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Emergence of photoluminescence on bulk MoS2 by laser thinning and gold particle decoration

Nano Research 2018年第9期11卷 4574-4586页

作者： Lili Gong Qi Zhang Liangjun Wang Jianfeng Wu Cheng Han Bo Lei Wei Chen Goki Eda Kuan Eng Johnson Goh Chorng Haur Sow Department of Physics National University of Singapore Singapore 117542 Singapore Department of Chemistry National University of Singapore Singapore 117542 Singapore Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research (A＊STAR) 2 Fusionopolis Way Innovis #08-03 Singapore 138634 Singapore

We demonstrate a facile and effective approach to significantly improve the photoluminescence of bulk MoS2 via laser thinning followed by gold particle decoration. Upon laser thinning of exfoliated bulk MoSz photoluminescence emerges from the laser-thinned region. After further treatment with an AuCl3 solution, gold particles self-assemble on the laser-thinned region and thick edges, further increasing the fluorescence of bulk MoS2 28 times and the Raman response 3 times. Such fluorescence enhancement can be attributed to both surface plasmon resonance and p-type doping induced by gold particles. The combination of laser thinning and AuCl3 treatment enables the functionalization of bulk MoS2 for optoelectronic applications. It can also provide a viable strategy for mask-free and area-selective p-type doping on single MoS2 flakes.

关键词： bulk MoS photoluminescence laser thinning gold particle plasmonic effect doping

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Microstructure induced galvanic corrosion evolution of SAC305 solder alloys in simulated marine atmosphere

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Journal of materials science & Technology 2020年第16期47卷 40-53页

作者： Mingna Wang Chuang Qiao Xiaolin Jiang Long Hao Xiahe Liu Department of Physics Hebei Normal University of Science&TechnologyQinhuangdao 066004China School of Metallurgy Northeastern UniversityShenyang 110819China Environmental Corrosion Centre of Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Material Science and Engineering University of Science and Technology of ChinaHefei 230026China

Motivated by the increasing use of Sn-3.0 Ag-0.5 Cu(SAC305)solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds(IMCs)inβ-Sn matrix,comb-like electrodes have been designed for in-situ EIS measurements to study the microstructure induced galvanic corrosion evolution of SAC305 solder in simulated marine atmosphere with high-temperature and *** indicate that in-situ EIS measurement by comb-like electrodes is an effective method for corrosion evolution behavior study of SAC305 ***,the galvanic effect between Ag3Sn IMCs andβ-Sn matrix can aggravate the corrosion of both as-received and furnace-cooled SAC305 solder as the exposure time proceeds in spite of the presence of corrosion product *** corrosion can be preferentially found on furnace-cooled SAC305 with larger Ag3Sn grain ***,the generated inner stress during phases transformation process with Sn3O(OH)2Cl2 as an intermediate and the possible hydrogen evolution at local acidified sites are supposed to be responsible for the loose,porous,cracked,and non-adherent corrosion product *** findings clearly demonstrate the corrosion acceleration behavior and mechanism of SAC305 solder,and provide potential guidelines on maintenance of microelectronic devices for safe operation and longer in-service duration.

关键词： SAC305 solder Marine atmosphere Galvanic corrosion In-situ EIS Comb-like electrode

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Structural,Wettability and Optical Investigation of Titanium Oxynitride Coatings:Effect of Various Sputtering Parameters

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Journal of materials science & Technology 2012年第6期28卷 512-523页

作者： Sushant K Rawal Amit Kumar Chawla R.Jayaganthan Ramesh Chandra Centre of Nanotechnology Indian Institute of Technology RoorkeeRoorkee-247667India Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology RoorkeeRoorkee-247667India Department of Mechanical Engineering Charotar University of Science and TechnologyChanga 388421India Department of Physics University of Petroleum and Energy StudiesDehradun-48007India Department of Metallurgical and Materials Engineering Indian Institute of Technology RoorkeeRoorkee-247667India

The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiO=N and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiO=Ny and TiN phases. The stress and strain calculated by sin2~ method are compressive, which decrease with increasing nitrogen flow rate from 55 to I00 sccm （standard cubic centimeter per minute） and increase with increasing deposition time from 80 to I40 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of I09.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.

