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Giubileo F, Faella E, Capista D, Passacantando M, Durante O, Kumar A, Pelella A, Intonti K, Viscardi L, De Stefano S, Martucciello N, Craciun MF, Russo S, Di Bartolomeo A. Field enhancement induced by surface defects in two-dimensional ReSe 2 field emitters. NANOSCALE 2024; 16:16718-16728. [PMID: 39172122 DOI: 10.1039/d4nr02109f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
The field emission properties of rhenium diselenide (ReSe2) nanosheets on Si/SiO2 substrates, obtained through mechanical exfoliation, have been investigated. The n-type conduction was confirmed by using nano-manipulated tungsten probes inside a scanning electrode microscope to directly contact the ReSe2 flake in back-gated field effect transistor configuration, avoiding any lithographic process. By performing a finite element electrostatic simulation of the electric field, it is demonstrated that the use of a tungsten probe as anode, at a controlled distance from the ReSe2 emitter surface, allows the collection of emitted electrons from a reduced area that furtherly decreases by reducing the tip-sample distance, i.e. allowing a local characterization of the field emission properties. Experimentally, it is shown that the turn-on voltage can be linearly reduced by reducing the cathode-anode separation distance. By comparing the measured current-voltage characteristics with the numerical simulations, it is also shown that the effective field enhancement on the emitter surface is larger than expected because of surface defects. Finally, it is confirmed that ReSe2 nanosheets are suitable field emitters with high time stability and low current fluctuations.
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Affiliation(s)
- Filippo Giubileo
- CNR-SPIN Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | - Enver Faella
- Department of Physical and Chemical Science, University of L'Aquila, Via Vetoio, Coppito, 67100 L'Aquila, Italy
| | - Daniele Capista
- IHP-Leibnitz Institut fuer innovative Mikroelektronik, 15236 Frankfurt (Oder), Germany
| | - Maurizio Passacantando
- Department of Physical and Chemical Science, University of L'Aquila, Via Vetoio, Coppito, 67100 L'Aquila, Italy
| | - Ofelia Durante
- CNR-SPIN Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | - Arun Kumar
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | - Aniello Pelella
- Dipartimento di Fisica, Università degli studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Kimberly Intonti
- CNR-SPIN Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | - Loredana Viscardi
- CNR-SPIN Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | - Sebastiano De Stefano
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
| | | | | | - Saverio Russo
- University of Exeter, Stocker Road 6, Exeter EX4 4QL, Devon, UK
| | - Antonio Di Bartolomeo
- CNR-SPIN Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
- Department of Physics "E.R. Caianiello", University of Salerno, via Giovanni Paolo II n.132, 84084 Fisciano, Italy.
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Kumar P, Parashar M, Chauhan K, Chakraborty N, Sarkar S, Chandra A, Das NS, Chattopadhyay KK, Ghoari A, Adalder A, Ghorai UK, Saini S, Agarwal D, Ghosh S, Srivastava P, Banerjee D. Significant enhancement in the cold emission characteristics of chemically synthesized super-hydrophobic zinc oxide rods by nickel doping. NANOSCALE ADVANCES 2023; 5:6944-6957. [PMID: 38059027 PMCID: PMC10696928 DOI: 10.1039/d3na00776f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 10/28/2023] [Indexed: 12/08/2023]
Abstract
The current article presents a huge enhancement in the field emission characteristics of zinc oxide (ZnO) micro/nanorods by nickel doping. The synthesis of pure and nickel-doped zinc oxide (ZnO) micro/nanorods was done by a simple low-temperature chemical method. Both the as-prepared pure and doped samples were analyzed by X-ray diffraction and electron microscopy to confirm the proper phase formation and the developed microstructure. UV-vis transmittance spectra helped in determining the band gap of the samples. Fourier-Transform Infrared Spectroscopy (FTIR) spectra showed the different bonds present in the sample, whereas X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of nickel in the doped sample. Photoluminescence (PL) spectra showed that after doping, the band-to-band transition was affected, whereas defect-induced transition had increased significantly. After the nickel doping, contact angle measurement revealed a significant decrease in the sample's surface energy, leading to a remarkably high water contact angle (within the superhydrophobic region). Simulation through ANSYS suggested that the doped sample has the potential to function as an efficient cold emitter, which was also verified experimentally. The cold emission characteristics of the doped sample showed a significant improvement, with the turn-on field (corresponding to J = 1 μA cm-2) reduced from 5.34 to 2.84 V μm-1. The enhancement factor for the doped sample reached 3426, approximately 1.5 times higher compared to pure ZnO. Efforts have been made to explain the results, given the favorable band bending as well as the increased number of effective emission sites.
