Special Issue "2D Nanomaterials: Graphene and Beyond Graphene"

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: closed (31 August 2016)

Special Issue Editors

Guest Editor
Prof. Ho Won Jang

Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
Website | E-Mail
Phone: +82-2-880-1720
Fax: +82-2-884-1413
Interests: oxides and 2D materials for chemical sensors; photoelectrodes; nanoelectronics
Guest Editor
Prof. Soo Young Kim

School of Chemical Engineering and Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
Website | E-Mail
Phone: +82-2-820-5875
Fax: +82-2-824-3495
Interests: graphene; metal dichalcogenides; organic/inorganic hybrid perovskite materials; organic light-emitting diodes; organic solar cells

Special Issue Information

Dear Colleagues,

One of grand challenges for next generation materials and devices is the precise design, control, and optimization of material nanostructures to enhance their functionalities in response to the need of emerging technologies. Therefore, the progress in the development of artificial nanostructures or nanoscale materials for novel functionalities that cannot be achieved using traditional materials has been identified as a key to realize electronic, optoelectronic, energy, sensor, bio/medical, environmental, and structural applications of advanced materials. This Special Issue focuses on two-dimensional (2D) nanomaterials, including graphene, boron nitrides, transition metal dichalcogenides, black phosphorus, and metal oxide nanosheets, with emphasis on artificial nanostructuring and tailored heterostructures to create novel functionalities or to significantly enhance existing functionalities. It covers all aspects of 2D nanomaterials, including synthesis, characterization, device fabrication, and simulations for various applications, such as electronics, optoelectronics, catalysis, batteries, fuel cells, sensors, photoelectrochemical cells, thermoelectrics, magnetoelectrics, and water/air purification. We invite the submission of review articles and original research papers from leading groups in the field of 2D nanomaterials.

Prof. Ho Won Jang
Prof. Soo Young Kim
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • 2D nanomaterials
  • graphene
  • graphene oxide
  • transition metal dichalcogenides
  • boron nitride
  • functionalization
  • heterostructures

Published Papers (12 papers)

