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Nerkar SD, Ar SR, Al Mesfer MK, Ansari KB, Khan MS, Deore AB, Attarde RR. Field emission from two-dimensional (2D) CdSSe flake flowers structure grown on gold coated silicon substrate: An efficient cold cathode. Microsc Res Tech 2024. [PMID: 38856214 DOI: 10.1002/jemt.24621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/08/2024] [Accepted: 05/20/2024] [Indexed: 06/11/2024]
Abstract
Field emission finds a vital space in numerous scientific and technological applications, including high-resolution imaging at micro- and nano-scales, conducting high-energy physics experiments, molecule ionization in spectroscopy, and electronic uses. A continuous effort exists to develop new materials for enhanced field emission applications. In the present work, two-dimensional (2D) well-aligned CdSSe flake flowers (CdSSe-FFs) were successfully grown on gold-coated silicon substrate utilizing a simple and affordable chemical bath deposition approach at ambient temperature. The time-dependent growth mechanism from nanoparticles to FFs was observed at optimized parameters such as concentration of precursors, pH (~11), deposition time, and solution temperature. The crystalline nature of CdSSe-FFs is confirmed by high-resolution transmission electron microscopy (HRTEM) results, and selected area electron diffraction (SAED) observations reveal a hexagonal crystal structure. Additionally, the CdSSe-FFs thickness was confirmed by TEM analysis and found to be ~20-30 nm. The optical, photoelectric, and field emission (FE) characteristics are thoroughly explored which shows significant enhancement due to the formation of heterojunction between the gold-coated silicon substrate and CdSSe-FFs. The UV-visible absorption spectra of CdSSe-FFs show enhanced absorption at 700 nm, corresponding to the energy band gap (Eg) of 1.77 eV. The CdSSe-FFs exhibited field emission and photosensitive field emission (PSFE) characteristics. In FE study CdSSe-FFs shows an increase in current density of 387.2 μ A cm-2 in an applied field of 4.1 V m-1 which is 4.08 fold as compared to without light illumination (95.1 μ A cm-2). Furthermore, it shows excellent emission current stability at the preset value of 1.5 μA over 3 h with a deviation of the current density of less than 5% respectively. RESEARCH HIGHLIGHTS: Novel CdSSe flake flowers were grown on Au-coated Si substrate by a cost-effective chemical bath deposition route. The growth mechanism of CdSSe flake flowers is studied in detail. Field emission and Photoluminescence study of CdSSe flake flowers is characterized. CdSSe flake flowers with nanoflakes sharp edges exhibited enhanced field emission properties.
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Affiliation(s)
- Sachin D Nerkar
- Department of Applied Sciences & Humanities, SVKM's Institute of Technology, Dhule, India
| | - Shakeelur Raheman Ar
- Department of Applied Sciences & Humanities, SVKM's Institute of Technology, Dhule, India
| | - Mohammed K Al Mesfer
- Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia
| | - Khursheed B Ansari
- Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia
| | - Mohd Shariq Khan
- Department of Chemical Engineering, College of Engineering, Dhofar University, Salalah, Sultanate of Oman
| | - Amol B Deore
- Department of Applied Science and Humanities, MIT School of Computing, MIT Art, Design and Technology University, Pune, India
| | - R R Attarde
- Department of Physics, Pankaj Arts and Science College Chopda, Jalgaon, India
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Chen Y, Chen J, Li Z. Cold Cathodes with Two-Dimensional van der Waals Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2437. [PMID: 37686945 PMCID: PMC10490007 DOI: 10.3390/nano13172437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/07/2023] [Accepted: 08/14/2023] [Indexed: 09/10/2023]
Abstract
Two-dimensional van der Waals materials could be used as electron emitters alone or stacked in a heterostructure. Many significant phenomena of two-dimensional van der Waals field emitters have been observed and predicted since the landmark discovery of graphene. Due to the wide variety of heterostructures that integrate an atomic monolayer or multilayers with insulator nanofilms or metallic cathodes by van der Waals force, the diversity of van der Waals materials is large to be chosen from, which are appealing for further investigation. Until now, increasing the efficiency, stability, and uniformity in electron emission of cold cathodes with two-dimensional materials is still of interest in research. Some novel behaviors in electron emission, such as coherence and directionality, have been revealed by the theoretical study down to the atomic scale and could lead to innovative applications. Although intensive emission in the direction normal to two-dimensional emitters has been observed in experiments, the theoretical mechanism is still incomplete. In this paper, we will review some late progresses related to the cold cathodes with two-dimensional van der Waals materials, both in experiments and in the theoretical study, emphasizing the phenomena which are absent in the conventional cold cathodes. The review will cover the fabrication of several kinds of emitter structures for field emission applications, the state of the art of their field emission properties and the existing field emission model. In the end, some perspectives on their future research trend will also be given.