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Affiliation(s)
- P Kumar
- Thin Film and Nanotechnology Laboratory, Faculty of Engineering and Computing Sciences, Teerthanker Mahaveer University Moradabad UP 244001 India
| | - M Parashar
- Thin Film and Nanotechnology Laboratory, Faculty of Engineering and Computing Sciences, Teerthanker Mahaveer University Moradabad UP 244001 India
| | - K Chauhan
- Thin Film and Nanotechnology Laboratory, Faculty of Engineering and Computing Sciences, Teerthanker Mahaveer University Moradabad UP 244001 India
| | - N Chakraborty
- Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University Kolkata West Bengal 700032 India
| | - S Sarkar
- Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University Kolkata West Bengal 700032 India
| | - A Chandra
- Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University Kolkata West Bengal 700032 India
| | - N S Das
- Department of Basic Science and Humanities, Techno International Batanagar Maheshtala Kolkata 700141 India
| | - K K Chattopadhyay
- Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University Kolkata West Bengal 700032 India
| | - A Ghoari
- Department of Industrial Chemistry, Ramakrishna Mission Vidyamandira Belur Math Howrah-711202 India
| | - A Adalder
- Department of Industrial Chemistry, Ramakrishna Mission Vidyamandira Belur Math Howrah-711202 India
| | - U K Ghorai
- Department of Industrial Chemistry, Ramakrishna Mission Vidyamandira Belur Math Howrah-711202 India
| | - S Saini
- Department of Physics, Indian Institute of Technology Hauz Khas South West Delhi 110016 India
| | - D Agarwal
- Department of Physics, Indian Institute of Technology Hauz Khas South West Delhi 110016 India
| | - S Ghosh
- Department of Physics, Indian Institute of Technology Hauz Khas South West Delhi 110016 India
| | - P Srivastava
- Department of Physics, Indian Institute of Technology Hauz Khas South West Delhi 110016 India
| | - D Banerjee
- Thin Film and Nanotechnology Laboratory, Faculty of Engineering and Computing Sciences, Teerthanker Mahaveer University Moradabad UP 244001 India
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Zhang S, Cao X, Zhang G, Deng S, Chen J. Optimizing Performance of Coaxis Planar-Gated ZnO Nanowire Field-Emitter Arrays by Tuning Pixel Density. NANOMATERIALS 2022; 12:nano12050870. [PMID: 35269358 PMCID: PMC8912392 DOI: 10.3390/nano12050870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 02/01/2023]
Abstract
Gated ZnO nanowire field emitter arrays (FEAs) have important applications in large-area vacuum microelectronic devices such as flat panel X-ray sources and photodetectors. As the application requires high-pixel-density FEAs, how the pixel density affects the emission performance of the gated ZnO nanowire FEAs needs investigating. In this paper, the performance of coaxis planar -gated ZnO nanowire FEAs was simulated under different pixel sizes while keeping the lateral geometric parameter in proportion. The variations in emission current and gate modulation with pixel size were obtained. Using the obtained device parameters, the coaxis planar-gated ZnO nanowire FEAs were prepared. Field emission measurement results showed that a current density of 3.2 mA/cm2 was achieved from the fabricated ZnO nanowire FEAs when the gate voltage was 140 V. A transconductance of 253 nS was obtained, indicating effective gate control. The improved performance is attributed to optimized gate modulation.