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Research

Jump to: Review

Open AccessArticle Computational Predictions for Single Chain Chalcogenide-Based One-Dimensional Materials
Nanomaterials 2017, 7(5), 115; doi:10.3390/nano7050115
Received: 9 March 2017 / Revised: 24 April 2017 / Accepted: 2 May 2017 / Published: 17 May 2017
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Abstract
Exfoliation of multilayered materials has led to an abundance of new two-dimensional (2D) materials and to their fabrication by other means. These materials have shown exceptional promise for many applications. In a similar fashion, we can envision starting with crystalline polymeric (multichain) materials
[...] Read more.
Exfoliation of multilayered materials has led to an abundance of new two-dimensional (2D) materials and to their fabrication by other means. These materials have shown exceptional promise for many applications. In a similar fashion, we can envision starting with crystalline polymeric (multichain) materials and exfoliate single-chain, one-dimensional (1D) materials that may also prove useful. We use electronic structure methods to elucidate the properties of such 1D materials: individual chains of chalcogens, of silicon dichalcogenides and of sulfur nitrides. The results indicate reasonable exfoliation energies in the case of polymeric three-dimensional (3D) materials. Quantum confinement effects lead to large band gaps and large exciton binding energies. The effects of strain are quantified and heterojunction band offsets are determined. Possible applications would entail 1D materials on 3D or 2D substrates. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Tuning the Emission Energy of Chemically Doped Graphene Quantum Dots
Nanomaterials 2016, 6(11), 198; doi:10.3390/nano6110198
Received: 22 August 2016 / Revised: 24 October 2016 / Accepted: 28 October 2016 / Published: 3 November 2016
Cited by 2 | PDF Full-text (3322 KB) | HTML Full-text | XML Full-text
Abstract
Tuning the emission energy of graphene quantum dots (GQDs) and understanding the reason of tunability is essential for the GOD function in optoelectronic devices. Besides material-based challenges, the way to realize chemical doping and band gap tuning also pose a serious challenge. In
[...] Read more.
Tuning the emission energy of graphene quantum dots (GQDs) and understanding the reason of tunability is essential for the GOD function in optoelectronic devices. Besides material-based challenges, the way to realize chemical doping and band gap tuning also pose a serious challenge. In this study, we tuned the emission energy of GQDs by substitutional doping using chlorine, nitrogen, boron, sodium, and potassium dopants in solution form. Photoluminescence data obtained from (Cl- and N-doped) GQDs and (B-, Na-, and K-doped) GQDs, respectively exhibited red- and blue-shift with respect to the photoluminescence of the undoped GQDs. X-ray photoemission spectroscopy (XPS) revealed that oxygen functional groups were attached to GQDs. We qualitatively correlate red-shift of the photoluminescence with the oxygen functional groups using literature references which demonstrates that more oxygen containing groups leads to the formation of more defect states and is the reason of observed red-shift of luminescence in GQDs. Further on, time resolved photoluminescence measurements of Cl- and N-GQDs demonstrated that Cl substitution in GQDs has effective role in radiative transition whereas in N-GQDs leads to photoluminescence (PL) quenching with non-radiative transition to ground state. Presumably oxidation or reduction processes cause a change of effective size and the bandgap. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Silver Nanoparticle-Embedded Thin Silica-Coated Graphene Oxide as an SERS Substrate
Nanomaterials 2016, 6(10), 176; doi:10.3390/nano6100176
Received: 13 June 2016 / Revised: 6 September 2016 / Accepted: 6 September 2016 / Published: 22 September 2016
Cited by 1 | PDF Full-text (1769 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A hybrid of Ag nanoparticle (NP)-embedded thin silica-coated graphene oxide (GO@SiO2@Ag NPs) was prepared as a surface-enhanced Raman scattering (SERS) substrate. A 6 nm layer of silica was successfully coated on the surface of GO by the physical adsorption of sodium
[...] Read more.
A hybrid of Ag nanoparticle (NP)-embedded thin silica-coated graphene oxide (GO@SiO2@Ag NPs) was prepared as a surface-enhanced Raman scattering (SERS) substrate. A 6 nm layer of silica was successfully coated on the surface of GO by the physical adsorption of sodium silicate, followed by the hydrolysis of 3-mercaptopropyl trimethoxysilane. Ag NPs were introduced onto the thin silica-coated graphene oxide by the reduction of Ag+ to prepare GO@SiO2@Ag NPs. The GO@SiO2@Ag NPs exhibited a 1.8-fold enhanced Raman signal compared to GO without a silica coating. The GO@SiO2@Ag NPs showed a detection limit of 4-mercaptobenzoic acid (4-MBA) at 0.74 μM. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Investigation of the Band Structure of Graphene-Based Plasmonic Photonic Crystals