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Affiliation(s)
- Yicong Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technologies, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technologies, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zhibing Li
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Science, Sun Yat-Sen University, Shenzhen 518000, China
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3
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Avotina L, Bikse L, Dekhtyar Y, Goldmane AE, Kizane G, Muhin A, Romanova M, Smits K, Sorokins H, Vilken A, Zaslavskis A. Tungsten-SiO 2-Based Planar Field Emission Microtriodes with Different Electrode Topologies. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5781. [PMID: 37687474 PMCID: PMC10488438 DOI: 10.3390/ma16175781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/14/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023]
Abstract
This study examines the electrical properties and layer quality of field emission microtriodes that have planar electrode geometry and are based on tungsten (W) and silicon dioxide (SiO2). Two types of microtriodes were analyzed: one with a multi-tip cathode fabricated using photolithography (PL) and the other with a single-tip cathode fabricated using a focused ion beam (FIB). Atomic force microscopy (AFM) analysis revealed surface roughness of the W layer in the order of several nanometers (Ra = 3.8 ± 0.5 nm). The work function values of the Si substrate, SiO2 layer, and W layer were estimated using low-energy ultraviolet photoelectron emission (PE) spectroscopy and were 4.71 eV, 4.85 eV, and 4.67 eV, respectively. The homogeneity of the W layer and the absence of oxygen and silicon impurities were confirmed via X-ray photoelectron spectroscopy (XPS). The PL microtriode and the FIB microtriode exhibited turn-on voltages of 110 V and 50 V, respectively, both demonstrating a field emission current of 0.4 nA. The FIB microtriode showed significantly improved field emission efficiency compared to the PL microtriode, attributed to a higher local electric field near the cathode.
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Affiliation(s)
- Liga Avotina
- Institute of Chemical Physics, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (L.A.); (A.E.G.); (G.K.)
| | - Liga Bikse
- Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga, Latvia; (L.B.); (K.S.)
| | - Yuri Dekhtyar
- Institute of Biomedical Engineering and Nanotechnologies, Riga Technical University, 6B Kipsalas Street, LV-1048 Riga, Latvia; (M.R.); (H.S.); (A.V.)
| | - Annija Elizabete Goldmane
- Institute of Chemical Physics, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (L.A.); (A.E.G.); (G.K.)
| | - Gunta Kizane
- Institute of Chemical Physics, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (L.A.); (A.E.G.); (G.K.)
| | - Aleksei Muhin
- Joint Stock Company “ALFA RPAR”, 140 Ropazu Street, LV-1006 Riga, Latvia
| | - Marina Romanova
- Institute of Biomedical Engineering and Nanotechnologies, Riga Technical University, 6B Kipsalas Street, LV-1048 Riga, Latvia; (M.R.); (H.S.); (A.V.)
| | - Krisjanis Smits
- Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga, Latvia; (L.B.); (K.S.)
| | - Hermanis Sorokins
- Institute of Biomedical Engineering and Nanotechnologies, Riga Technical University, 6B Kipsalas Street, LV-1048 Riga, Latvia; (M.R.); (H.S.); (A.V.)
| | - Aleksandr Vilken
- Institute of Biomedical Engineering and Nanotechnologies, Riga Technical University, 6B Kipsalas Street, LV-1048 Riga, Latvia; (M.R.); (H.S.); (A.V.)
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MoS2-Cu/CuO@graphene Heterogeneous Photocatalysis for Enhanced Photocatalytic Degradation of MB from Water. Polymers (Basel) 2022; 14:polym14163259. [PMID: 36015522 PMCID: PMC9414561 DOI: 10.3390/polym14163259] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/24/2022] [Accepted: 08/04/2022] [Indexed: 12/29/2022] Open
Abstract
The industrial revolution resulted in the contamination of natural water resources. Therefore, it is necessary to save and recover the natural water resources. In this regard, polymer-based composites have attracted the scientific community for their application in wastewater treatment. Herein, molybdenum disulfide composites with a mix phase of copper, copper oxide and graphene (MoS2-Cu/CuO@GN) were synthesized through the hydrothermal method. Methylene blue (MB) was degraded by around 93.8% within the 30 min in the presence of MoS2-Cu/CuO@GN under visible light. The degradation efficiency was further enhanced to 98.5% with the addition of H2O2 as a catalyst. The photocatalytic degradation efficiency of pure MoS2, MoS2-Cu/CuO and MoS2-Cu/CuO@GN were also investigated under the same experimental conditions. The structural analysis endorses the presence of the Cu/CuO dual phase in MoS2. The charge recombination ratio and band gap of MoS2-Cu/CuO@GN were also investigated in comparison to pure MoS2 and MoS2-Cu/CuO. The chemical states, the analysis of C1s, O1s, Mo3d and Cu2p3, were also analyzed to explore the possible interaction among the present elements. The surface morphology confirms the existence of Cu/CuO and GN to MoS2.