关键词： Titanium oxynitride Sputtering parameters Contact angle Optical properties

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Urinalysis with molecularly imprinted poly(ethylene-co-vinyl alcohol) potentiostat sensors

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Biosensors and Bioelectronics 2009年第8期24卷 2611-2617页

作者： Huang, Chun-Yueh Tsai, Tain-Chin Thomas, James L. Lee, Mei-Hwa Liu, Bin-Da Lin, Hung-Yin Department of Electrical Engineering National University of Tainan Tainan 700 Taiwan Institute of Biotechnology National University of Kaohsiung Kaohsiung 811 Taiwan Department of Physics and Astronomy University of New Mexico Albuquerque NM 87131 United States Department of Materials Science and Engineering I-Shou University Kaohsiung 840 Taiwan Department of Electrical Engineering National Cheng Kung University Tainan 701 Taiwan Department of Chemical and Materials Engineering National University of Kaohsiung Kaohsiung 811 Taiwan

Among many important biomarkers excreted in urine are albumin, uric acid, glucose, urea, creatine and creatinine. In the growing elderly population, these biomarkers may be useful correlates with kidney dysfunction, infection and related problems such as glomerular, proximal, and distal convoluted tubule functions, diabetes, hypertension and proteinuria. This study employed solvent evaporation processing of poly(ethylene-co-vinyl alcohol), (EVAL) to form molecularly imprinted polymers (MIPs) that recognize creatinine, urea, and lysozyme. The mole ratio of ethylene to vinyl alcohol affected the performance: 27 mol% ethylene gave the highest imprinting effectiveness for creatinine and urea, while 44 mol% gave the highest effectiveness for lysozyme. Electrochemical examination using a home made potentiostat and imprinted polymer electrode showed electrical signals responsive to the target molecules. Finally, an actual urine sample was tested using the electrode. The test results were compared with those of the commercial instrument ARCHITECT ci 8200 system to precisely determine the accuracy of the molecularly imprinted polymer electrode for urinalysis. © 2009 Elsevier B.V. All rights reserved.

关键词： Creatinine

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Highly confined, low-loss plasmonics based on two-dimensional solid-state defect lattices

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Physical Review materials 2024年第1期8卷 L011001-L011001页

作者： Ali Ghorashi Nicholas Rivera Bowen Shi Ravishankar Sundararaman Efthimios Kaxiras John Joannopoulos Marin Soljačić Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics Harvard University Cambridge Massachusetts 02134 USA State Key Laboratory for Mesoscopic Physics and Department of Physics Peking University Beijing 100871 People's Republic of China Materials Science and Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts 02134 USA Institute for Soldier Nanotechnologies Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA

Plasmons, collective excitations of electrons in solids, are associated with strongly confined electromagnetic fields, with wavelengths far below the wavelength of photons in free space. Such strong confinement nominally holds the potential to enable optoelectronic technologies that bridge the size difference between photonic and electronic devices. However, despite decades of research in plasmonics, many applications remain limited by plasmonic losses, thus motivating a search for new engineered plasmonic materials with lower losses. Among the promising candidates for low-loss plasmonic materials are solid-state lattices with flat and energetically isolated metallic bands—with commensurately small phase spaces for phonon-assisted optical losses, a major contributor to short plasmonic lifetimes. Such electronic band structures may be created by judiciously introducing an ordered lattice of defects in an insulating host material. Here, we explore this approach, presenting several low-loss, highly confined, and tunable plasmonic materials based on arrays of carbon substitutions in hexagonal boron nitride monolayers. From our first-principles calculations based on density functional theory, we find plasmonic structures with midinfrared plasmons featuring very high confinements (λvacuum/λplasmon exceeding 1400). In addition, we find that one of our materials exhibits a confinement of 700 while avoiding second-order—phonon-assisted—losses entirely (infinite quality factor at this order of perturbation theory). We provide a systematic explanation of how crystal structure, electronic bandwidth, local-field, and many-body effects inform the plasmonic dispersions and losses of these materials. The results are thus of relevance to low-loss plasmon engineering in other flat band systems.

