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Lv W, Wang L, Lu Y, Wang D, Wang H, Hao Y, Zhang Y, Sun Z, Tang Y. A Study on the Field Emission Characteristics of High-Quality Wrinkled Multilayer Graphene Cathodes. Nanomaterials (Basel) 2024; 14:613. [PMID: 38607147 PMCID: PMC11013809 DOI: 10.3390/nano14070613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/23/2024] [Accepted: 03/24/2024] [Indexed: 04/13/2024]
Abstract
Field emission (FE) necessitates cathode materials with low work function and high thermal and electrical conductivity and stability. To meet these requirements, we developed FE cathodes based on high-quality wrinkled multilayer graphene (MLG) prepared using the bubble-assisted chemical vapor deposition (B-CVD) method and investigated their emission characteristics. The result showed that MLG cathodes prepared using the spin-coating method exhibited a high field emission current density (~7.9 mA/cm2), indicating the excellent intrinsic emission performance of the MLG. However, the weak adhesion between the MLG and the substrate led to the poor stability of the cathode. Screen printing was employed to prepare the cathode to improve stability, and the influence of a silver buffer layer was explored on the cathode's performance. The results demonstrated that these cathodes exhibited better emission stability, and the silver buffer layer further enhanced the comprehensive field emission performance. The optimized cathode possesses low turn-on field strength (~1.5 V/μm), low threshold field strength (~2.65 V/μm), high current density (~10.5 mA/cm2), and good emission uniformity. Moreover, the cathode also exhibits excellent emission stability, with a current fluctuation of only 6.28% during a 4-h test at 1530 V.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Yongliang Tang
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China; (W.L.); (L.W.); (Y.L.); (D.W.); (H.W.); (Y.H.); (Y.Z.); (Z.S.)
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2
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Pradhan BK, Tyagi P, Pal S, Mauraya AK, Roopa, Aggarwal V, Pal P, Kushvaha SS, Muthusamy SK. Role of Surface Chemistry of Ta Metal Foil on the Growth of GaN Nanorods by Laser Molecular Beam Epitaxy and Their Field Emission Characteristics. ACS Appl Mater Interfaces 2024. [PMID: 38427781 DOI: 10.1021/acsami.3c16892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
This study investigates the influence of surface nitridation of Ta metal foil substrates on the growth of GaN nanorods using the laser molecular beam epitaxy (LMBE) technique and the field emission characteristics of the grown GaN nanorod ensemble. Surface morphology examinations underscore the pivotal role of Ta foil nitridation in shaping the dimensions and densities of GaN nanorods. Bare Ta foil fosters the formation of high-density, vertically self-aligned GaN nanorods at a growth temperature of 700 °C. Furthermore, the density of these nanorods is directly related to the duration of Ta foil nitridation, with increased duration leading to a reduced nanorod density. X-ray Photoelectron Spectroscopy (XPS) studies reveal that the transition of the Ta foil surface from tantalum oxide to tantalum nitride during nitridation emerges as a crucial factor influencing GaN nanorod growth. Photoluminescence (PL) spectroscopy at ambient temperature reveals a strong near-band-edge (NBE) emission peak with negligible defect-related peaks, displaying the high optical quality of the GaN nanorods. The highly dense vertically aligned GaN nanorod ensemble growth without Ta prenitridation exhibits the most favorable field emission performance, featuring a turn-on field of 2.1 V/μm, a field enhancement factor of 2480, and a stable long-term operation at the emission current density of 2.26 mA/cm2. This study advances the understanding of the role of the surface chemistry of metal foil in determining GaN nanorod growth and opens up exciting possibilities for tailoring advanced optoelectronic devices for specific application requirements.
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Affiliation(s)
- Bipul Kumar Pradhan
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Prashant Tyagi
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Samanta Pal
- CSIR─Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Amit Kumar Mauraya
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Roopa
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vishnu Aggarwal
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Prabir Pal
- CSIR─Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sunil Singh Kushvaha
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Senthil Kumar Muthusamy
- CSIR─National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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3
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Zhang Y, Cheng P, Wang D, Wang H, Tang Y, Wang W, Li Y, Sun Z, Lv W, Liu Q. Evaluating the Field Emission Properties of N-Type Black Silicon Cold Cathodes Based on a Three-Dimensional Model. ACS Appl Mater Interfaces 2024; 16:2932-2939. [PMID: 38179712 DOI: 10.1021/acsami.3c15402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Black silicon (BS), a nanostructured silicon surface containing highly roughened surface morphology, has recently emerged as a promising candidate for field emission (FE) cathodes in novel electron sources due to its huge number of sharp tips with ease of large-scale fabrication and controllable geometrical shapes. However, evaluating the FE performance of BS-based nanostructures with high accuracy is still a challenge due to the increasing complexity in the surface morphology. Here, we demonstrate a 3D modeling methodology to fully characterize highly disordered BS-based field emitters randomly distributed on a roughened nonflat surface. We fabricated BS cathode samples with different morphological features to demonstrate the validity of this method. We utilize parametrized scanning electron microscopy images that provide high-precision morphology details, successfully describing the electric field distribution in field emitters and linking the theoretical analysis with the measured FE property of the complex nanostructures with high precision. The 3D model developed here reveals a relationship between the field emission performance and the density of the cones, successfully reproducing the classical relationship between current density J and electric field E (J-E curve). The proposed modeling approach is expected to offer a powerful tool to accurately describe the field emission properties of large-scale, disordered nano cold cathodes, thus serving as a guide for the design and application of BS as a field electron emission material.
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Affiliation(s)
- Yuanpeng Zhang
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
| | - Pengfei Cheng
- Institute for Micro and Nanotechnologies MacroNano(R) and Institute for Materials Science and Engineering, Chair of Materials for Electrical Engineering and Electronics, Technische Universität Ilmenau, 98693 Ilmenau, Germany
| | - Dong Wang
- Institute for Micro and Nanotechnologies MacroNano(R) and Institute for Materials Science and Engineering, Chair of Materials for Electrical Engineering and Electronics, Technische Universität Ilmenau, 98693 Ilmenau, Germany
| | - Hui Wang
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
| | - Yongliang Tang
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
| | - Wei Wang
- College of Physics, Sichuan University, Chengdu 610065, China
| | - Yuhang Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zeqi Sun
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
| | - Wenmei Lv
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
| | - Qingxiang Liu
- School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
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4
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Schels A, Herdl F, Hausladen M, Wohlfartsstätter D, Edler S, Bachmann M, Pahlke A, Schreiner R, Hansch W. Quantitative Field Emission Imaging for Studying the Doping-Dependent Emission Behavior of Silicon Field Emitter Arrays. Micromachines (Basel) 2023; 14:2008. [PMID: 38004864 PMCID: PMC10673020 DOI: 10.3390/mi14112008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/26/2023]
Abstract
Field emitter arrays (FEAs) are a promising component for novel vacuum micro- and nanoelectronic devices, such as microwave power amplifiers or fast-switching X-ray sources. However, the interrelated mechanisms responsible for FEA degradation and failure are not fully understood. Therefore, we present a measurement method for quantitative observation of individual emission sites during integral operation using a low-cost, commercially available CMOS imaging sensor. The emission and degradation behavior of three differently doped FEAs is investigated in current-regulated operation. The measurements reveal that the limited current of the p-doped emitters leads to an activation of up to 55% of the individual tips in the array, while the activation of the n-type FEA stopped at around 30%. This enhanced activation results in a more continuous and uniform current distribution for the p-type FEA. An analysis of the individual emitter characteristics before and after a constant current measurement provides novel perspectives on degradation behavior. A burn-in process that trims the emitting tips to an integral current-specific ideal field enhancement factor is observed. In this process, blunt tips are sharpened while sharp tips are dulled, resulting in homogenization within the FEA. The methodology is described in detail, making it easily adaptable for other groups to apply in the further development of promising FEAs.
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Affiliation(s)
- Andreas Schels
- Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich, 85577 Neubiberg, Germany; (F.H.)
| | - Florian Herdl
- Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich, 85577 Neubiberg, Germany; (F.H.)
| | - Matthias Hausladen
- Faculty of Applied Natural and Cultural Sciences, Ostbayerische Technische Hochschule Regensburg, 93053 Regensburg, Germany; (M.H.)
| | | | | | | | | | - Rupert Schreiner
- Faculty of Applied Natural and Cultural Sciences, Ostbayerische Technische Hochschule Regensburg, 93053 Regensburg, Germany; (M.H.)
| | - Walter Hansch
- Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich, 85577 Neubiberg, Germany; (F.H.)
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5
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Chen Y, Chen J, Li Z. Cold Cathodes with Two-Dimensional van der Waals Materials. Nanomaterials (Basel) 2023; 13:2437. [PMID: 37686945 PMCID: PMC10490007 DOI: 10.3390/nano13172437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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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) 2023; 16:5781. [PMID: 37687474 PMCID: PMC10488438 DOI: 10.3390/ma16175781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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von Windheim T, Gilchrist KH, Parker CB, Hall S, Carlson JB, Stokes D, Baldasaro NG, Hess CT, Scheick L, Rax B, Stoner B, Glass JT, Amsden JJ. Proof-of-Concept Vacuum Microelectronic NOR Gate Fabricated Using Microelectromechanical Systems and Carbon Nanotube Field Emitters. Micromachines (Basel) 2023; 14:mi14050973. [PMID: 37241597 DOI: 10.3390/mi14050973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023]
Abstract
This paper demonstrates a fully integrated vacuum microelectronic NOR logic gate fabricated using microfabricated polysilicon panels oriented perpendicular to the device substrate with integrated carbon nanotube (CNT) field emission cathodes. The vacuum microelectronic NOR logic gate consists of two parallel vacuum tetrodes fabricated using the polysilicon Multi-User MEMS Processes (polyMUMPs). Each tetrode of the vacuum microelectronic NOR gate demonstrated transistor-like performance but with a low transconductance of 7.6 × 10-9 S as current saturation was not achieved due to a coupling effect between the anode voltage and cathode current. With both tetrodes working in parallel, the NOR logic capabilities were demonstrated. However, the device exhibited asymmetric performance due to differences in the CNT emitter performance in each tetrode. Because vacuum microelectronic devices are attractive for use in high radiation environments, to test the radiation survivability of this device platform, we demonstrated the function of a simplified diode device structure during exposure to gamma radiation at a rate of 45.6 rad(Si)/second. These devices represent a proof-of-concept for a platform that can be used to build intricate vacuum microelectronic logic devices for use in high-radiation environments.
