1
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Yadgarov L, Tenne R. Nanotubes from Transition Metal Dichalcogenides: Recent Progress in the Synthesis, Characterization and Electrooptical Properties. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400503. [PMID: 38953349 DOI: 10.1002/smll.202400503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 06/02/2024] [Indexed: 07/04/2024]
Abstract
Inorganic layered compounds (2D-materials), particularly transition metal dichalcogenide (TMDC), are the focus of intensive research in recent years. Shortly after the discovery of carbon nanotubes (CNTs) in 1991, it was hypothesized that nanostructures of 2D-materials can also fold and seam forming, thereby nanotubes (NTs). Indeed, nanotubes (and fullerene-like nanoparticles) of WS2 and subsequently from MoS2 were reported shortly after CNT. However, TMDC nanotubes received much less attention than CNT until recently, likely because they cannot be easily produced as single wall nanotubes with well-defined chiral angles. Nonetheless, NTs from inorganic layered compounds have become a fertile field of research in recent years. Much progress has been achieved in the high-temperature synthesis of TMDC nanotubes of different kinds, as well as their characterization and the study of their properties and potential applications. Their multiwall structure is found to be a blessing rather than a curse, leading to intriguing observations. This concise minireview is dedicated to the recent progress in the research of TMDC nanotubes. After reviewing the progress in their synthesis and structural characterization, their contributions to the research fields of energy conversion and storage, polymer nanocomposites, andunique optoelectronic devices are being reviewed. These studies suggest numerous potential applications for TMDC nanotubes in various technologies, which are briefly discussed.
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Affiliation(s)
- Lena Yadgarov
- The Department of Chemical Engineering, Ariel University, Ramat HaGolan St 65, Ariel, 4077625, Israel
| | - Reshef Tenne
- Department of Molecular Chemistry and Materials Science, Weizmann Institute, Hertzl Street 234, Rehovot, 7610010, Israel
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2
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Nerkar SD, Ar SR, Al Mesfer MK, Ansari KB, Khan MS, Deore AB, Attarde RR. Field emission from two-dimensional (2D) CdSSe flake flowers structure grown on gold coated silicon substrate: An efficient cold cathode. Microsc Res Tech 2024. [PMID: 38856214 DOI: 10.1002/jemt.24621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/08/2024] [Accepted: 05/20/2024] [Indexed: 06/11/2024]
Abstract
Field emission finds a vital space in numerous scientific and technological applications, including high-resolution imaging at micro- and nano-scales, conducting high-energy physics experiments, molecule ionization in spectroscopy, and electronic uses. A continuous effort exists to develop new materials for enhanced field emission applications. In the present work, two-dimensional (2D) well-aligned CdSSe flake flowers (CdSSe-FFs) were successfully grown on gold-coated silicon substrate utilizing a simple and affordable chemical bath deposition approach at ambient temperature. The time-dependent growth mechanism from nanoparticles to FFs was observed at optimized parameters such as concentration of precursors, pH (~11), deposition time, and solution temperature. The crystalline nature of CdSSe-FFs is confirmed by high-resolution transmission electron microscopy (HRTEM) results, and selected area electron diffraction (SAED) observations reveal a hexagonal crystal structure. Additionally, the CdSSe-FFs thickness was confirmed by TEM analysis and found to be ~20-30 nm. The optical, photoelectric, and field emission (FE) characteristics are thoroughly explored which shows significant enhancement due to the formation of heterojunction between the gold-coated silicon substrate and CdSSe-FFs. The UV-visible absorption spectra of CdSSe-FFs show enhanced absorption at 700 nm, corresponding to the energy band gap (Eg) of 1.77 eV. The CdSSe-FFs exhibited field emission and photosensitive field emission (PSFE) characteristics. In FE study CdSSe-FFs shows an increase in current density of 387.2 μ A cm-2 in an applied field of 4.1 V m-1 which is 4.08 fold as compared to without light illumination (95.1 μ A cm-2). Furthermore, it shows excellent emission current stability at the preset value of 1.5 μA over 3 h with a deviation of the current density of less than 5% respectively. RESEARCH HIGHLIGHTS: Novel CdSSe flake flowers were grown on Au-coated Si substrate by a cost-effective chemical bath deposition route. The growth mechanism of CdSSe flake flowers is studied in detail. Field emission and Photoluminescence study of CdSSe flake flowers is characterized. CdSSe flake flowers with nanoflakes sharp edges exhibited enhanced field emission properties.