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Chen Y, Deng S, Xu N, Chen J. Recent Progress on ZnO Nanowires Cold Cathode and Its Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2150. [PMID: 34443983 PMCID: PMC8400790 DOI: 10.3390/nano11082150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 01/09/2023]
Abstract
A cold cathode has many applications in high frequency and high power electronic devices, X-ray source, vacuum microelectronic devices and vacuum nanoelectronic devices. After decades of exploration on the cold cathode materials, ZnO nanowire has been regarded as one of the most promising candidates, in particular for large area field emitter arrays (FEAs). Numerous works on the fundamental field emission properties of ZnO nanowire, as well as demonstrations of varieties of large area vacuum microelectronic applications, have been reported. Moreover, techniques such as modifying the geometrical structure, surface decoration and element doping were also proposed for optimizing the field emissions. This paper aims to provide a comprehensive review on recent progress on the ZnO nanowire cold cathode and its applications. We will begin with a brief introduction on the synthesis methods and discuss their advantages/disadvantages for cold cathode applications. After that, the field emission properties, mechanism and optimization will be introduced in detail. Then, the development for applications of large-area ZnO nanowire FEAs will also be covered. Finally, some future perspectives are provided.
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Affiliation(s)
| | | | | | - Jun Chen
- State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Lab of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China; (Y.C.); (S.D.); (N.X.)
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Wang L, Wei Y, Chen C, Yang S. One-dimensional ZnO micro/nanostructures: deep insight into the growth mechanism and fine control of the microscopic morphology. Dalton Trans 2021; 50:3011-3019. [PMID: 33566036 DOI: 10.1039/d1dt00127b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
One-dimensional zinc oxide arrays with various finely controlled microscopic morphologies are grown on fluorine-doped tin oxide substrates by a hydrothermal method. The relationship between the microscopic morphologies and the reaction conditions are studied deeply. It is found that although all the studied reaction parameters, like reaction time, pH value, concentration of the reactants and so on, can affect the microstructures of the resultant products, what they affect, in essence, is the concentration of free Zn2+ ions of the solution. By exploring the evolution of the microstructure of the one-dimensional zinc oxide crystals, it is proved that the formation of the various microscopic morphologies is a result of the competition between the kinetic control and the thermodynamic control during the crystal growth, which in turn is mainly determined by the concentration of the free Zn2+ ions in the solution. The in-depth exploration of the growth mechanism of zinc oxide and the fine control of its microscopic morphologies is expected to provide advanced materials for current and future cutting-edge applications of zinc oxide. It is also expected that the growth mechanism reported here can provide theoretical support for achieving other oxide materials whose microstructure can be finely controlled.
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Affiliation(s)
- Leshuang Wang
- School of Chemistry and Chemical Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan, 250022, Shandong, PR China.
| | - Yuling Wei
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology (Shandong Academy of Sciences), No. 3501, Daxue Road, Changqing District, Jinan 250353, Shandong, PR China.
| | - Changlong Chen
- School of Chemistry and Chemical Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan, 250022, Shandong, PR China.
| | - Shu Yang
- School of Chemistry and Chemical Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan, 250022, Shandong, PR China.
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Zhao Y, Chen Y, Zhang G, Zhan R, She J, Deng S, Chen J. High Current Field Emission from Large-Area Indium Doped ZnO Nanowire Field Emitter Arrays for Flat-Panel X-ray Source Application. NANOMATERIALS 2021; 11:nano11010240. [PMID: 33477592 PMCID: PMC7831334 DOI: 10.3390/nano11010240] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 02/01/2023]
Abstract
Large-area zinc oxide (ZnO) nanowire arrays have important applications in flat-panel X-ray sources and detectors. Doping is an effective way to enhance the emission current by changing the nanowire conductivity and the lattice structure. In this paper, large-area indium-doped ZnO nanowire arrays were prepared on indium-tin-oxide-coated glass substrates by the thermal oxidation method. Doping with indium concentrations up to 1 at% was achieved by directly oxidizing the In-Zn alloy thin film. The growth process was subsequently explained using a self-catalytic vapor-liquid-solid growth mechanism. The field emission measurements show that a high emission current of ~20 mA could be obtained from large-area In-doped sample with a 4.8 × 4.8 cm2 area. This high emission current was attributed to the high crystallinity and conductivity change induced by the indium dopants. Furthermore, the application of these In-doped ZnO nanowire arrays in a flat-panel X-ray source was realized and distinct X-ray imaging was demonstrated.