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Affiliation(s)
- Tasso von Windheim
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | | | - Charles B Parker
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Stephen Hall
- Micross Advanced Interconnect Technology, Research Triangle Park, NC 27709, USA
| | | | - David Stokes
- RTI International, Research Triangle Park, NC 27709, USA
| | | | - Charles T Hess
- Department of Physics, University of Maine, Orono, ME 04469, USA
| | - Leif Scheick
- Jet Propulsion Laboratory, California Institute of Technology, La Canada Flintridge, CA 91011, USA
| | - Bernard Rax
- Jet Propulsion Laboratory, California Institute of Technology, La Canada Flintridge, CA 91011, USA
| | - Brian Stoner
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Jeffrey T Glass
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Jason J Amsden
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
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Wang A, Zhao J, Chen K, Li Z, Li C, Dai Q. Ultra Coherent Single Electron Emission of Carbon Nanotubes. Adv Mater 2023:e2300185. [PMID: 37089030 DOI: 10.1002/adma.202300185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/05/2023] [Indexed: 05/03/2023]
Abstract
The single electron emitter, based on single quantized energy level, can potentially achieve ultimate temporal and spatial coherence with large emission current, which is desirable for the atomic resolution electron probe. This was first developed by constructing a nano-object on a metal tip to form a quantized double barrier structure. However, the single electron emission current can only achieve picoampere level due to the low electron tunneling rate of the heterojunction with large barrier width, which limits their practical applications. In this study, we demonstrated carbon nanotubes (CNTs) can serve as a single electron emitter with current up to 1.5 nA. The double barrier structure formed on the CNT tip enables a high tunneling rate (∼1012 s-1 ) due to the smaller barrier width. The emitter also shows high temporal coherence (energy dispersion ∼10 meV) and spatial coherence (effective source radius ∼0.85 nm). This work represents a high coherent electron source to simplify the electron optics system of atomic resolution electron microscopy and sub-10 nm electron beam lithography. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Aiwei Wang
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jiuzhou Zhao
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ke Chen
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhenjun Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Chi Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qing Dai
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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9
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Neo Y, Hashimoto G, Koike R, Ohhara T, Matsumoto T. Solid-State Far-Ultraviolet C Light Sources for the Disinfection of Pathogenic Microorganisms Using Graphene Nanostructure Field Emitters. Glob Chall 2023; 7:2200236. [PMID: 37020617 PMCID: PMC10069303 DOI: 10.1002/gch2.202200236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/07/2023] [Indexed: 06/19/2023]
Abstract
The ongoing global outbreak of coronavirus disease has necessitated the use of ultraviolet (UV) disinfection techniques to reduce viral transmission in public places. The previously used UV wavelength is harmful to the human body, the wavelength range from 200 to 235 nm, often referred to as far-UVC light, has attracted attention as a novel disinfection wavelength range that can be used in a safe manner. However, the currently used light sources have practical problems, such as an expensive cost, a low efficiency, and short lifetimes. Therefore, environmentally friendly solid-state light sources with a lower cost, higher efficiency, and longer lifetimes are demanded. Here, an efficient mercury-free far-UVC solid-state light source is presented. This light source demonstrates intense 230 nm emission with a narrow spectral width of 30 nm and a long lifetime of more than 1000 h. These characteristics can be achieved by graphene nanostructure field emitters and wide-bandgap magnesium aluminate phosphors. By using this light source, the efficient disinfection of Escherichia coli is demonstrated. The light sources presented here facilitate future technologies for preventing the spread of infectious diseases in a safe and convenient manner.
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Affiliation(s)
- Yoichiro Neo
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Gai Hashimoto
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Rei Koike
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Takashi Ohhara
- Neutron Science SectionJ‐PARC CenterJapan Atomic Energy AgencyIbaraki319‐1195Japan
| | - Takahiro Matsumoto
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
- Graduate School of Medical SciencesNagoya City UniversityNagoya467‐8601Japan
- Graduate School of Design and ArchitectureNagoya City UniversityNagoya464‐0083Japan
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10
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Yu Y, Han D, Wei H, Tang Z, Luo L, Hong T, Shen Y, Zheng H, Wang Y, Wang R, Zhu H, Deng S. Aluminum Nitride Ultraviolet Light-Emitting Device Excited via Carbon Nanotube Field-Emission Electron Beam. Nanomaterials (Basel) 2023; 13:1067. [PMID: 36985961 PMCID: PMC10053685 DOI: 10.3390/nano13061067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
With the progress of wide bandgap semiconductors, compact solid-state light-emitting devices for the ultraviolet wavelength region are of considerable technological interest as alternatives to conventional ultraviolet lamps in recent years. Here, the potential of aluminum nitride (AlN) as an ultraviolet luminescent material was studied. An ultraviolet light-emitting device, equipped with a carbon nanotube (CNT) array as the field-emission excitation source and AlN thin film as cathodoluminescent material, was fabricated. In operation, square high-voltage pulses with a 100 Hz repetition frequency and a 10% duty ratio were applied to the anode. The output spectra reveal a dominant ultraviolet emission at 330 nm with a short-wavelength shoulder at 285 nm, which increases with the anode driving voltage. This work has explored the potential of AlN thin film as a cathodoluminescent material and provides a platform for investigating other ultrawide bandgap (UWBG) semiconductors. Furthermore, while using AlN thin film and a carbon nanotube array as electrodes, this ultraviolet cathodoluminescent device can be more compact and versatile than conventional lamps. It is anticipated to be useful in a variety of applications such as photochemistry, biotechnology and optoelectronics devices.
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Affiliation(s)
- Yangcheng Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Dong Han
- 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
| | - Haiyuan Wei
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Ziying Tang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Lei Luo
- 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
| | - Tianzeng Hong
- 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
| | - Yan Shen
- 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
| | - Huying Zheng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Yaqi Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Runchen Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Hai Zhu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Shaozhi Deng
- 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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11
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Liu X, Qian W, Chen Y, Dong M, Yu T, Huang W, Dong C. Construction of CNT-MgO-Ag-BaO Nanocomposite with Enhanced Field Emission and Hydrogen Sensing Performances. Nanomaterials (Basel) 2023; 13:885. [PMID: 36903763 PMCID: PMC10005578 DOI: 10.3390/nano13050885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
CNTs and CNT-MgO, CNT-MgO-Ag, and CNT-MgO-Ag-BaO nanocomposites were grown on alloy substrates using an electrophoretic deposition method and their field emission (FE) and hydrogen sensing performances were investigated. The obtained samples were characterized by SEM, TEM, XRD, Raman, and XPS characterizations. The CNT-MgO-Ag-BaO nanocomposites showed the best FE performance with turn-on and threshold fields of 3.32 and 5.92 V.μm-1, respectively. The enhanced FE performances are mainly attributed to the reductions of the work function, and the enhancement of the thermal conductivity and emission sites. The current fluctuation of CNT-MgO-Ag-BaO nanocomposites was only 2.4% after a 12 h test at the pressure of 6.0 × 10-6 Pa. In addition, for the hydrogen sensing performances, the CNT-MgO-Ag-BaO sample showed the best increase in amplitude of the emission current among all the samples, with the mean IN increases of 67%, 120%, and 164% for 1, 3, and 5 min emissions, respectively, under the initial emission currents of about 1.0 μA.
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Affiliation(s)
| | - Weijin Qian
- Correspondence: (W.Q.); (C.D.); Tel.: +86-577-86689067 (C.D.)
| | | | | | | | | | - Changkun Dong
- Correspondence: (W.Q.); (C.D.); Tel.: +86-577-86689067 (C.D.)
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12
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Xu J, Lin C, Li Y, Zhao X, Shi Y, Zhang X. Structure Optimization of Planar Nanoscale Vacuum Channel Transistor. Micromachines (Basel) 2023; 14:488. [PMID: 36838188 PMCID: PMC9962290 DOI: 10.3390/mi14020488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/12/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Due to its unique structure, discoveries in nanoscale vacuum channel transistors (NVCTs) have demonstrated novel vacuum nanoelectronics. In this paper, the structural parameters of planar-type NVCTs were simulated, which illustrated the influence of emitter tip morphology on emission performance. Based on simulations, we successfully fabricated back-gate and side-gate NVCTs, respectively. Furthermore, the electric properties of NVCTs were investigated, showing the potential to realize the high integration of vacuum transistors.
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Affiliation(s)
- Ji Xu
- School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Congyuan Lin
- School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yu Li
- School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Xueliang Zhao
- School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yongjiao Shi
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
| | - Xiaobing Zhang
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
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13
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Zhang W, Chao P, Chen D, Yang Z, Dong L. A Core-Shell MWCNT-Pt Nanowire Electron Source with Anomalously Long-Term Stable Field Emission. Nanomaterials (Basel) 2023; 13:532. [PMID: 36770493 PMCID: PMC9921140 DOI: 10.3390/nano13030532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/25/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
A hybrid core-shell structured nanowire is proposed for a long-term stable electron source based on an isolated platinum/multi-walled carbon nanotube (Pt/MWCNT). This hybrid nanowire is prepared by growing a Pt shell on a metallic MWCNT through a field-emission-induced deposition (FEID) method. An in situ field emission (FE) platform was constructed inside a scanning electron microscope (SEM) equipped with two nanorobotic manipulators (NRMs) for the preparation and testing of the hybrid nanowire. An in situ fatigue test was conducted with high current intensity (500 nA) to show the influence of the Pt shell. Compared with the pristine bare MWCNT, our hybrid-nanowire-based electron source has a lifetime of hundreds of times longer and can work continuously for up to 48 h under relatively high pressure (3.6×10-3 Pa) without having an apparent change in its structure or emission currents, demonstrating good stability and tolerance to poor working conditions. The anomalous long-term stability is attributed mainly to the shielding of oxygen by Pt from the carbon shells and less heating due to the work function lowering by Pt.