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Affiliation(s)
- Sachin D Nerkar
- Department of Applied Sciences & Humanities, SVKM's Institute of Technology, Dhule, India
| | - Shakeelur Raheman Ar
- Department of Applied Sciences & Humanities, SVKM's Institute of Technology, Dhule, India
| | - Mohammed K Al Mesfer
- Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia
| | - Khursheed B Ansari
- Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia
| | - Mohd Shariq Khan
- Department of Chemical Engineering, College of Engineering, Dhofar University, Salalah, Sultanate of Oman
| | - Amol B Deore
- Department of Applied Science and Humanities, MIT School of Computing, MIT Art, Design and Technology University, Pune, India
| | - R R Attarde
- Department of Physics, Pankaj Arts and Science College Chopda, Jalgaon, India
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3
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Wu D, Wang Y, Xiao J, Hu J, Zhao X, Gao Y, Yuan J, Wang W. Surface lattice resonances enhanced directional amplified spontaneous emission on plasmonic honeycomb nanocone array. Phys Chem Chem Phys 2023; 25:26847-26852. [PMID: 37782475 DOI: 10.1039/d3cp03718e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Plasmonic arrays have emerged as a promising platform for investigating light-matter interactions enhanced by surface lattice resonance (SLR) at the nanoscale, which exhibit superior properties in localized field enhancement, narrow linewidth, and effective radiation loss suppression. In this study, an Al nanocone array in a honeycomb arrangement served as an optical cavity with a tip effect to realize the directional and polarized amplified spontaneous emission (ASE) of R6G. Based on the optical feedback between the degenerated SLR mode of high local density of states (LDOS) and the emission of gain media, 140-fold enhanced ASE was observed at an emission angle of 25° under TM polarization when the pump power density exceeded the threshold of 197.8 W cm-2. Moreover, polarization-resolved iso-frequency images indicated that a specific polarization dependence of ASE was modulated by the SLR mode. This study clarifies the interaction between the gain media and plasmonic system, which is beneficial for the generation of nanolasing with directional emission and lays a foundation for the plasmonic device.
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Affiliation(s)
- Dongda Wu
- College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China.
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Yi Wang
- College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China.
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Jiamin Xiao
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Jiang Hu
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Xuchao Zhao
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Yuhao Gao
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Jiazhi Yuan
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
| | - Wenxin Wang
- College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China.
- Qingdao Innovation and Development Center of Harbin Engineering University, Harbin Engineering University, Qingdao 266500, China
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4
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Chen Y, Chen J, Li Z. Cold Cathodes with Two-Dimensional van der Waals Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2437. [PMID: 37686945 PMCID: PMC10490007 DOI: 10.3390/nano13172437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/07/2023] [Accepted: 08/14/2023] [Indexed: 09/10/2023]
Abstract
Two-dimensional van der Waals materials could be used as electron emitters alone or stacked in a heterostructure. Many significant phenomena of two-dimensional van der Waals field emitters have been observed and predicted since the landmark discovery of graphene. Due to the wide variety of heterostructures that integrate an atomic monolayer or multilayers with insulator nanofilms or metallic cathodes by van der Waals force, the diversity of van der Waals materials is large to be chosen from, which are appealing for further investigation. Until now, increasing the efficiency, stability, and uniformity in electron emission of cold cathodes with two-dimensional materials is still of interest in research. Some novel behaviors in electron emission, such as coherence and directionality, have been revealed by the theoretical study down to the atomic scale and could lead to innovative applications. Although intensive emission in the direction normal to two-dimensional emitters has been observed in experiments, the theoretical mechanism is still incomplete. In this paper, we will review some late progresses related to the cold cathodes with two-dimensional van der Waals materials, both in experiments and in the theoretical study, emphasizing the phenomena which are absent in the conventional cold cathodes. The review will cover the fabrication of several kinds of emitter structures for field emission applications, the state of the art of their field emission properties and the existing field emission model. In the end, some perspectives on their future research trend will also be given.