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Zhang D, Zhang S, He K, Wang L, Sui F, Hong X, Li W, Li N, Jia M, Li W, Wang Z, Wang Z, Du B, Wei L, Feng Y, Zhong G, Li W, Chen J, Yang C, Chen M. High-performance x-ray source based on graphene oxide-coated Cu 2S nanowires grown on copper film. NANOTECHNOLOGY 2020; 31:485202. [PMID: 32931468 DOI: 10.1088/1361-6528/abb0b6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Full static x-ray computed tomography (CT) technology has enabled higher precision and resolution imaging and has been applied in many applications such as diagnostic medical imaging, industrial inspection and security screening. In this technique, the x-ray source section is mainly composed of a thermionic cathode and electron beam scanning system. However, they have several shortcomings such as limited scanning angle, long response time and large volume. Distributed and programmable cold cathode (i.e. carbon nanotubes, ZnO nanowires (NWs)) field-emission x-ray sources are expected to solve these problems. However, there have been several long-standing challenges to the application of such cold field emitters for x-ray sources, such as the short lifetime and rigorous fabrication process, which have fundamentally prevented their widespread use. Here, we propose and demonstrate a cold field-emission x-ray source based on a graphene oxide (GO)-coated cuprous sulfide nanowire (Cu2S NW/GO) cathode. The proposed Cu2S NW/GO x-ray source provides stable emission (>18 h at a direct voltage of 2600 V) and has a low threshold (4.5 MV m-1 for obtaining a current density of 1 μA cm-2), benefiting from the demonstrated key features such as in situ epitaxy growth of Cu2S NWs on Cu, nanometer-scale sharp protrusions within GO and charge transfer between the Cu2S NWs and GO layer. Our research provides a simple and robust method to obtain a high-performance cold field emitter, leading to great potential for the next generation of x-ray source and CT.
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Affiliation(s)
- Daoshu Zhang
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China
| | - Siyuan Zhang
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China
| | - Ke He
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China
| | - Libin Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China
| | - Fan Sui
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Xuda Hong
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Weiwei Li
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China
| | - Nianci Li
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Meiling Jia
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People's Republic of China
| | - Weimin Li
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Zhixun Wang
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Zongpeng Wang
- Shenzhen Angell Technology Co. Ltd., Shenzhen 518057, People's Republic of China
| | - Bi Du
- Shenzhen Angell Technology Co. Ltd., Shenzhen 518057, People's Republic of China
| | - Lei Wei
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Ye Feng
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Guohua Zhong
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Wenjie Li
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Jun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China
| | - Chunlei Yang
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Ming Chen
- Center for Information Photonics and Energy Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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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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Zhao P, Zhang Y, Tang S, Zhan R, She J, Chen J, Deng S. A Universal Method to Weld Individual One-Dimensional Nanostructures with a Tungsten Needle Based on Synergy of the Electron Beam and Electrical Current. NANOMATERIALS 2020; 10:nano10030469. [PMID: 32150896 PMCID: PMC7153624 DOI: 10.3390/nano10030469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 01/14/2023]
Abstract
One-dimensional (1D) nanostructures are extensively used in the design of novel electronic devices, sensors, and energy devices. One of the major challenges faced by the electronics industry is the problem of contact between the 1D nanostructure and electrode, which can limit or even jeopardize device operations. Herein, a universal method that can realize good Ohmic and mechanical contact between an individual 1D nanostructure and a tungsten needle at sub-micron or micron scale is investigated and presented in a scanning electron microscope (SEM) chamber with the synergy of an electron beam and electrical current flowing through the welded joint. The linear I‒V curves of five types of individual 1D nanostructures, characterized by in-situ electrical measurements, demonstrate that most of them demonstrate good Ohmic contact with the tungsten needle, and the results of in-situ tensile measurements demonstrate that the welded joints possess excellent mechanical performance. By simulation analysis using the finite element method, it is proved that the local heating effect, which is mainly produced by the electrical current flowing through the welded joints during the welding process, is the key factor in achieving good Ohmic contact.