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Superconducting- and Graphene-Based Devices. NANOMATERIALS 2022; 12:nano12122055. [PMID: 35745392 PMCID: PMC9229232 DOI: 10.3390/nano12122055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 12/10/2022]
Abstract
This Special Issue has been organized to collect new or improved ideas regarding the exploitation of superconducting materials, as well as graphene, aiming to develop innovative devices [...].
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Helal MA, El-Sayed HM, Maarouf AA, Fadlallah MM. Metal dichalcogenide nanomeshes: structural, electronic and magnetic properties. Phys Chem Chem Phys 2021; 23:21183-21195. [PMID: 34528957 DOI: 10.1039/d1cp03743a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motivated by the successful preparation of two-dimensional transition metal dichalcogenide (2D-TMD) nanomeshes in the last three years, we use density functional theory (DFT) to study the structural stability, mechanical, magnetic, and electronic properties of porous 2H-MoX2 (X = S, Se and Te) without and with pore passivation. We consider structures with multiple, systematically created pores. The molecular dynamics simulations and cohesive energy calculations showed the stability of the 2D-TMD nanomeshes, with larger stability for those with smaller pores. The lattice undergoes some deformations to accommodate the pore energetically, and as the pore size increases Young's modulus decreases. In most cases, the missing metal atoms disrupt the spin states' even population, resulting in some nanomeshes becoming magnetic. The electronic gaps of the MoX2 nanomesh systems are diminished because of the emergence of pore-edge localized mid-gap metal 4d states in the spin-polarized spectrum, making some systems half-metallic. The oxygen passivation of the pore edges of 2D-TMD nanomeshes restores the even population of spin states, and makes those systems metallic. Our results can be used in different applications such as spintronics, ion chelation, and molecular sensing applications.
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Affiliation(s)
- Mohamed A Helal
- Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
| | - H M El-Sayed
- Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
| | - Ahmed A Maarouf
- Department of Physics, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia.
| | - Mohamed M Fadlallah
- Department of Physics, Faculty of Science, Benha University, Benha 13518, Egypt.
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Giubileo F, Bartolomeo AD, Zhong Y, Zhao S, Passacantando M. Field emission from AlGaN nanowires with low turn-on field. NANOTECHNOLOGY 2020; 31:475702. [PMID: 32885788 DOI: 10.1088/1361-6528/abaf22] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We fabricate AlGaN nanowires by molecular beam epitaxy and we investigate their field emission properties by means of an experimental setup using nano-manipulated tungsten tips as electrodes, inside a scanning electron microscope. The tip-shaped anode gives access to local properties, and allows collecting electrons emitted from areas as small as 1 µm2. The field emission characteristics are analysed in the framework of Fowler-Nordheim theory and we find a field enhancement factor as high as β = 556 and a minimum turn-on field [Formula: see text] = 17 V µm-1 for a cathode-anode separation distance [Formula: see text] = 500 nm. We show that for increasing separation distance, [Formula: see text] increases up to about 35 V µm-1 and β decreases to ∼100 at [Formula: see text] = 1600 nm. We also demonstrate the time stability of the field emission current from AlGaN nanowires for several minutes. Finally, we explain the observation of modified slope of the Fowler-Nordheim plots at low fields in terms of non-homogeneous field enhancement factors due to the presence of protruding emitters.
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Affiliation(s)
- Filippo Giubileo
- CNR-SPIN Salerno, via Giovanni Paolo II n. 132, Fisciano 84084, Italy
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8
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Pelella A, Kharsah O, Grillo A, Urban F, Passacantando M, Giubileo F, Iemmo L, Sleziona S, Pollmann E, Madauß L, Schleberger M, Di Bartolomeo A. Electron Irradiation of Metal Contacts in Monolayer MoS 2 Field-Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2020; 12:40532-40540. [PMID: 32805860 PMCID: PMC8153392 DOI: 10.1021/acsami.0c11933] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/10/2020] [Indexed: 05/08/2023]
Abstract
Metal contacts play a fundamental role in nanoscale devices. In this work, Schottky metal contacts in monolayer molybdenum disulfide (MoS2) field-effect transistors are investigated under electron beam irradiation. It is shown that the exposure of Ti/Au source/drain electrodes to an electron beam reduces the contact resistance and improves the transistor performance. The electron beam conditioning of contacts is permanent, while the irradiation of the channel can produce transient effects. It is demonstrated that irradiation lowers the Schottky barrier at the contacts because of thermally induced atom diffusion and interfacial reactions. The simulation of electron paths in the device reveals that most of the beam energy is absorbed in the metal contacts. The study demonstrates that electron beam irradiation can be effectively used for contact improvement through local annealing.