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Affiliation(s)
- Wenqi Zhang
- Jiangsu Provincial Key Laboratory of Advanced Robotics, School of Mechanical and Electric Engineering, Soochow University; Suzhou 215000, China
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Peidong Chao
- Jiangsu Provincial Key Laboratory of Advanced Robotics, School of Mechanical and Electric Engineering, Soochow University; Suzhou 215000, China
| | - Donglei Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Zhan Yang
- Jiangsu Provincial Key Laboratory of Advanced Robotics, School of Mechanical and Electric Engineering, Soochow University; Suzhou 215000, China
| | - Lixin Dong
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China
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14
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Zhang Y, Liu X, Zhao L, Li Y, Li Z. Simulation and Optimization of CNTs Cold Cathode Emission Grid Structure. Nanomaterials (Basel) 2022; 13:50. [PMID: 36615960 PMCID: PMC9824370 DOI: 10.3390/nano13010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Carbon nanotubes (CNTs) show significant advantages in the development of cold cathode X-ray tubes due to their excellent field emission performance; however, there are still some problems, such as short lifetime and the low emission current of large-area CNTs. In this paper, a front-grid carbon nanotube array model was established, and the electric field intensity near the tip of the CNTs' electric field enhancement factor was analytically calculated. A simulation model of a CNT three-dimensional field emission electron gun was established by using computer simulation technology (CST). The effects of grid wire diameter, grid aperture shape, and the distribution of grid projection on the cathode surface on the cathode current, anode current, and electron transmission efficiency were analyzed. The aperture ratio was used to evaluate the grid performance, and the simulation results show that the ideal aperture ratio should be between 65% and 85%. A grid structure combining a coarse grid and a fine grid was designed, which can make the electric field intensity around the grid evenly distributed, and effectively increased the cathode emission current by 24.2% compared with the structure without the fine grid. The effect of grid aperture ratio on the electron transmission efficiency was tested. The simulation results and optimized structure can provide a reference for the grid design of cold cathode emission X-ray tubes.
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Affiliation(s)
- Yang Zhang
- School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China
- Key Laboratory of Micro-Inertial Instruments and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, China
| | - Xinchuan Liu
- CAS Key Laboratory of Nanophotonic Materials and Devices (Preparatory), National Center for Nanoscience and Technology, Beijing 100190, China
| | - Liye Zhao
- School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China
- Key Laboratory of Micro-Inertial Instruments and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, China
| | - Yuanxun Li
- School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China
- Key Laboratory of Micro-Inertial Instruments and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, China
- CAS Key Laboratory of Nanophotonic Materials and Devices (Preparatory), National Center for Nanoscience and Technology, Beijing 100190, China
| | - Zhenjun Li
- CAS Key Laboratory of Nanophotonic Materials and Devices (Preparatory), National Center for Nanoscience and Technology, Beijing 100190, China
- GBA Research Innovation Institute for Nanotechnology, Guangzhou 510700, China
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15
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Adhikari BC, Ketan B, Kim JS, Yoo ST, Choi EH, Park KC. Beam Trajectory Analysis of Vertically Aligned Carbon Nanotube Emitters with a Microchannel Plate. Nanomaterials (Basel) 2022; 12:4313. [PMID: 36500936 PMCID: PMC9738669 DOI: 10.3390/nano12234313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Vertically aligned carbon nanotubes (CNTs) are essential to studying high current density, low dispersion, and high brightness. Vertically aligned 14 × 14 CNT emitters are fabricated as an island by sputter coating, photolithography, and the plasma-enhanced chemical vapor deposition process. Scanning electron microscopy is used to analyze the morphology structures with an average height of 40 µm. The field emission microscopy image is captured on the microchannel plate (MCP). The role of the microchannel plate is to determine how the high-density electron beam spot is measured under the variation of voltage and exposure time. The MCP enhances the field emission current near the threshold voltage and protects the CNT from irreversible damage during the vacuum arc. The high-density electron beam spot is measured with an FWHM of 2.71 mm under the variation of the applied voltage and the exposure time, respectively, which corresponds to the real beam spot. This configuration produces the beam trajectory with low dispersion under the proper field emission, which could be applicable to high-resolution multi-beam electron microscopy and high-resolution X-ray imaging technology.
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Affiliation(s)
- Bishwa Chandra Adhikari
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Bhotkar Ketan
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Ju Sung Kim
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center (PBRC), Kwangwoon University, Seoul 01897, Republic of Korea
| | - Sung Tae Yoo
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Eun Ha Choi
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center (PBRC), Kwangwoon University, Seoul 01897, Republic of Korea
| | - Kyu Chang Park
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
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16
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Yoo ST, Park KC. Extreme Ultraviolet Lighting Using Carbon Nanotube-Based Cold Cathode Electron Beam. Nanomaterials (Basel) 2022; 12:4134. [PMID: 36500759 PMCID: PMC9739857 DOI: 10.3390/nano12234134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Laser-based plasma studies that apply photons to extreme ultraviolet (EUV) generation are actively being conducted, and studies by direct electron irradiation on Sn for EUV lighting have rarely been attempted. Here, we demonstrate a novel method of EUV generation by irradiating Sn with electrons emitted from a carbon nanotube (CNT)-based cold cathode electron beam (C-beam). Unlike a single laser source, electrons emitted from about 12,700 CNT emitters irradiated the Sn surface to generate EUV and control its intensity. EUV light generated by direct irradiation of electrons was verified using a photodiode equipped with a 150 nm thick Zr filter and patterning of polymethyl methacrylate (PMMA) photoresist. EUV generated with an input power of 6 W is sufficient to react the PMMA with exposure of 30 s. EUV intensity changes according to the anode voltage, current, and electron incident angle. The area reaching the Sn and penetration depth of electrons are easily adjusted. This method could be the cornerstone for advanced lithography for semiconductor fabrication and high-resolution photonics.
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17
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Nirantar S, Patil B, Tripathi DC, Sethu N, Narayanan RV, Tian J, Bhaskaran M, Walia S, Sriram S. Metal-Air Field Emission Devices - Nano Electrode Geometries Comparison of Performance and Stability. Small 2022; 18:e2203234. [PMID: 36094789 DOI: 10.1002/smll.202203234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Air-channel devices have a special advantage due to the promise of vacuum-like ballistic transport in air, radiation insensitivity, and nanoscale size. Here, achieving high current at low voltage along with considerable mechanical stability is a primary issue. The comparative analysis of four planar and metallic electrode-pair geometries at 10 nm channel length is presented. The impact of nano-electrode-pair geometries on overall device performance is investigated. Air-channel devices are operated at the ultra-low voltage of 5 mV to demonstrate the device dynamics of air-channel devices at low power. Investigations focus on the direct tunneling (DT) mechanism which is dominant in the low-voltage regime. Comparative analysis of different electrode-pair geometries reveals two orders of magnitude increment in the current just by modulating the electrode-pair structure. Theoretical analysis suggests that the emission current is directly related to the active junction area within the metal-air-metal interface at the direct tunneling regime. The geometry-dependent mechanical stability of different electrode pairs is compared by imaging biasing triggered nanoscale structural changes and pulsed biasing stress analysis. The results and claims are confirmed and consolidated with the statistical analysis. Experimental investigations provide strong directions for high-performance and stable devices. In-depth theoretical discussions will enable the accurate modeling of emerging low-power, high-speed, radiation-hardened nanoscale vacuum electronics.
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Affiliation(s)
- Shruti Nirantar
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Basanagounda Patil
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Durgesh C Tripathi
- Faculty of Electrical Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Nilamani Sethu
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Ramakrishnan V Narayanan
- Department of Micro and Nanoelectronics, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Jie Tian
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Sumeet Walia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Victoria, 3001, Australia
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
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18
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Hong T, Zhan R, Zhang Y, Deng S. High Crystallinity Vertical Few-Layer Graphene Grown Using Template Method Assisted ICPCVD Approach. Nanomaterials (Basel) 2022; 12:3746. [PMID: 36364521 PMCID: PMC9658688 DOI: 10.3390/nano12213746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/15/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Controllable synthesis of high crystallinity, low defects vertical few-layer graphene (VFLG) is significant for its application in electron emission, sensor or energy storage, etc. In this paper, a template method was introduced to grow high crystallinity VFLG (HCVFLG). A copper mask acted as a template which has two effects in the high-density plasma enhanced deposition which are protecting VFLG from ion etching and creating a molecular gas flow to assist efficient growth. Raman and TEM results confirmed the improved crystallinity of VFLG with the assistance of a copper mask. As a field emitter, the HCVFLG has a large field emission current and a low turn-on field. The maximum field emission current of a single HCVFLG sheet reaches 93 μA which is two orders of magnitude higher than VFLG grown without a mask. The maximum current density of HCVFLG film reached 67.15 mA/cm2 and is 2.6 times of VFLG grown without a mask. The vacuum breakdown mechanism of HCVFLG was contacted interface damage resulting in VFLG detaching from the substrate. This work provides a practical strategy for high-quality VFLG controllable synthesis and provides a simple method to realize the pattern growth of VFLG.