关键词： Doping effects Flat bands Magnetism Phonons Photonics Plasma oscillations Plasmonics Plasmons

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Magneto-Transport and Shubnikov–de Haas Oscillations in the Type-Ⅱ Weyl Semimetal Candidate NbIrTe4 Flake

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Chinese physics Letters 2019年第7期36卷 72-76页

作者： Xiang-Wei Huang Xiao-Xiong Liu Peng Yu Pei-Ling Li Jian Cui Jian Yi Jian-Bo Deng Jie Fan Zhong-Qing Ji Fan-Ming Qu Xiu-Nian Jing Chang-Li Yang Li Lu Zheng Liu Guang-Tong Liu Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 Department of Physics Lanzhou University Lanzhou 730000 Centre for Programmable Materials School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore University of Chinese Academy of Sciences Beijing 100049 5Ningbo Institute of Industrial Technology Chinese Academy of Sciences Ningbo 315201 Songshan Lake Materials Laboratory Dongguan 523808 Collaborative Innovation Center of Quantum Matter Beijing 100871

We report on magnetoresistance, Hall effect, and quantum Shubnikov–de Haas oscillation(SdH) experiments in NbIrTe4 single crystals, which was recently predicted to be a type-II Weyl semimetal. NbIrTe4 manifests a non-saturating and parabolic magnetoresistance at low temperatures. The magneto-transport measurements show that NbIrTe4 is a multiband system. The analysis of the SdH oscillations reveals four distinct oscillation frequencies. Combined with the density-functional theory calculations, we show that they come from two types of Fermi surfaces: electron pocket E1 and hole pocket H2.

关键词： Haas was SdH be

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Excellent photocatalytic performance under visible-light irradiation of ZnS/rGO nanocomposites synthesized by a green method

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Frontiers of materials science 2016年第4期10卷 385-393页

作者： Hassan Rayat AZIMI Mahmood GHORANNEVISS Seyed Mohammad ELAHI Mohammad Reza MAHMOUDIAN Farid JAMALI-SHEINI Ramin YOUSEFI Plasma Physics Research Center Science and Research Branch Islamic Azad University Tehran Iran Department of Chemistry Shahid Sherafat University of Farhangian 15916 Tehran Iran Advanced Surface Engineering and Nano Materials Research Center Department of Physics Ahvaz Branch Islamic Azad University Ahvaz Iran Department of Physics Masjed-Soleiman Branch isiamic Azad University Masjed-Soleiman Iran

ZnS/graphene nanocomposites with different graphene concentrations （5, 10 and 15 wt.%） were synthesized using L-cysteine as surfactant and graphene oxide （GO） powders as graphene source. Excellent performance for nanocomposites to remove methylene blue （MB） dye and hexavalent chromium （Cr（VI）） under visible-light illumina- tion was revealed. TEM images showed that ZnS NPs were decorated on GO sheets and the GO caused a significant decrease in the ZnS diameter size. XRD patterns, XPS and FTIR spectroscopy results indicated that GO sheets changed into reduced graphene oxide （rGO） during the synthesis process. Photocurrent measurements under a visible- light source indicated a good chemical reaction between ZnS NPs and rGO sheets.