Nanomaterials 2016, 6(9), 166; doi:10.3390/nano6090166
Received: 23 July 2016 / Revised: 24 August 2016 / Accepted: 5 September 2016 / Published: 9 September 2016
Cited by 1 | PDF Full-text (4690 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, one-dimensional (1D) and two-dimensional (2D) graphene-based plasmonic photonic crystals (PhCs) are proposed. The band structures and density of states (DOS) have been numerically investigated. Photonic band gaps (PBGs) are found in both 1D and 2D PhCs. Meanwhile, graphene-based plasmonic PhC
[...] Read more.
In this paper, one-dimensional (1D) and two-dimensional (2D) graphene-based plasmonic photonic crystals (PhCs) are proposed. The band structures and density of states (DOS) have been numerically investigated. Photonic band gaps (PBGs) are found in both 1D and 2D PhCs. Meanwhile, graphene-based plasmonic PhC nanocavity with resonant frequency around 175 THz, is realized by introducing point defect, where the chemical potential is from 0.085 to 0.25 eV, in a 2D PhC. Also, the bending wvaguide and the beam splitter are realized by introducing the line defect into the 2D PhC. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle The Effect of Viscous Air Damping on an Optically Actuated Multilayer MoS2 Nanomechanical Resonator Using Fabry-Perot Interference
Nanomaterials 2016, 6(9), 162; doi:10.3390/nano6090162
Received: 14 July 2016 / Revised: 23 August 2016 / Accepted: 30 August 2016 / Published: 5 September 2016
Cited by 1 | PDF Full-text (3503 KB) | HTML Full-text | XML Full-text
Abstract
We demonstrated a multilayer molybdenum disulfide (MoS2) nanomechanical resonator by using optical Fabry-Perot (F-P) interferometric excitation and detection. The thin circular MoS2 nanomembrane with an approximate 8-nm thickness was transferred onto the endface of a ferrule with an inner diameter
[...] Read more.
We demonstrated a multilayer molybdenum disulfide (MoS2) nanomechanical resonator by using optical Fabry-Perot (F-P) interferometric excitation and detection. The thin circular MoS2 nanomembrane with an approximate 8-nm thickness was transferred onto the endface of a ferrule with an inner diameter of 125 μm, which created a low finesse F-P interferometer with a cavity length of 39.92 μm. The effects of temperature and viscous air damping on resonance behavior of the resonator were investigated in the range of −10–80 °C. Along with the optomechanical behavior of the resonator in air, the measured resonance frequencies ranged from 36 kHz to 73 kHz with an extremely low inflection point at 20 °C, which conformed reasonably to those solved by previously obtained thermal expansion coefficients of MoS2. Further, a maximum quality (Q) factor of 1.35 for the resonator was observed at 0 °C due to viscous dissipation, in relation to the lower Knudsen number of 0.0025~0.0034 in the tested temperature range. Moreover, measurements of Q factor revealed little dependence of Q on resonance frequency and temperature. These measurements shed light on the mechanisms behind viscous air damping in MoS2, graphene, and other 2D resonators. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Copper Micro-Labyrinth with Graphene Skin: New Transparent Flexible Electrodes with Ultimate Low Sheet Resistivity and Superior Stability
Nanomaterials 2016, 6(9), 161; doi:10.3390/nano6090161
Received: 15 July 2016 / Revised: 18 August 2016 / Accepted: 31 August 2016 / Published: 1 September 2016
Cited by 1 | PDF Full-text (2356 KB) | HTML Full-text | XML Full-text
Abstract
We have developed self-assembled copper (Cu) micro-labyrinth (ML) with graphene skin for transparent flexible electrodes of optoelectronic devices. The Cu ML is simply formed by heating a thin Cu film with a 100-nm thickness on a SiO2/Si substrate at 950 °C
[...] Read more.
We have developed self-assembled copper (Cu) micro-labyrinth (ML) with graphene skin for transparent flexible electrodes of optoelectronic devices. The Cu ML is simply formed by heating a thin Cu film with a 100-nm thickness on a SiO2/Si substrate at 950 °C under hydrogen ambient to block the oxidation. Moreover, the Cu ML can have graphene skin at the surface by inserting carbo-hydroxyl molecules (CxHy) during heating due to the catalytic decomposition of C–H bonds on the Cu surface. The Cu ML with graphene skin (Cu ML-G) has superior sheet resistivity below 5 Ω/sq and mechanical flexibility without cracks at the bending radius of 0.1 cm. Although the transmittance of Cu ML-G is a little lower (70%~80%) than that of conventional metallic nanowires electrodes (such as Ag, ~90% at the visible wavelength), it has good thermal stability in conductivity without any damage at 200 °C due to a micro-sized pattern and graphene skin which prohibits the surface migration of Cu atoms. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Enhanced End-Contacts by Helium Ion Bombardment to Improve Graphene-Metal Contacts
Nanomaterials 2016, 6(9), 158; doi:10.3390/nano6090158
Received: 23 June 2016 / Revised: 28 July 2016 / Accepted: 29 July 2016 / Published: 26 August 2016