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19
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de Assis TA, Dall'Agnol FF, Forbes RG. Field emitter electrostatics: a review with special emphasis on modern high-precision finite-element modelling. J Phys Condens Matter 2022; 34:493001. [PMID: 36103867 DOI: 10.1088/1361-648x/ac920a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
This review of the quantitative electrostatics of field emitters, covering analytical, numerical and 'fitted formula' approaches, is thought the first of its kind in the 100 years of the subject. The review relates chiefly to situations where emitters operate in an electronically ideal manner, and zero-current electrostatics is applicable. Terminology is carefully described and is 'polarity independent', so that the review applies to both field electron and field ion emitters. It also applies more generally to charged, pointed electron-conductors-which exhibit the 'electrostatic lightning-rod effect', but are poorly discussed in general electricity and magnetism literature. Modern electron-conductor electrostatics is an application of the chemical thermodynamics and statistical mechanics of electrons. In related theory, the primary role of classical electrostatic potentials (rather than fields) becomes apparent. Space and time limitations have meant that the review cannot be comprehensive in both detail and scope. Rather, it focuses chiefly on the electrostatics of two common basic emitter forms: the needle-shaped emitters used in traditional projection technologies; and the post-shaped emitters often used in modelling large-area multi-emitter electron sources. In the post-on-plane context, we consider in detail both the electrostatics of the single post and the interaction between two identical posts that occurs as a result of electrostatic depolarization (often called 'screening' or 'shielding'). Core to the review are discussions of the 'minimum domain dimensions' method for implementing effective finite-element-method electrostatic simulations, and of the variant of this that leads to very precise estimates of dimensionless field enhancement factors (error typically less than 0.001% in simple situations where analytical comparisons exist). Brief outline discussions, and some core references, are given for each of many 'related considerations' that are relevant to the electrostatic situations, methods and results described. Many areas of field emitter electrostatics are suggested where further research and/or separate mini-reviews would probably be useful.
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Affiliation(s)
- Thiago A de Assis
- Instituto de Física, Universidade Federal da Bahia, Campus Universitário da Federação, Rua Barão de Jeremoabo s/n, 40170-115 Salvador, BA, Brazil
| | - Fernando F Dall'Agnol
- Department of Exact Sciences and Education (CEE), Universidade Federal de Santa Catarina, Campus Blumenau, Rua João Pessoa, 2514, Velha, Blumenau 89036-004, SC, Brazil
| | - Richard G Forbes
- Advanced Technology Institute & School of Computer Science and Electronic Engineering, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
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20
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Gerasimenko AY, Kuksin AV, Shaman YP, Kitsyuk EP, Fedorova YO, Murashko DT, Shamanaev AA, Eganova EM, Sysa AV, Savelyev MS, Telyshev DV, Pavlov AA, Glukhova OE. Hybrid Carbon Nanotubes-Graphene Nanostructures: Modeling, Formation, Characterization. Nanomaterials (Basel) 2022; 12:nano12162812. [PMID: 36014677 PMCID: PMC9412346 DOI: 10.3390/nano12162812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/12/2022] [Accepted: 08/13/2022] [Indexed: 06/06/2023]
Abstract
A technology for the formation and bonding with a substrate of hybrid carbon nanostructures from single-walled carbon nanotubes (SWCNT) and reduced graphene oxide (rGO) by laser radiation is proposed. Molecular dynamics modeling by the real-time time-dependent density functional tight-binding (TD-DFTB) method made it possible to reveal the mechanism of field emission centers formation in carbon nanostructures layers. Laser radiation stimulates the formation of graphene-nanotube covalent contacts and also induces a dipole moment of hybrid nanostructures, which ensures their orientation along the force lines of the radiation field. The main mechanical and emission characteristics of the formed hybrid nanostructures were determined. By Raman spectroscopy, the effect of laser radiation energy on the defectiveness of all types of layers formed from nanostructures was determined. Laser exposure increased the hardness of all samples more than twice. Maximum hardness was obtained for hybrid nanostructure with a buffer layer (bl) of rGO and the main layer of SWCNT-rGO(bl)-SWCNT and was 54.4 GPa. In addition, the adhesion of rGO to the substrate and electron transport between the substrate and rGO(bl)-SWCNT increased. The rGO(bl)-SWCNT cathode with an area of ~1 mm2 showed a field emission current density of 562 mA/cm2 and stability for 9 h at a current of 1 mA. The developed technology for the formation of hybrid nanostructures can be used both to create high-performance and stable field emission cathodes and in other applications where nanomaterials coating with good adhesion, strength, and electrical conductivity is required.
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Affiliation(s)
- Alexander Yu. Gerasimenko
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
- Institute for Bionic Technologies and Engineering, I.M. Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street 2-4, 119991 Moscow, Russia
| | - Artem V. Kuksin
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
| | - Yury P. Shaman
- Scientific-Manufacturing Complex “Technological Centre”, Shokin Square 1, bld. 7 off. 7237, 124498 Moscow, Russia
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, Leninsky Prospekt 32A, 119991 Moscow, Russia
| | - Evgeny P. Kitsyuk
- Scientific-Manufacturing Complex “Technological Centre”, Shokin Square 1, bld. 7 off. 7237, 124498 Moscow, Russia
| | - Yulia O. Fedorova
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
- Scientific-Manufacturing Complex “Technological Centre”, Shokin Square 1, bld. 7 off. 7237, 124498 Moscow, Russia
| | - Denis T. Murashko
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
| | - Artemiy A. Shamanaev
- Scientific-Manufacturing Complex “Technological Centre”, Shokin Square 1, bld. 7 off. 7237, 124498 Moscow, Russia
| | - Elena M. Eganova
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, Leninsky Prospekt 32A, 119991 Moscow, Russia
| | - Artem V. Sysa
- Scientific-Manufacturing Complex “Technological Centre”, Shokin Square 1, bld. 7 off. 7237, 124498 Moscow, Russia
| | - Mikhail S. Savelyev
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
- Institute for Regenerative Medicine, I.M. Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street 2-4, 119991 Moscow, Russia
| | - Dmitry V. Telyshev
- Institute of Biomedical Systems, National Research University of Electronic Technology MIET, Shokin Square 1, 124498 Moscow, Russia
- Institute for Bionic Technologies and Engineering, I.M. Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street 2-4, 119991 Moscow, Russia
| | - Alexander A. Pavlov
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, Leninsky Prospekt 32A, 119991 Moscow, Russia
| | - Olga E. Glukhova
- Institute for Bionic Technologies and Engineering, I.M. Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street 2-4, 119991 Moscow, Russia
- Department of Physics, Saratov State University, Astrakhanskaya Street 83, 410012 Saratov, Russia
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21
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Xu J, Lin C, Shi Y, Li Y, Zhao X, Zhang X, Zhang J. Optimization of a Field Emission Electron Source Based on Nano-Vacuum Channel Structures. Micromachines (Basel) 2022; 13:1274. [PMID: 36014196 PMCID: PMC9414455 DOI: 10.3390/mi13081274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Recent discoveries in the field of nanoscale vacuum channel (NVC) structures have led to potential on-chip electron sources. However, limited research has reported on the structure or material parameters, and the superiority of a nanoscale vacuum channel in an electron source has not been adequately demonstrated. In this paper, we perform the structural optimization design of an NVC-based electron source. First, the structure parameters of a vertical NVC-based electron source are investigated. Moreover, the symmetrical NVC structure is further demonstrated to improve the emission current and effective electron efficiency. Finally, a symmetrical nano-vacuum channel structure is successfully fabricated based on simulations. The results show that the anode current exceeds 15 nA and that the effective electron efficiency exceeds 20%. Further miniaturizing the NVC structures in high integration can be utilized as an on-chip electron source, thereby, illustrating the potential in applications of electron microscopes, miniature X-ray sources and on-chip traveling wave tubes.
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Affiliation(s)
- Ji Xu
- School of Electronic and Information Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Congyuan Lin
- School of Electronic and Information Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Yongjiao Shi
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
| | - Yu Li
- School of Electronic and Information Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Xueliang Zhao
- School of Electronic and Information Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Xiaobing Zhang
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
| | - Jian Zhang
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
- Wenzhou Key Lab of Micro-nano Optoelectronic Devices, Wenzhou University, Wenzhou 325035, China
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22
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Kleshch VI, Ismagilov RR, Mukhin VV, Orekhov AS, Filatyev AS, Obraztsov AN. Nano-graphite field-emission cathode for space electric propulsion systems. Nanotechnology 2022; 33:415201. [PMID: 35785757 DOI: 10.1088/1361-6528/ac7def] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Improving the thruster efficiency is a crucial challenge for the development of space electric propulsion systems, especially advanced air-breathing thrusters utilizing the surrounding rarefied atmosphere as fuel. A significant reduction in thruster power consumption can be achieved by using field emission (FE) cathodes that do not require heating and have the highest energy efficiency. In this work, we study FE from nano-graphite thin films, consisting of carbon nanostructures with a high aspect ratio, and demonstrate their suitability for use in the space electric propulsion systems. The films shown appropriate FE characteristics in a wide range of gas pressures at high current loads in constant and pulsed operation modes. Based on the obtained experimental results, nano-graphite cathodes were employed for the design of an electron gun with increased reliability and minimized energy losses associated with electron extraction. The possibility of using such a gun in a specific air-breathing satellite operating in low Earth orbits is demonstrated.
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Affiliation(s)
| | | | | | - Anton S Orekhov
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
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23
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Pulagara NV, Lahiri I. Carbon nanotube-tungsten nanowire hierarchical structure for augmented field emission performance. Nanotechnology 2022; 33:305704. [PMID: 35395656 DOI: 10.1088/1361-6528/ac659f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
An increasing number of emitting sites and higher aspect ratios are constantly being added to field emission systems to further improve their properties. Such an ever-growing demand has thrown light on the development of hierarchical field emitters. Tungsten (W) and carbon nanotubes (CNT) have been commonly reported as potential field emitter materials. The present work focused on constructing a hierarchical field emitter structure of CNTs/W nanowires. The structural characterization has been studied using field emission scanning electron microscopy, high-resolution transmission electron microscopy, and x-ray diffraction to confirm the hierarchical structure formation. The carbon nanotube-tungsten nanowire hierarchical structural emitters have demonstrated high current density (31.5 mA cm-2), exceptionally low turn-on field (0.068 Vμm-1), and emission stability for more than 152 h. This excellent performance could be related to the formation of a strong as well as the electrically favourable interface between tungsten nanowires and CNTs.