关键词： ZnS/rGO nanocomposites graphene photocatalytic performance watertreatment green nanotechnology

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Macroscopic Discolorization in Quantum Dot Color Converters for Microdisplay Applications

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ACS Applied Nano materials 2024年第7期7卷 8258-8268页

作者： Lin, Chen-Te Chen, Hsueh-Shih Ph.D. Program in Prospective Functional Materials Industry College of Engineering National Tsing Hua University Hsinchu30013 Taiwan Department of Materials Science and Engineering National Tsing Hua University Hsinchu30013 Taiwan College of Semiconductor Research National Tsing Hua University Hsinchu30013 Taiwan

Quantum dot color converters (QDCCs) currently have the unsolved problems of photostability and discolorization in appearance after long-term operation in microdisplays. Instead of polymer-to-carbon conversion and/or impurity precipitation, the macroscopic bright-yellow-to-dark-brown discolorization is determined by microscopic interfacial chemical reactions of the QD-ligand-polymer system. The phenomenon has been confirmed to be related to multiple factors, including chemical transformation of the QD shell and partial degradation of the polymer, resulting in increased optical reflectance and reduced photoluminescence (PL) intensity in QDCCs. Our finding suggests that the photoexcitation of QDs in the polymer matrix should lead to detached surface ligands along with photocatalytic reactions, oxidizing the QD shell together with degrading the polymer chains. © 2024 The Authors. Published by American Chemical Society

关键词： Color

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Directional Design of materials Based on Multi-Objective Optimization:A Case Study of Two-Dimensional Thermoelectric SnSe

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Chinese physics Letters 2021年第2期38卷 84-90页

作者： Shenshen Yan Yi Wang Zhibin Gao Yang Long Jie Ren Center for Phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Department of Physics National University of SingaporeSingapore 117551Republic of Singapore Shanghai Research Institute for Intelligent Autonomous Systems Tongji UniversityShanghai 200092China

The directional design of functional materials with multi-objective constraints is a big challenge,in which performance and stability are determined by a complicated interconnection of different physical *** apply multi-objective optimization,based on the Pareto Efficiency and Particle-Swarm Optimization methods,to design new functional materials *** a demonstration,we achieve the thermoelectric design of 2D SnSe materials via the above *** identify several novel metastable 2D SnSe structures with simultaneously lower free energy and better thermoelectric performance in their experimentally reported monolayer *** hope that the results of our work on the multi-objective Pareto Optimization method will represent a step forward in the integrative design of future multi-objective and multi-functional materials.

关键词： materials. methods. directional

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Microwave properties of BST and BST/BMT thin films grown on sapphire substrate by evanescent microwave probe

Microwave properties of BST and BST/BMT thin films grown on ...

引用

Seventeenth International Symposium on Integrated Ferroelectrics, ISIF-17

作者： Joseph, P.T. Chen, Yi-Chun Chu, Yin-Hao Cheng, Hsiu-Fung Tai, Nyan-Hwa Lin, I.-Nan Department of Physics Tamkang University Tamsui Taiwan Department of Physics National Cheng Kung University Tainan Taiwan Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan

Thin films of BaxSr1-xTiO3 (BST) serial materials have the advantages of adjustable tunability and are good candidates for the application in DRAM and microwave devices. However, these films usually have loss tangent higher than the order of 0.01 at microwave frequencies. To improve the crystal structures and suppress the microwave losses, an interlayer material with good microwave properties can be used. In this present work, a low loss Ba(Mg1/3Ta2/3)O3 (BMT) thin buffer layer with varying thickness and its effect on the microwave properties of Ba 0.4Sr0.6TiO3 thin films is investigated. Moreover, to overcome the spatial limit in the traditional microwave measurement, a novel technique, evanescent microwave probe (EMP) method, is used to directly probe the microwave dielectric properties of the films. This technique also provides the capability to study the dielectric mechanism in micro-scale region. Pulsed laser deposition technique was used to synthesize thin films. The films shows (111) preferably oriented growth of BST films with the introduction of BMT layer for the films grown on sapphire substrates. As the thickness of BMT increases, this behavior is more obvious. The microwave dielectric constants (Ε) and dielectric losses (tan δ) of the films grown on sapphire substrates have been measured by EMP. The dielectric constants of BST thin films decrease monotonously with the increase of BMT thickness. In contrast, the tan δ shows a discontinuity variation when the BMT buffer layer is deposited for 10-20 minutes.

关键词： Thin films

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