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Affiliation(s)
- Yicong Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technologies, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technologies, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zhibing Li
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Science, Sun Yat-Sen University, Shenzhen 518000, China
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5
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Song I. Novel electrodes and gate dielectrics for
field‐effect
transistors based on
two‐dimensional
materials. B KOREAN CHEM SOC 2023. [DOI: 10.1002/bkcs.12686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Affiliation(s)
- Intek Song
- Department of Applied Chemistry Andong National University (ANU) Andong Gyeongbuk Republic of Korea
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Cho U, Kim S, Shin CY, Song I. Tabletop Fabrication of High-Performance MoS 2 Field-Effect Transistors. ACS OMEGA 2022; 7:21220-21224. [PMID: 35755343 PMCID: PMC9219050 DOI: 10.1021/acsomega.2c02188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
A simple way to prepare field-effect transistors (FETs) using MoS2 on tabletop is presented. Conductive silver paste was applied onto chemical vapor deposition (CVD)-grown MoS2 as Ohmic-contact electrodes. Heating the device in vacuum further enhances the performance without damage. The final performance is comparable to that of the SiO2-backgated devices prepared by lithography and metal evaporators. The role of the silver paste and heat treatment in vacuum is investigated by device and spectroscopic analysis.
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7
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Superconducting- and Graphene-Based Devices. NANOMATERIALS 2022; 12:nano12122055. [PMID: 35745392 PMCID: PMC9229232 DOI: 10.3390/nano12122055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 12/10/2022]
Abstract
This Special Issue has been organized to collect new or improved ideas regarding the exploitation of superconducting materials, as well as graphene, aiming to develop innovative devices [...].
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8
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Giubileo F, Bartolomeo AD, Zhong Y, Zhao S, Passacantando M. Field emission from AlGaN nanowires with low turn-on field. NANOTECHNOLOGY 2020; 31:475702. [PMID: 32885788 DOI: 10.1088/1361-6528/abaf22] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We fabricate AlGaN nanowires by molecular beam epitaxy and we investigate their field emission properties by means of an experimental setup using nano-manipulated tungsten tips as electrodes, inside a scanning electron microscope. The tip-shaped anode gives access to local properties, and allows collecting electrons emitted from areas as small as 1 µm2. The field emission characteristics are analysed in the framework of Fowler-Nordheim theory and we find a field enhancement factor as high as β = 556 and a minimum turn-on field [Formula: see text] = 17 V µm-1 for a cathode-anode separation distance [Formula: see text] = 500 nm. We show that for increasing separation distance, [Formula: see text] increases up to about 35 V µm-1 and β decreases to ∼100 at [Formula: see text] = 1600 nm. We also demonstrate the time stability of the field emission current from AlGaN nanowires for several minutes. Finally, we explain the observation of modified slope of the Fowler-Nordheim plots at low fields in terms of non-homogeneous field enhancement factors due to the presence of protruding emitters.
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Affiliation(s)
- Filippo Giubileo
- CNR-SPIN Salerno, via Giovanni Paolo II n. 132, Fisciano 84084, Italy
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9
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Di Bartolomeo A, Urban F, Pelella A, Grillo A, Passacantando M, Liu X, Giubileo F. Electron irradiation of multilayer [Formula: see text] field effect transistors. NANOTECHNOLOGY 2020; 31:375204. [PMID: 32428882 DOI: 10.1088/1361-6528/ab9472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Palladium diselenide ([Formula: see text]) is a recently isolated layered material that has attracted a lot of interest for its pentagonal structure, air stability and electrical properties that are largely tunable by the number of layers. In this work, multilayer [Formula: see text] is used as the channel of back-gate field-effect transistors, which are studied under repeated electron irradiations. Source-drain [Formula: see text] electrodes enable contacts with resistance below [Formula: see text]. The transistors exhibit a prevailing n-type conduction in high vacuum, which reversibly turns into ambipolar electric transport at atmospheric pressure. Irradiation by [Formula: see text] electrons suppresses the channel conductance and promptly transforms the device from n-type to p-type. An electron fluence as low as [Formula: see text] dramatically changes the transistor behavior, demonstrating a high sensitivity of [Formula: see text] to electron irradiation. The sensitivity is lost after a few exposures, with a saturation condition being reached for fluence higher than [Formula: see text]. The damage induced by high electron fluence is irreversible as the device persists in the radiation-modified state for several hours, if kept in vacuum and at room temperature. With the support of numerical simulation, we explain such a behavior by electron-induced Se atom vacancy formation and charge trapping in slow trap states at the [Formula: see text] interface.