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Affiliation(s)
- Narasimha Vinod Pulagara
- Nanomaterials and Application Lab., Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee, UK-247667, India
| | - Indranil Lahiri
- Nanomaterials and Application Lab., Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee, UK-247667, India
- Centre of Excellence: Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, UK-247667, India
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24
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Tang H, Liu R, Huang W, Zhu W, Qian W, Dong C. Field Emission of Multi-Walled Carbon Nanotubes from Pt-Assisted Chemical Vapor Deposition. Nanomaterials (Basel) 2022; 12:nano12030575. [PMID: 35159920 PMCID: PMC8838496 DOI: 10.3390/nano12030575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023]
Abstract
Multi-walled carbon nanotubes (MWNTs) were grown directly on a metal substrate with the assistance of Pt using a chemical vapor deposition method. In addition, the growth mechanism of Pt-assisted catalytic CNT was discussed. MWNTs were characterized by SEM, TEM, AFM, Raman, and EDS, and the field emission (FE) properties were investigated, comparing with the direct grown MWNTs. The results showed that CNTs could not been synthesized by Pt particles alone under the experimental condition, but Pt may accelerate the decomposition of the carbon source gas, i.e., assisting MWNT growth with other catalysts. The Pt-assisted MWNTs were longer with larger diameters of around 80 nm and possessed better structural qualities with very few catalyst particles inside. Improved field emission properties were demonstrated for the Pt-assisted MWNTs with lower turn-on fields (for 0.01 mA·cm−2 current density) of 2.0 V·μm−1 and threshold field (for 10 mA·cm−2 current density) of 3.5 V·μm−1, as well as better stability under a long-term test of 80 h (started at 3.0 mA for the Pt-assisted emitter and 3.25 mA for the direct grown emitter). This work demonstrated a promising approach to develop high performance CNT field emitters for device applications.
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25
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Jiang R, Liu J, Yang K, Zhao J, Zeng B. Enhanced Field Emission of Single-Wall Carbon Nanotube Cathode Prepared by Screen Printing with a Silver Paste Buffer Layer. Nanomaterials (Basel) 2022; 12:165. [PMID: 35010115 DOI: 10.3390/nano12010165] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/18/2021] [Accepted: 12/22/2021] [Indexed: 11/17/2022]
Abstract
A high emission current with relatively low operating voltage is critical for field emission cathodes in vacuum electronic devices (VEDs). This paper studied the field emission performance of single-wall carbon nanotube (SWCNT) cold cathodes prepared by screen printing with a silver paste buffer layer. The buffer layer can both enforce the adhesion between the SWCNTs and substrate, and decrease their contact resistance, so as to increase emission current. Compared with paste mixing CNTs and screen printed cathodes, the buffer layer can avoid excessive wrapping of CNTs in the silver slurry and increase effective emission area to reduce the operating voltage. The experimental results show that the turn-on field of the screen-printed SWCNT cathodes is 0.9 V/μm, which is lower than that of electrophoretic SWCNT cathodes at 2.0 V/μm. Meanwhile, the maximum emission current of the screen-printed SWCNT cathodes reaches 5.55 mA at DC mode and reaches 10.4 mA at pulse mode, which is an order magnitude higher than that of electrophoretic SWCNTs emitters. This study also shows the application insight of small or medium-power VEDs.
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26
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Huang L, Wu X, Hijiya R, Teii K. Control of electrostatic self-assembly seeding of diamond nanoparticles on carbon nanowalls. Nanotechnology 2021; 33:105605. [PMID: 34907905 DOI: 10.1088/1361-6528/ac3358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/26/2021] [Indexed: 06/14/2023]
Abstract
Seeding of diamond nanoparticles on vertically-aligned multi-layer graphene, the so-called carbon nanowalls (CNWs), is studied by using deionized water, ethylene glycol, ethanol, and formamide as dispersion mediums. Detonation nanodiamond particles show the smallest mean size and size distribution with a high positive zeta potential when dispersed in ethanol. The contact angle of ethanol on CNWs is almost zero degree, confirming highly wetting behaviour. The diamond nanoparticles dispersed in ethanol are distributed the most uniformly with minimal aggregation on CNWs as opposed to those dispersed in other liquids. The resulting diamond nanoparticle-seeded CNWs, followed by short-term growth in microwave plasma chemical vapor deposition, show a marked decrease in field emission turn-on field down to 1.3 Vμm-1together with a large increase in current density, compared to bare CNWs without diamond seeding. The results provide a way to control the density, size, and uniformity (spacing) of diamond nanoparticles on CNWs and should be applied to fabricate hybrid materials and devices using nanodiamond and nanocarbons.
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Affiliation(s)
- Lei Huang
- Department of Advanced Energy Science and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Xiangqing Wu
- School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Ryota Hijiya
- Department of Advanced Energy Science and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Kungen Teii
- Department of Advanced Energy Science and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
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27
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Haugg S, Hedrich C, Blick RH, Zierold R. Subtractive Low-Temperature Preparation Route for Porous SiO 2 Used for the Catalyst-Assisted Growth of ZnO Field Emitters. Nanomaterials (Basel) 2021; 11:3357. [PMID: 34947706 PMCID: PMC8709353 DOI: 10.3390/nano11123357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/19/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022]
Abstract
The possibility to gradually increase the porosity of thin films facilitates a variety of applications, such as anti-reflective coatings, diffusion membranes, and the herein investigated tailored nanostructuring of a substrate for subsequent self-assembly processes. A low-temperature (<160 °C) preparation route for porous silicon oxide (porSiO2) thin films with porosities of about 60% and effective refractive indices down to 1.20 is tailored for bulk as well as free-standing membranes. Subsequently, both substrate types are successfully employed for the catalyst-assisted growth of nanowire-like zinc oxide (ZnO) field emitters by metal organic chemical vapor deposition. ZnO nanowires can be grown with a large aspect ratio and exhibit a good thermal and chemical stability, which makes them excellent candidates for field emitter arrays. We present a method that allows for the direct synthesis of nanowire-like ZnO field emitters on free-standing membranes using a porSiO2 template. Besides the application of porSiO2 for the catalyst-assisted growth of nanostructures and their use as field emission devices, the herein presented general synthesis route for the preparation of low refractive index films on other than bulk substrates-such as on free-standing, ultra-thin membranes-may pave the way for the employment of porSiO2 in micro-electro-mechanical systems.
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Affiliation(s)
- Stefanie Haugg
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, 22761 Hamburg, Germany; (S.H.); (C.H.); (R.H.B.)
| | - Carina Hedrich
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, 22761 Hamburg, Germany; (S.H.); (C.H.); (R.H.B.)
| | - Robert H. Blick
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, 22761 Hamburg, Germany; (S.H.); (C.H.); (R.H.B.)
- Material Science and Engineering, College of Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Robert Zierold
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, 22761 Hamburg, Germany; (S.H.); (C.H.); (R.H.B.)
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28
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Zhao J, Li Z, Cole MT, Wang A, Guo X, Liu X, Lyu W, Teng H, Qv Y, Liu G, Chen K, Zhou S, Xiao J, Li Y, Li C, Dai Q. Nanocone-Shaped Carbon Nanotubes Field-Emitter Array Fabricated by Laser Ablation. Nanomaterials (Basel) 2021; 11:nano11123244. [PMID: 34947593 PMCID: PMC8707308 DOI: 10.3390/nano11123244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/25/2021] [Accepted: 11/25/2021] [Indexed: 11/21/2022]
Abstract
The nanocone-shaped carbon nanotubes field-emitter array (NCNA) is a near-ideal field-emitter array that combines the advantages of geometry and material. In contrast to previous methods of field-emitter array, laser ablation is a low-cost and clean method that does not require any photolithography or wet chemistry. However, nanocone shapes are hard to achieve through laser ablation due to the micrometer-scale focusing spot. Here, we develop an ultraviolet (UV) laser beam patterning technique that is capable of reliably realizing NCNA with a cone-tip radius of ≈300 nm, utilizing optimized beam focusing and unique carbon nanotube–light interaction properties. The patterned array provided smaller turn-on fields (reduced from 2.6 to 1.6 V/μm) in emitters and supported a higher (increased from 10 to 140 mA/cm2) and more stable emission than their unpatterned counterparts. The present technique may be widely applied in the fabrication of high-performance CNTs field-emitter arrays.
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Affiliation(s)
- Jiuzhou Zhao
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China; (J.Z.); (W.L.)
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
| | - Zhenjun Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- GBA Research Innovation Institute for Nanotechnology, Guangzhou 510700, China
| | - Matthew Thomas Cole
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK;
| | - Aiwei Wang
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangdong Guo
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinchuan Liu
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
| | - Wei Lyu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China; (J.Z.); (W.L.)
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
| | - Hanchao Teng
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunpeng Qv
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanjiang Liu
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
| | - Ke Chen
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shenghan Zhou
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianfeng Xiao
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
| | - Yi Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China; (J.Z.); (W.L.)
- Joint School of National University of Singapore and Tianjin University, Fuzhou International Campus, Tianjin University, Binhai New City, Fuzhou 350207, China
- Correspondence: (Y.L.); (C.L.); (Q.D.)
| | - Chi Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (Y.L.); (C.L.); (Q.D.)
| | - Qing Dai
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (Z.L.); (A.W.); (X.G.); (X.L.); (H.T.); (Y.Q.); (G.L.); (K.C.); (S.Z.); (J.X.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (Y.L.); (C.L.); (Q.D.)