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Zhou S, Chen K, Cole MT, Li Z, Chen J, Li C, Dai Q. Ultrafast Field-Emission Electron Sources Based on Nanomaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805845. [PMID: 30724407 DOI: 10.1002/adma.201805845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 11/29/2018] [Indexed: 06/09/2023]
Abstract
The search for electron sources with simultaneous optimal spatial and temporal resolution has become an area of intense activity for a wide variety of applications in the emerging fields of lightwave electronics and attosecond science. Most recently, increasing efforts are focused on the investigation of ultrafast field-emission phenomena of nanomaterials, which not only are fascinating from a fundamental scientific point of view, but also are of interest for a range of potential applications. Here, the current state-of-the-art in ultrafast field-emission, particularly sub-optical-cycle field emission, based on various nanostructures (e.g., metallic nanotips, carbon nanotubes) is reviewed. A number of promising nanomaterials and possible future research directions are also established.
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Affiliation(s)
- Shenghan Zhou
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
| | - Ke Chen
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
| | - Matthew Thomas Cole
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhenjun Li
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
| | - Jun Chen
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Chi Li
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
| | - Qing Dai
- Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese, Academy of Sciences, Beijing, 100049, P. R. China
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Lin Z, Zhan R, Chen Y, She J, Deng S, Xu N, Chen J. Defective WO 3-x nanowire: possible long lifetime semiconductor nanowire point electron source. NANOSCALE 2019; 11:3370-3377. [PMID: 30724951 DOI: 10.1039/c8nr08984a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In pursuing high emission current density and high brightness, it is difficult to avoid vacuum breakdown in nanowire cold cathode systems, which will shorten the lifetime of the electron sources. Therefore, investigations on the vacuum breakdown process are important for semiconductor nanowire point electron sources. In this study, non-catastrophic breakdown phenomena that could extend the lifetime of the nanowire electron source were observed in the field emission processes of individual defective WO3-x nanowires. In this non-catastrophic breakdown process, only part of the nanowire emitter was destroyed. After the breakdown, the remaining part of the nanowire could still emit electrons, and due to the shortening of its length, the maximum field emission current density of the remaining nanowire was increased. These results are consistent with the prediction given by theoretical calculations. A defect-related electrical transport induced breakdown mechanism and Nottingham effect induced cooling effect were proposed to be the main causes of this phenomenon. Our work provides an approach for designing long lifetime semiconductor nanowire point electron sources.
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Affiliation(s)
- Zufang Lin
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275 China.
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Coplanar-gate ZnO nanowire field emitter arrays with enhanced gate-control performance using a ring-shaped cathode. Sci Rep 2018; 8:12294. [PMID: 30116023 PMCID: PMC6095927 DOI: 10.1038/s41598-018-30279-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/26/2018] [Indexed: 11/09/2022] Open
Abstract
Nanowire field emitters have great potential for use as large-area gated field emitter arrays (FEAs). However, the micrometer-scale cathode patterns in gated FEA devices will reduce regulation of the gate voltage and limit the field emission currents of these devices as a result of field-screening effect among the neighboring nanowires. In this article, a ring-shaped ZnO nanowire pad is proposed to overcome this problem. Diode measurements show that the prepared ring-shaped ZnO nanowire pad arrays shows uniform emission with a turn-on field of 5.9 V/µm and a field emission current density of 4.6 mA/cm2 under an applied field of 9 V/µm. The ZnO nanowire pad arrays were integrated into coplanar-gate FEAs and enhanced gate-controlled device characteristics were obtained. The gate-controlled capability was studied via microscopic in-situ measurements of the field emission from the ZnO nanowires in the coplanar-gate FEAs. Based on the results of both simulations and experiments, we attributed the enhanced gate-controlled device capabilities to more efficient emission of electrons from the ZnO nanowires as a result of the increase edge area by designing ring-shaped ZnO nanowire pad. The results are important to the realization of large-area gate-controlled FEAs based on nanowire emitters for use in vacuum electronic devices.