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Affiliation(s)
- Aniello Pelella
- Department
of Physics and Interdepartmental Centre NanoMates, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
- CNR-SPIN, via Giovanni Paolo II, Fisciano 84084, Italy
| | - Osamah Kharsah
- Fakultät
für Physik and CENIDE, Universität
Duisburg-Essen, Lotharstrasse
1, Duisburg 47057, Germany
| | - Alessandro Grillo
- Department
of Physics and Interdepartmental Centre NanoMates, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
- CNR-SPIN, via Giovanni Paolo II, Fisciano 84084, Italy
| | - Francesca Urban
- Department
of Physics and Interdepartmental Centre NanoMates, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
- CNR-SPIN, via Giovanni Paolo II, Fisciano 84084, Italy
- INFN—Gruppo
Collegato di Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
| | - Maurizio Passacantando
- Department
of Physical and Chemical Sciences, University
of L’Aquila, and CNR-SPIN L’Aquila, via Vetoio, Coppito, L’Aquila 67100, Italy
| | | | - Laura Iemmo
- Department
of Physics and Interdepartmental Centre NanoMates, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
- CNR-SPIN, via Giovanni Paolo II, Fisciano 84084, Italy
| | - Stephan Sleziona
- Fakultät
für Physik and CENIDE, Universität
Duisburg-Essen, Lotharstrasse
1, Duisburg 47057, Germany
| | - Erik Pollmann
- Fakultät
für Physik and CENIDE, Universität
Duisburg-Essen, Lotharstrasse
1, Duisburg 47057, Germany
| | - Lukas Madauß
- Fakultät
für Physik and CENIDE, Universität
Duisburg-Essen, Lotharstrasse
1, Duisburg 47057, Germany
| | - Marika Schleberger
- Fakultät
für Physik and CENIDE, Universität
Duisburg-Essen, Lotharstrasse
1, Duisburg 47057, Germany
| | - Antonio Di Bartolomeo
- Department
of Physics and Interdepartmental Centre NanoMates, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
- CNR-SPIN, via Giovanni Paolo II, Fisciano 84084, Italy
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Urban F, Lupina G, Grillo A, Martucciello N, Di Bartolomeo A. Contact resistance and mobility in back-gate graphene transistors. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/ab7055] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
The metal-graphene contact resistance is one of the major limiting factors toward the technological exploitation of graphene in electronic devices and sensors. High contact resistance can be detrimental to device performance and spoil the intrinsic great properties of graphene. In this paper, we fabricate back-gate graphene field-effect transistors with different geometries to study the contact and channel resistance as well as the carrier mobility as a function of gate voltage and temperature. We apply the transfer length method and the y-function method showing that the two approaches can complement each other to evaluate the contact resistance and prevent artifacts in the estimation of carrier mobility dependence on the gate-voltage. We find that the gate voltage modulates both the contact and the channel resistance in a similar way but does not change the carrier mobility. We also show that raising the temperature lowers the carrier mobility, has a negligible effect on the contact resistance, and can induce a transition from a semiconducting to a metallic behavior of the graphene sheet resistance, depending on the applied gate voltage. Finally, we show that eliminating the detrimental effects of the contact resistance on the transistor channel current almost doubles the carrier field-effect mobility and that a competitive contact resistance as low as 700 Ω·μm can be achieved by the zig-zag shaping of the Ni contact.
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Feng Y, Du E, Gong S, Yu K, Chen X, Zhu Z. Synthesis of a finger-like MoS 2@VS 2 micro–nanocomposite with enhanced field emission performance. CrystEngComm 2020. [DOI: 10.1039/d0ce00347f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A MoS2@VS2 micro–nanocomposite showed enhanced field emission properties benefiting from the synergy of the two materials.
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Affiliation(s)
- Yu Feng
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
| | - Erwei Du
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
| | - Shijing Gong
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
| | - Ke Yu
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
| | - Xiaofan Chen
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
| | - Ziqiang Zhu
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China)
- Department of Electronics
- East China Normal University
- Shanghai 200241
- China
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