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Xiao J, Zhao J, Liu G, Cole MT, Zhou S, Chen K, Liu X, Li Z, Li C, Dai Q. Stable Field Emission from Vertically Oriented SiC Nanoarrays. Nanomaterials (Basel) 2021; 11:3025. [PMID: 34835790 PMCID: PMC8622368 DOI: 10.3390/nano11113025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022]
Abstract
Silicon carbide (SiC) nanostructure is a type of promising field emitter due to high breakdown field strength, high thermal conductivity, low electron affinity, and high electron mobility. However, the fabrication of the SiC nanotips array is difficult due to its chemical inertness. Here we report a simple, industry-familiar reactive ion etching to fabricate well-aligned, vertically orientated SiC nanoarrays on 4H-SiC wafers. The as-synthesized nanoarrays had tapered base angles >60°, and were vertically oriented with a high packing density >107 mm-2 and high-aspect ratios of approximately 35. As a result of its high geometry uniformity-5% length variation and 10% diameter variation, the field emitter array showed typical turn-on fields of 4.3 V μm-1 and a high field-enhancement factor of ~1260. The 8 h current emission stability displayed a mean current fluctuation of 1.9 ± 1%, revealing excellent current emission stability. The as-synthesized emitters demonstrate competitive emission performance that highlights their potential in a variety of vacuum electronics applications. This study provides a new route to realizing scalable field electron emitter production.
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Affiliation(s)
- Jianfeng Xiao
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, China; (J.X.); (Q.D.)
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
| | - Jiuzhou Zhao
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
| | - Guanjiang Liu
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
| | - Mattew Thomas Cole
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK;
| | - Shenghan Zhou
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ke Chen
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinchuan Liu
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
| | - Zhenjun Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- GBA Research Innovation Institute for Nanotechnology, Guangzhou 510700, China
| | - Chi Li
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Dai
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, China; (J.X.); (Q.D.)
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China; (J.Z.); (G.L.); (S.Z.); (K.C.); (X.L.)
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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Kazanowska BA, Sapkota KR, Lu P, Talin AA, Bussmann E, Ohta T, Gunning BP, Jones KS, Wang GT. Fabrication and field emission properties of vertical, tapered GaN nanowires etched via phosphoric acid. Nanotechnology 2021; 33:035301. [PMID: 34555820 DOI: 10.1088/1361-6528/ac2981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
The controlled fabrication of vertical, tapered, and high-aspect ratio GaN nanowires via a two-step top-down process consisting of an inductively coupled plasma reactive ion etch followed by a hot, 85% H3PO4crystallographic wet etch is explored. The vertical nanowires are oriented in the[0001]direction and are bound by sidewalls comprising of{336¯2}semipolar planes which are at a 12° angle from the [0001] axis. High temperature H3PO4etching between 60 °C and 95 °C result in smooth semipolar faceting with no visible micro-faceting, whereas a 50 °C etch reveals a micro-faceted etch evolution. High-angle annular dark-field scanning transmission electron microscopy imaging confirms nanowire tip dimensions down to 8-12 nanometers. The activation energy associated with the etch process is 0.90 ± 0.09 eV, which is consistent with a reaction-rate limited dissolution process. The exposure of the{336¯2}type planes is consistent with etching barrier index calculations. The field emission properties of the nanowires were investigated via a nanoprobe in a scanning electron microscope as well as by a vacuum field emission electron microscope. The measurements show a gap size dependent turn-on voltage, with a maximum current of 33 nA and turn-on field of 1.92 V nm-1for a 50 nm gap, and uniform emission across the array.
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Affiliation(s)
- Barbara A Kazanowska
- University of Florida, Department of Materials Science and Engineering, Gainesville, FL 32611, United States of America
| | - Keshab R Sapkota
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Ping Lu
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - A Alec Talin
- Sandia National Laboratories, Livermore, CA 94550, United States of America
| | - Ezra Bussmann
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Taisuke Ohta
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Brendan P Gunning
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Kevin S Jones
- University of Florida, Department of Materials Science and Engineering, Gainesville, FL 32611, United States of America
| | - George T Wang
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
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Qin M, Han X, Ding D, Niu R, Qu Z, Wang Z, Liao ZM, Gan Z, Huang Y, Han C, Lu J, Ye J. Light Controllable Electronic Phase Transition in Ionic Liquid Gated Monolayer Transition Metal Dichalcogenides. Nano Lett 2021; 21:6800-6806. [PMID: 34369798 DOI: 10.1021/acs.nanolett.1c01467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ionic liquid gating has proved to be effective in inducing emergent quantum phenomena such as superconductivity, ferromagnetism, and topological states. The electrostatic doping at two-dimensional interfaces relies on ionic motion, which thus is operated at sufficiently high temperature. Here, we report the in situ tuning of quantum phases by shining light on an ionic liquid-gated interface at cryogenic temperatures. The light illumination enables flexible switching of the quantum transition in monolayer WS2 from an insulator to a superconductor. In contrast to the prevailing picture of photoinduced carriers, we find that in the presence of a strong interfacial electric field conducting electrons could escape from the surface confinement by absorbing photons, mimicking the field emission. Such an optical tuning tool in conjunction with ionic liquid gating greatly facilitates continuous modulation of carrier densities and hence electronic phases, which would help to unveil novel quantum phenomena and device functionality in various materials.
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Affiliation(s)
- Maosen Qin
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiangyan Han
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Dongdong Ding
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Ruirui Niu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhuangzhuang Qu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhiyu Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Yangtze Delta Institute of Optoelectronics, Peking University, Nantong, Jiangsu 226010 China
| | - Zizhao Gan
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China
| | - Chunrui Han
- Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jianming Lu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Jianting Ye
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9746AG, The Netherlands
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Chen Y, Deng S, Xu N, Chen J. Recent Progress on ZnO Nanowires Cold Cathode and Its Applications. Nanomaterials (Basel) 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Lee HR, Kim DW, Rodiansyah A, Cho B, Lim J, Park KC. Investigation of the Effect of Structural Properties of a Vertically Standing CNT Cold Cathode on Electron Beam Brightness and Resolution of Secondary Electron Images. Nanomaterials (Basel) 2021; 11:1918. [PMID: 34443749 PMCID: PMC8399544 DOI: 10.3390/nano11081918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 11/16/2022]
Abstract
Carbon nanotube (CNT)-based cold cathodes are promising sources of field emission electrons for advanced electron devices, particularly for ultra-high-resolution imaging systems, due to their high brightness and low energy spread. While the electron field emission properties of single-tip CNT cathodes have been intensively studied in the last few decades, a systematic study of the influencing factors on the electron beam properties of CNT cold cathodes and the resolution of the secondary electron images has been overlooked in this field. Here, we have systematically investigated the effect of the structural properties of a CNT cold cathode on the electron beam properties and resolution of secondary electron microscope (SEM) images. The aspect ratio (geometric factor) and the diameter of the tip of a vertically standing CNT cold cathode significantly affect the electron beam properties, including the beam size and brightness, and consequently determine the resolution of the secondary electron images obtained by SEM systems equipped with a CNT cold cathode module. Theoretical simulation elucidated the dependence of the structural features of CNT cold cathodes and electron beam properties on the contribution of edge-emitted electrons to the total field emission current. Investigating the correlations between the structural properties of CNT cold cathodes, the properties of the emitted electron beams, and the resolution of the secondary electron images captured by SEM equipped with CNT cold cathode modules is highly important and informative as a basic model.
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Affiliation(s)
- Ha Rim Lee
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 024471, Korea; (H.R.L.); (D.W.K.); (A.R.)
- Advanced Instrumentation Institute, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea;
| | - Da Woon Kim
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 024471, Korea; (H.R.L.); (D.W.K.); (A.R.)
| | - Alfi Rodiansyah
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 024471, Korea; (H.R.L.); (D.W.K.); (A.R.)
| | - Boklae Cho
- Advanced Instrumentation Institute, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea;
| | - Joonwon Lim
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 024471, Korea; (H.R.L.); (D.W.K.); (A.R.)
| | - Kyu Chang Park
- Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 024471, Korea; (H.R.L.); (D.W.K.); (A.R.)
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Li M, Wang Q, Xu J, Zhang J, Qi Z, Zhang X. Optically Induced Field-Emission Source Based on Aligned Vertical Carbon Nanotube Arrays. Nanomaterials (Basel) 2021; 11:nano11071810. [PMID: 34361196 PMCID: PMC8308351 DOI: 10.3390/nano11071810] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/06/2021] [Accepted: 07/09/2021] [Indexed: 11/29/2022]
Abstract
Due to the high field enhancement factor and photon-absorption efficiency, carbon nanotubes (CNTs) have been widely used in optically induced field-emission as a cathode. Here, we report vertical carbon nanotube arrays (VCNTAs) that performed as high-density electron sources. A combination of high applied electric field and laser illumination made it possible to modulate the emission with laser pulses. When the bias electric field and laser power density increased, the emission process is sensitive to a power law of the laser intensity, which supports the emission mechanism of optically induced field emission followed by over-the-barrier emission. Furthermore, we determine a polarization dependence that exhibits a cosine behavior, which verifies the high possibility of optically induced field emission.
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Bertolini G, Gürlü O, Pröbsting R, Westholm D, Wei J, Ramsperger U, Zanin DA, Cabrera H, Pescia D, Xanthakis JP, Schnedler M, Dunin-Borkowski RE. Non-topographic current contrast in scanning field emission microscopy. R Soc Open Sci 2021; 8:210511. [PMID: 34295530 PMCID: PMC8278050 DOI: 10.1098/rsos.210511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
In scanning field emission microscopy (SFEM), a tip (the source) is approached to few (or a few tens of) nanometres distance from a surface (the collector) and biased to field-emit electrons. In a previous study (Zanin et al. 2016 Proc. R. Soc. A 472, 20160475. (doi:10.1098/rspa.2016.0475)), the field-emitted current was found to change by approximately 1% at a monatomic surface step (approx. 200 pm thick). Here we prepare surface domains of adjacent different materials that, in some instances, have a topographic contrast smaller than 15 pm. Nevertheless, we observe a contrast in the field-emitted current as high as 10%. This non-topographic collector material dependence is a yet unexplored degree of freedom calling for a new understanding of the quantum mechanical tunnelling barrier at the source site that takes into account the properties of the material at the collector site.