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14
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Park S, Gupta AP, Yeo SJ, Jung J, Paik SH, Mativenga M, Kim SH, Shin JH, Ahn JS, Ryu J. Carbon Nanotube Field Emitters Synthesized on Metal Alloy Substrate by PECVD for Customized Compact Field Emission Devices to Be Used in X-Ray Source Applications. NANOMATERIALS 2018; 8:nano8060378. [PMID: 29843456 PMCID: PMC6027437 DOI: 10.3390/nano8060378] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/21/2018] [Accepted: 05/24/2018] [Indexed: 11/16/2022]
Abstract
In this study, a simple, efficient, and economical process is reported for the direct synthesis of carbon nanotube (CNT) field emitters on metal alloy. Given that CNT field emitters can be customized with ease for compact and cold field emission devices, they are promising replacements for thermionic emitters in widely accessible X-ray source electron guns. High performance CNT emitter samples were prepared in optimized plasma conditions through the plasma-enhanced chemical vapor deposition (PECVD) process and subsequently characterized by using a scanning electron microscope, tunneling electron microscope, and Raman spectroscopy. For the cathode current, field emission (FE) characteristics with respective turn on (1 μA/cm²) and threshold (1 mA/cm²) field of 2.84 and 4.05 V/μm were obtained. For a field of 5.24 V/μm, maximum current density of 7 mA/cm² was achieved and a field enhancement factor β of 2838 was calculated. In addition, the CNT emitters sustained a current density of 6.7 mA/cm² for 420 min under a field of 5.2 V/μm, confirming good operational stability. Finally, an X-ray generated image of an integrated circuit was taken using the compact field emission device developed herein.
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Affiliation(s)
- Sangjun Park
- Department of Physics, Kyung Hee University, Seoul 02453, Korea; (S.P.); (A.P.G.); (S.J.Y.)
| | - Amar Prasad Gupta
- Department of Physics, Kyung Hee University, Seoul 02453, Korea; (S.P.); (A.P.G.); (S.J.Y.)
- CAT Beam Tech Co., Ltd., Seoul Biohub, 117-3, Hoegi-ro, Dongdaemun-gu, Seoul 02455, Korea; (J.J.); (S.H.P.)
| | - Seung Jun Yeo
- Department of Physics, Kyung Hee University, Seoul 02453, Korea; (S.P.); (A.P.G.); (S.J.Y.)
- CAT Beam Tech Co., Ltd., Seoul Biohub, 117-3, Hoegi-ro, Dongdaemun-gu, Seoul 02455, Korea; (J.J.); (S.H.P.)
| | - Jaeik Jung
- CAT Beam Tech Co., Ltd., Seoul Biohub, 117-3, Hoegi-ro, Dongdaemun-gu, Seoul 02455, Korea; (J.J.); (S.H.P.)
| | - Sang Hyun Paik
- CAT Beam Tech Co., Ltd., Seoul Biohub, 117-3, Hoegi-ro, Dongdaemun-gu, Seoul 02455, Korea; (J.J.); (S.H.P.)
- Department of Radiology, Vinmec International Hospital, Ha Noi 10000, Vietnam
| | - Mallory Mativenga
- Department of Information Display, Kyung Hee University, Seoul 02453, Korea;
| | - Seung Hoon Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea; (S.H.K.); (J.H.S.)
| | - Ji Hoon Shin
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea; (S.H.K.); (J.H.S.)
| | - Jeung Sun Ahn
- Department of Physics, Kyung Hee University, Seoul 02453, Korea; (S.P.); (A.P.G.); (S.J.Y.)
- Correspondence: (J.S.A.); (J.R.); Tel.: + 82-2-959-2016 (J.R.)
| | - Jehwang Ryu
- Department of Physics, Kyung Hee University, Seoul 02453, Korea; (S.P.); (A.P.G.); (S.J.Y.)
- CAT Beam Tech Co., Ltd., Seoul Biohub, 117-3, Hoegi-ro, Dongdaemun-gu, Seoul 02455, Korea; (J.J.); (S.H.P.)
