shuting, additional, Wang, Shuang, additional, Zhao, Lixin, additional, Hu, Nan, additional, and Zeng, Qingsheng, additional

Published
2020
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