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Affiliation(s)
- G. Bertolini
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - O. Gürlü
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - R. Pröbsting
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - D. Westholm
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - J. Wei
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - U. Ramsperger
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - D. A. Zanin
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - H. Cabrera
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - D. Pescia
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - J. P. Xanthakis
- Electrical and Computer Engineering Department, National Technical University of Athens, Athens 15700, Greece
| | - M. Schnedler
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - R. E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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36
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Zhang J, Wei J, Li D, Zhang H, Wang Y, Zhang X. A Cylindrical Triode Ultrahigh Vacuum Ionization Gauge with a Carbon Nanotube Cathode. Nanomaterials (Basel) 2021; 11:nano11071636. [PMID: 34206531 PMCID: PMC8306528 DOI: 10.3390/nano11071636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 11/23/2022]
Abstract
In this study, a cylindrical triode ultrahigh vacuum ionization gauge with a screen-printed carbon nanotube (CNT) electron source was developed, and its metrological performance in different gases was systematically investigated using an ultrahigh vacuum system. The resulting ionization gauge with a CNT cathode responded linearly to nitrogen, argon, and air pressures in the range from ~4.0 ± 1.0 × 10−7 to 6 × 10−4 Pa, which is the first reported CNT emitter-based ionization gauge whose lower limit of pressure measurement is lower than its hot cathode counterpart. In addition, the sensitivities of this novel gauge were ~0.05 Pa−1 for nitrogen, ~0.06 Pa−1 for argon, and ~0.04 Pa−1 for air, respectively. The trend of sensitivity with anode voltage, obtained by the experimental method, was roughly consistent with that gained through theoretical simulation. The advantages of the present sensor (including low power consumption for electron emissions, invisible to infrared light radiation and thermal radiation, high stability, etc.) mean that it has potential applications in space exploration.
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Affiliation(s)
- Jian Zhang
- School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China;
| | - Jianping Wei
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China; (J.W.); (D.L.); (H.Z.)
| | - Detian Li
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China; (J.W.); (D.L.); (H.Z.)
| | - Huzhong Zhang
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China; (J.W.); (D.L.); (H.Z.)
| | - Yongjun Wang
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China; (J.W.); (D.L.); (H.Z.)
- Correspondence: (Y.W.); (X.Z.)
| | - Xiaobing Zhang
- School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China;
- Correspondence: (Y.W.); (X.Z.)
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Rughoobur G, Jain L, Akinwande AI. Electron transmission through suspended graphene membranes measured with a low-voltage gated Si field emitter array. Nanotechnology 2021; 32:285201. [PMID: 33831850 DOI: 10.1088/1361-6528/abf5fb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
We experimentally demonstrate the transmission of electrons through different number (1, 2, and 5) of suspended graphene layers at electron energies between 20 and 250 eV. Electrons with initial energies lower than 40 eV are generated using silicon field emitter arrays with 1μm pitch, and accelerated towards the graphene layers supported by a silicon nitride grid biased at voltages from -20 to 200 V. We measured significant increase in current collected at the anode with the presence of graphene, which is attributed to the possible generation of secondary electrons by primary electrons impinging on the graphene membrane. Highest output current was recorded with monolayer graphene at approximately 90 eV, with up to 1.7 times the incident current. The transparency of graphene to low-energy electrons and its impermeability to gas molecules could enable low-voltage field emission electron sources, which often require ultra-high vacuum, to operate in a relatively poor vacuum environment.
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Affiliation(s)
- Girish Rughoobur
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, 60 Vassar Street, Cambridge, MA 02139, United States of America
| | - Lay Jain
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, 60 Vassar Street, Cambridge, MA 02139, United States of America
| | - Akintunde I Akinwande
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, 60 Vassar Street, Cambridge, MA 02139, United States of America
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Abstract
The III-nitride semiconductors have many attractive properties for field-emission vacuum electronics, including high thermal and chemical stability, low electron affinity, and high breakdown fields. Here, we report top-down fabricated gallium nitride (GaN)-based nanoscale vacuum electron diodes operable in air, with record ultralow turn-on voltages down to ∼0.24 V and stable high field-emission currents, tested up to several microamps for single-emitter devices. We leverage a scalable, top-down GaN nanofabrication method leading to damage-free and smooth surfaces. Gap-dependent and pressure-dependent studies provide new insights into the design of future, integrated nanogap vacuum electron devices. The results show promise for a new class of high-performance and robust, on-chip, III-nitride-based vacuum nanoelectronics operable in air or reduced vacuum.
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Affiliation(s)
- Keshab R Sapkota
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - François Leonard
- Sandia National Laboratories, Livermore, California 94551, United States
| | - A Alec Talin
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Brendan P Gunning
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Barbara A Kazanowska
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Kevin S Jones
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - George T Wang
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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Ahmed R, Urban R, Salomons M, Cloutier M, Mizuno S, Wolkow R, Pitters J. Field Assisted Reactive Gas Etching of Multiple Tips Observed using FIM. Ultramicroscopy 2021; 223:113216. [PMID: 33596521 DOI: 10.1016/j.ultramic.2021.113216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/19/2021] [Indexed: 11/22/2022]
Abstract
A simple and cost effective method to fabricate multiple tungsten (W) single atom tips (SATs) from both poly and single crystalline wires is reported. Two or four tips attached to a holder are electrochemically etched together in NaOH solution followed by a controlled field assisted reactive gas etching in vacuum using nitrogen as an etching gas and helium as an imaging gas. A Common high voltage is applied simultaneously to all nanotips to shape the apexes towards single atoms. Single atom tips were achieved for both W(111) and W(110) while trimer tips were also achieved for W(111). This observation can lead to an important step towards realizing simplified etching processes of multiple tips which in turn can help to simultaneously fabricate numerous tips leading to mass fabrication and characterization.
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Li X, Lou C, Li W, Wang L, Gao F, Shao G, Chen S, Yang W. High-Performance Field Emitters Based on SiC Nanowires with Designed Electron Emission Sites. ACS Appl Mater Interfaces 2021; 13:3062-3069. [PMID: 33405499 DOI: 10.1021/acsami.0c20694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Making field emitters with both low turn-on field (Eto) and high current emission stability is one of the keys to push forward their practical applications. In the present work, we report the exploration of high-performance field emitters with designed sharp corners around SiC nanowires for fundamentally enhanced electron emission sites. The sharp corners with tailored densities are rationally created based on a facile etching technique. Accordingly, the emission sites and nanowires are integrated into a single-crystalline configuration without interfaces, which could offer the emitters with a robust structure to avoid the structural damage induced by the generated Joule heat and electrostatic forces over long-term field emission (FE) operation. Consequently, the Eto of the as-fabricated SiC field emitter is low down to 0.52 V/μm, which is comparable to the state-of-the-art one ever reported. Moreover, they have high electron emission stability with a current fluctuation of just 2% over 10 h, representing their promising applications in FE-based electronic units.
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Affiliation(s)
- Xiaoxiao Li
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. China
- School of Materials Science and Engineering, Shandong University, Jinan 250061, P. R. China
| | - Chenxuan Lou
- Department of Physics, Beijing Normal University, Beijing 100875, P. R. China
| | - Weijun Li
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. China
| | - Lin Wang
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. China
| | - Fengmei Gao
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. China
| | - Gang Shao
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Shanliang Chen
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. China
| | - Weiyou Yang
- Institute of Materials, Ningbo University of Technology, Ningbo 315211, P. R. 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 (Basel) 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Yang K, Liu J, Jiang R, Gong Y, Zeng B, Yang J, Chi F, Liu L. Maximizing the Field Emission Performance of Graphene Arrays. Nanomaterials (Basel) 2020; 10:E2003. [PMID: 33050566 PMCID: PMC7599458 DOI: 10.3390/nano10102003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/26/2020] [Accepted: 10/05/2020] [Indexed: 11/23/2022]
Abstract
To design efficient and powerful field emission cathodes, the screening effect is of great importance and should be traded off between screening and emitter number. It has long been found that to achieve maximum emission efficiency in an array, neighboring emitters are at two or three times their height from each other. However, this is only true for one-dimensional emitters, such as carbon nanotubes, but for graphene, a two-dimensional material, it is different. In this work, we found that to achieve maximum emission efficiency in an array of graphene, the separation of the emitter is four times the height, and it is insensitive to the anode voltage and the distance between the cathode and the anode.
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Affiliation(s)
- Kaiqiang Yang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (K.Y.); (J.L.); (R.J.); (Y.G.)
- Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (J.Y.); (F.C.)
| | - Jianlong Liu
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (K.Y.); (J.L.); (R.J.); (Y.G.)
| | - Ruirui Jiang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (K.Y.); (J.L.); (R.J.); (Y.G.)
| | - Yubing Gong
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (K.Y.); (J.L.); (R.J.); (Y.G.)
| | - Baoqing Zeng
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (K.Y.); (J.L.); (R.J.); (Y.G.)
| | - Jianjun Yang
- Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (J.Y.); (F.C.)
| | - Feng Chi
- Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (J.Y.); (F.C.)
| | - Liming Liu
- Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (J.Y.); (F.C.)
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Shen CL, Yang SM, Lu KC. Single Crystalline Higher Manganese Silicide Nanowire Arrays with Outstanding Physical Properties through Double Tube Chemical Vapor Deposition. Nanomaterials (Basel) 2020; 10:E1880. [PMID: 32961744 DOI: 10.3390/nano10091880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 11/17/2022]
Abstract
In this work, we report a novel and efficient silicidation method to synthesize higher manganese silicide (HMS) nanowires with interesting characterization and physical properties. High density silicon nanowire arrays fabricated by chemical etching reacted with MnCl2 precursor through a unique double tube chemical vapor deposition (CVD) system, where we could enhance the vapor pressure of the precursor and provide stable Mn vapor with a sealing effect. It is crucial that the method enables the efficient formation of high quality higher manganese silicide nanowires without a change in morphology and aspect ratio during the process. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to characterize the HMS nanowires. High-resolution TEM studies confirm that the HMS nanowires were single crystalline Mn27Si47 nanowires of Nowotny Chimney Ladder crystal structures. Magnetic property measurements show that the Mn27Si47 nanowire arrays were ferromagnetic at room temperature with a Curie temperature of over 300 K, highly depending on the relationship between the direction of the applied electric field and the axial direction of the standing nanowire arrays. Field emission measurements indicate that the 20 μm long nanowires possessed a field enhancement factor of 3307. The excellent physical properties of the HMS nanowires (NWs) make them attractive choices for applications in spintronic devices and field emitters.