- Correspondence: (J.S.A.); (J.R.); Tel.: + 82-2-959-2016 (J.R.)
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15
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Maximum field emission current density of CuO nanowires: theoretical study using a defect-related semiconductor field emission model and in situ measurements. Sci Rep 2018; 8:2131. [PMID: 29391554 PMCID: PMC5794980 DOI: 10.1038/s41598-018-20575-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/22/2018] [Indexed: 11/08/2022] Open
Abstract
In this study, we proposed a theoretical model for one-dimensional semiconductor nanowires (NWs), taking account of the defect-related electrical transport process. The maximum emission current density was calculated by considering the influence of Joule heating, using a one-dimensional heat equation. The field emission properties of individual CuO NWs with different electrical properties were studied using an in situ experimental technique. The experimental results for maximum emission current density agreed well with the theoretical predictions and suggested that multiple conduction mechanisms were active. These may be induced by the concentration of defects in the CuO NW. The concentration of defects and the transport mechanisms were found to be key factors influencing the maximum field emission current density of the semiconductor NW. As is limited by the change of resistivity with temperature, only thermal runaway can trigger breakdown in CuO NWs.
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16
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Ma LA, Wei ZH. Effect of synthesis conditions on the morphology and field-emission properties of hydrothermally grown Zn-doped SnO2 nanorods. CrystEngComm 2018. [DOI: 10.1039/c7ce02236k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zn–SnO2 nanorod arrays with various sizes and aspect ratios on a Cu substrate have been achieved and the sword-like nanorod arrays have the lowest Eon of ∼2.75 V μm−1 and the highest β of ∼1970.
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Affiliation(s)
- L. A. Ma
- School of Materials Science and Engineering
- Fujian University of Technology
- Fuzhou
- PR China
| | - Z. H. Wei
- School of Materials Science and Engineering
- Fujian University of Technology
- Fuzhou
- PR China
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17
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Liu Y, Jiang M, He G, Li S, Zhang Z, Li B, Zhao H, Shan C, Shen D. Wavelength-Tunable Ultraviolet Electroluminescence from Ga-Doped ZnO Microwires. ACS APPLIED MATERIALS & INTERFACES 2017; 9:40743-40751. [PMID: 29090569 DOI: 10.1021/acsami.7b14084] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The usage of ZnO as active layers to fabricate hybrid heterojunction light-emitting diodes is expected to be an effective approach for ultraviolet light sources. Individual ZnO microwires with controlled gallium (Ga) incorporation (ZnO/Ga MWs) have been fabricated via a chemical vapor deposition method. It is found that with the increasing Ga-incorporated concentration, the near-band-edge (NBE) photoluminescence of the ZnO MWs blue-shifted gradually from 390 to 370 nm. Heterojunction diodes comprising single ZnO/Ga MWs and p-GaN have been fabricated. With increasing injection currents, the interfacial emissions can be suppressed effectively and the typical NBE emission dominates the electroluminescence (EL). In particular, with increasing Ga-doping concentration, the dominant EL emission wavelengths of the ZnO/Ga MW-based heterojunction diodes blue-shifted from 384 to 372 nm, and the blue shift can be ascribed to the Burstein-Moss effect induced by the Ga incorporation. The present work demonstrates the feasibility of optical band gap engineering of ZnO MWs and the potential application for wavelength-tuning ultraviolet light sources.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
- University of the Chinese Academy of Sciences , Beijing 100049, China
| | - Mingming Jiang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
| | - Gaohang He
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
- University of the Chinese Academy of Sciences , Beijing 100049, China
| | - Shunfang Li
- School of Physics and Engineering, Zhengzhou University , Zhengzhou 450001, China
| | - Zhenzhong Zhang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
| | - Binghui Li
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
| | - Haifeng Zhao
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
| | - Chongxin Shan
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
- School of Physics and Engineering, Zhengzhou University , Zhengzhou 450001, China
| | - Dezhen Shen
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , No. 3888 Dongnanhu Road, Changchun 130033, China
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