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Affiliation(s)
- A Di Bartolomeo
- Department of Physics, University of Salerno, via Giovanni Paolo II, Fisciano 84084, Italy. CNR-SPIN Salerno, via Giovanni Paolo II, Fisciano 84084, Italy
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10
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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 (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002880. [PMID: 32761781 DOI: 10.1002/smll.202002880] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [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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11
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Di Bartolomeo A. Emerging 2D Materials and Their Van Der Waals Heterostructures. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E579. [PMID: 32235754 PMCID: PMC7153384 DOI: 10.3390/nano10030579] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
Two-dimensional (2D) materials and their van der Waals heterojunctions offer the opportunity to combine layers with different properties as the building blocks to engineer new functional materials for high-performance devices, sensors, and water-splitting photocatalysts. A tremendous amount of work has been done thus far to isolate or synthesize new 2D materials as well as to form new heterostructures and investigate their chemical and physical properties. This article collection covers state-of-the-art experimental, numerical, and theoretical research on 2D materials and on their van der Waals heterojunctions for applications in electronics, optoelectronics, and energy generation.
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Affiliation(s)
- Antonio Di Bartolomeo
- Physics Department "E.R.Caianiello" and "Interdepartmental center NANOMATES", University of Salerno, Fisciano, 84084 Salerno, Italy
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12
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Grillo A, Di Bartolomeo A, Urban F, Passacantando M, Caridad JM, Sun J, Camilli L. Observation of 2D Conduction in Ultrathin Germanium Arsenide Field-Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12998-13004. [PMID: 32100522 PMCID: PMC7997104 DOI: 10.1021/acsami.0c00348] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report the fabrication and electrical characterization of germanium arsenide (GeAs) field-effect transistors with ultrathin channels. The electrical transport is investigated in the 20-280 K temperature range, revealing that the p-type electrical conductivity and the field-effect mobility are growing functions of temperature. An unexpected peak is observed in the temperature dependence of the carrier density per area at ∼75 K. Such a feature is explained considering that the increased carrier concentration at higher temperatures and the vertical band bending combined with the gate field lead to the formation of a two-dimensional (2D) conducting channel, limited to few interfacial GeAs layers, which dominates the channel conductance. The conductivity follows the variable-range hopping model at low temperatures and becomes the band-type at higher temperatures when the 2D channel is formed. The formation of the 2D channel is validated through a numerical simulation that shows excellent agreement with the experimental data.
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Affiliation(s)
- Alessandro Grillo
- Physics Department
“E. R. Caianiello”, 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”, University
of Salerno, via Giovanni Paolo II n. 132, Fisciano 84084, Italy
- CNR-SPIN
Salerno, via Giovanni
Paolo II n. 132, Fisciano 84084, Italy
| | - Francesca Urban
- Physics Department
“E. R. Caianiello”, 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 Science, University of L’Aquila
and CNR-SPIN L’Aquila, via Vetoio, L’Aquila 67100, Coppito, Italy
| | - Jose M. Caridad
- Department of Physics, Technical University
of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Jianbo Sun
- Department of Physics, Technical University
of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Luca Camilli
- Department of Physics, Technical University
of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
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13
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Urban F, Lupina G, Grillo A, Martucciello N, Di Bartolomeo A. Contact resistance and mobility in back-gate graphene transistors. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/ab7055] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
The metal-graphene contact resistance is one of the major limiting factors toward the technological exploitation of graphene in electronic devices and sensors. High contact resistance can be detrimental to device performance and spoil the intrinsic great properties of graphene. In this paper, we fabricate back-gate graphene field-effect transistors with different geometries to study the contact and channel resistance as well as the carrier mobility as a function of gate voltage and temperature. We apply the transfer length method and the y-function method showing that the two approaches can complement each other to evaluate the contact resistance and prevent artifacts in the estimation of carrier mobility dependence on the gate-voltage. We find that the gate voltage modulates both the contact and the channel resistance in a similar way but does not change the carrier mobility. We also show that raising the temperature lowers the carrier mobility, has a negligible effect on the contact resistance, and can induce a transition from a semiconducting to a metallic behavior of the graphene sheet resistance, depending on the applied gate voltage. Finally, we show that eliminating the detrimental effects of the contact resistance on the transistor channel current almost doubles the carrier field-effect mobility and that a competitive contact resistance as low as 700 Ω·μm can be achieved by the zig-zag shaping of the Ni contact.
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