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Grillo A, Passacantando M, Zak A, Pelella A, Di Bartolomeo A. WS 2 Nanotubes: Electrical Conduction and Field Emission Under Electron Irradiation and Mechanical Stress. Small 2020; 16:e2002880. [PMID: 32761781 DOI: 10.1002/smll.202002880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/08/2020] [Indexed: 06/11/2023]
Abstract
This study reports the electrical transport and the field emission properties of individual multi-walled tungsten disulphide (WS2 ) nanotubes (NTs) under electron beam irradiation and mechanical stress. Electron beam irradiation is used to reduce the nanotube-electrode contact resistance by one-order of magnitude. The field emission capability of single WS2 NTs is investigated, and a field emission current density as high as 600 kA cm-2 is attained with a turn-on field of ≈100 V μm-1 and field-enhancement factor ≈50. Moreover, the electrical behavior of individual WS2 NTs is studied under the application of longitudinal tensile stress. An exponential increase of the nanotube resistivity with tensile strain is demonstrated up to a recorded elongation of 12%, thereby making WS2 NTs suitable for piezoresistive strain sensor applications.
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Affiliation(s)
- Alessandro Grillo
- Physics Department "E. R. Caianiello" and Interdepartmental centre NanoMates, University of Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
- CNR-SPIN Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
| | - Maurizio Passacantando
- Department of Physical and Chemical Sciences, University of L'Aquila, and CNR-SPIN L'Aquila, via Vetoio, Coppito, 67100, Italy
| | - Alla Zak
- Faculty of Sciences, HIT-Holon Institute of Technology, Holon, 5810201, Israel
| | - Aniello Pelella
- Physics Department "E. R. Caianiello" and Interdepartmental centre NanoMates, University of Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
- CNR-SPIN Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
| | - Antonio Di Bartolomeo
- Physics Department "E. R. Caianiello" and Interdepartmental centre NanoMates, University of Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
- CNR-SPIN Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
- INFN-Gruppo collegato di Salerno, via Giovanni Paolo II n. 132, Fisciano, 84084, Italy
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Laszczyk KU. Field Emission Cathodes to Form an Electron Beam Prepared from Carbon Nanotube Suspensions. Micromachines (Basel) 2020; 11:mi11030260. [PMID: 32121329 PMCID: PMC7142948 DOI: 10.3390/mi11030260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 11/16/2022]
Abstract
In the first decade of our century, carbon nanotubes (CNTs) became a wonderful emitting material for field-emission (FE) of electrons. The carbon nanotube field-emission (CNT-FE) cathodes showed the possibility of low threshold voltage, therefore low power operation, together with a long lifetime, high brightness, and coherent beams of electrons. Thanks to this, CNT-FE cathodes have come ahead of increasing demand for novel self-sustaining and miniaturized devices performing as X-ray tubes, X-ray spectrometers, and electron microscopes, which possess low weight and might work without the need of the specialized equipped room, e.g., in a harsh environment and inaccessible-so-far areas. In this review, the author discusses the current state of CNT-FE cathode research using CNT suspensions. Included in this review are the basics of cathode operation, an evaluation, and fabrication techniques. The cathodes are compared based on performance and correlated issues. The author includes the advancement in field-emission enhancement by postprocess treatments, incorporation of fillers, and the use of film coatings with lower work functions than that of CNTs. Each approach is discussed in the context of the CNT-FE cathode operating factors. Finally, we discuss the issues and perspectives of the CNT-FE cathode research and development.
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Affiliation(s)
- Karolina Urszula Laszczyk
- Wroclaw University of Science and Technology, Faculty of Microelectronic System and Photonics, 50-370 Wroclaw, Poland
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Chen CY, Jiang JR, Chuang WS, Liu MS, Lee SW. Development of Crystalline Cu 2S Nanowires via a Direct Synthesis Process and Its Potential Applications. Nanomaterials (Basel) 2020; 10:nano10020399. [PMID: 32102394 PMCID: PMC7075312 DOI: 10.3390/nano10020399] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/12/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022]
Abstract
Large-scale and uniform copper(I) sulfide (Cu2S) nanowires have been successfully synthesized via a cheap, fast, easily handled, and environmentally friendly approach. In addition to the reductive properties of the biomolecule-assisted method, they also have a strong shape- or size-directing functionality in the reaction process. The field-emission properties of the Cu2S nanowires in a vacuum were studied by the Folwer–Nordheim (F–N) theory. The Cu2S nanowires have a low turn-on field at 1.19 V/μm and a high enhancement factor (β) of 19,381. The photocatalytic degradation of Cu2S nanowires was investigated by the change in the concentrations of rhodamine B (RhB) under UV illumination. These outstanding results of Cu2S nanowires indicate that they will be developed as good candidates as electron field emitters and chemical photocatalysts in future nanoelectronic devices.
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Affiliation(s)
- Chih-Yen Chen
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
- Correspondence: (C.-Y.C.); (S.-W.L.)
| | - Jian-Ru Jiang
- Institute of Materials Science and Engineering, National Central University, Taoyuan 320, Taiwan
| | - Wen-Shuo Chuang
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Ming-Song Liu
- Institute of Materials Science and Engineering, National Central University, Taoyuan 320, Taiwan
| | - Sheng-Wei Lee
- Institute of Materials Science and Engineering, National Central University, Taoyuan 320, Taiwan
- Correspondence: (C.-Y.C.); (S.-W.L.)
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Iemmo L, Urban F, Giubileo F, Passacantando M, Di Bartolomeo A. Nanotip Contacts for Electric Transport and Field Emission Characterization of Ultrathin MoS 2 Flakes. Nanomaterials (Basel) 2020; 10:E106. [PMID: 31947985 DOI: 10.3390/nano10010106] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 11/21/2022]
Abstract
We report a facile approach based on piezoelectric-driven nanotips inside a scanning electron microscope to contact and electrically characterize ultrathin MoS2 (molybdenum disulfide) flakes on a SiO2/Si (silicon dioxide/silicon) substrate. We apply such a method to analyze the electric transport and field emission properties of chemical vapor deposition-synthesized monolayer MoS2, used as the channel of back-gate field effect transistors. We study the effects of the gate-voltage range and sweeping time on the channel current and on its hysteretic behavior. We observe that the conduction of the MoS2 channel is affected by trap states. Moreover, we report a gate-controlled field emission current from the edge part of the MoS2 flake, evidencing a field enhancement factor of approximately 200 and a turn-on field of approximately 40 V/μm at a cathode–anode separation distance of 900 nm.
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Zu Y, Yuan X, Xu X, Cole MT, Zhang Y, Li H, Yin Y, Wang B, Yan Y. Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode. Nanomaterials (Basel) 2019; 9:nano9121768. [PMID: 31842262 PMCID: PMC6955727 DOI: 10.3390/nano9121768] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 11/16/2022]
Abstract
Carbon nanotube (CNT) cold cathodes are proving to be compelling candidates for miniaturized terahertz (THz) vacuum electronic devices (VEDs) owning to their superior field-emission (FE) characteristics. Here, we report on the development of a multi-sheet beam CNT cold cathode electron optical system with concurrently high beam current and high current density. The microscopic FE characteristics of the CNT film emitter is captured through the development of an empirically derived macroscopic simulation model which is used to provide representative emission performance. Through parametrically optimized macroscale simulations, a five-sheet-beam triode electron gun has been designed, and has been shown to emit up to 95 mA at 3.2 kV. Through careful engineering of the electron gun geometric parameters, a low-voltage compact THz radiation source operating in high-order TM5,1 mode is investigated to improve output power and suppress mode competition. Particle in cell (PIC) simulations show the average output power is 33 W at 0.1 THz, and the beam–wave interaction efficiency is approximately 10%.
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Affiliation(s)
- Yifan Zu
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
| | - Xuesong Yuan
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
- Correspondence:
| | - Xiaotao Xu
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
| | - Matthew T. Cole
- Department of Electronic and Electrical Engineering, University of Bath, North Road, Bath BA2 7AY, UK;
| | - Yu Zhang
- State Key Laboratory Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China;
| | - Hailong Li
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
| | - Yong Yin
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
| | - Bin Wang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
| | - Yang Yan
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (Y.Z.); (X.X.); (H.L.); (Y.Y.); (B.W.); (Y.Y.)
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Chang WT, Hsu HJ, Pao PH. Vertical Field Emission Air-Channel Diodes and Transistors. Micromachines (Basel) 2019; 10:mi10120858. [PMID: 31817757 PMCID: PMC6952975 DOI: 10.3390/mi10120858] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/27/2019] [Accepted: 12/05/2019] [Indexed: 11/16/2022]
Abstract
Vacuum channel transistors are potential candidates for low-loss and high-speed electronic devices beyond complementary metal-oxide-semiconductors (CMOS). When the nanoscale transport distance is smaller than the mean free path (MFP) in atmospheric pressure, a transistor can work in air owing to the immunity of carrier collision. The nature of a vacuum channel allows devices to function in a high-temperature radiation environment. This research intended to investigate gate location in a vertical vacuum channel transistor. The influence of scattering under different ambient pressure levels was evaluated using a transport distance of about 60 nm, around the range of MFP in air. The finite element model suggests that gate electrodes should be near emitters in vertical vacuum channel transistors because the electrodes exhibit high-drive currents and low-subthreshold swings. The particle trajectory model indicates that collected electron flow (electric current) performs like a typical metal oxide semiconductor field effect-transistor (MOSFET), and that gate voltage plays a role in enhancing emission electrons. The results of the measurement on vertical diodes show that current and voltage under reduced pressure and filled with CO2 are different from those under atmospheric pressure. This result implies that this design can be used for gas and pressure sensing.
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50
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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. Adv Mater 2019; 31:e1805845. [PMID: 30724407 DOI: 10.1002/adma.201805845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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