Cited by 1 | PDF Full-text (5973 KB) | HTML Full-text | XML Full-text
Abstract
Low contact resistance between graphene and metals is of paramount importance to fabricate high performance graphene-based devices. In this paper, the impact of both defects induced by helium ion (He+) bombardment and annealing on the contact resistance between graphene and various
[...] Read more.
Low contact resistance between graphene and metals is of paramount importance to fabricate high performance graphene-based devices. In this paper, the impact of both defects induced by helium ion (He+) bombardment and annealing on the contact resistance between graphene and various metals (Ag, Pd, and Pt) were systematically explored. It is found that the contact resistances between all metals and graphene are remarkably reduced after annealing, indicating that not only chemically adsorbed metal (Pd) but also physically adsorbed metals (Ag and Pt) readily form end-contacts at intrinsic defect locations in graphene. In order to further improve the contact properties between Ag, Pd, and Pt metals and graphene, a novel method in which self-aligned He+ bombardment to induce exotic defects in graphene and subsequent thermal annealing to form end-contacts was proposed. By using this method, the contact resistance is reduced significantly by 15.1% and 40.1% for Ag/graphene and Pd/graphene contacts with He+ bombardment compared to their counterparts without He+ bombardment. For the Pt/graphene contact, the contact resistance is, however, not reduced as anticipated with He+ bombardment and this might be ascribed to either inappropriate He+ bombardment dose, or inapplicable method of He+ bombardment in reducing contact resistance for Pt/graphene contact. The joint efforts of as-formed end-contacts and excess created defects in graphene are discussed as the cause responsible for the reduction of contact resistance. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Electrically Tunable Absorption Enhancement with Spectral and Polarization Selectivity through Graphene Plasmonic Light Trapping
Nanomaterials 2016, 6(9), 155; doi:10.3390/nano6090155
Received: 29 June 2016 / Revised: 30 July 2016 / Accepted: 12 August 2016 / Published: 23 August 2016
Cited by 1 | PDF Full-text (1728 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, anisotropic graphene plasmonic structures are explored for light trapping and absorption enhancement in surrounding media. It is shown that electrically tunable and versatile spectral and polarization selectivity can be realized. Particularly, it is possible to control absorption of the incident
[...] Read more.
In this paper, anisotropic graphene plasmonic structures are explored for light trapping and absorption enhancement in surrounding media. It is shown that electrically tunable and versatile spectral and polarization selectivity can be realized. Particularly, it is possible to control absorption of the incident light’s polarization component at a specific wavelength by varying the Fermi energy with suitable geometric designs. It may find applications for new types of infrared and THz photodetectors and will promote the research of other novel polarization devices. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Characteristic Evaluation of Graphene Oxide for Bisphenol A Adsorption in Aqueous Solution
Nanomaterials 2016, 6(7), 128; doi:10.3390/nano6070128
Received: 25 May 2016 / Revised: 26 June 2016 / Accepted: 27 June 2016 / Published: 2 July 2016
Cited by 4 | PDF Full-text (4694 KB) | HTML Full-text | XML Full-text
Abstract
This paper investigates the characteristics of graphene oxide (GO) for Bisphenol A (BPA) adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time
[...] Read more.
This paper investigates the characteristics of graphene oxide (GO) for Bisphenol A (BPA) adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time and the initial BPA concentration, the increment of pH above 8, GO dosage, and temperature showed the reverse results. The thermodynamic study suggested that BPA adsorption on GO was an exothermic and spontaneous process. The kinetics was explained by the pseudo-second-order model which covers all steps of adsorption. The fit of the results with the Langmuir isotherm indicated the monolayer adsorption. At 298 K, the adsorption reached equilibrium within 30 min with the maximum adsorption capacity of 49.26 mg/g. The low BPA adsorption capacity of GO can be interpreted by the occurrence of oxygen-containing functional groups (OCFGs) that are able to form hydrogen bonds with the surrounding OCFGs and water molecules. This effect inhibited the role of π–π interactions that are mainly responsible for the adsorption of BPA. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessArticle Graphene FETs with Low-Resistance Hybrid Contacts for Improved High Frequency Performance
Nanomaterials 2016, 6(5), 86; doi:10.3390/nano6050086
Received: 16 February 2016 / Revised: 14 April 2016 / Accepted: 3 May 2016 / Published: 10 May 2016
Cited by 1 | PDF Full-text (4376 KB) | HTML Full-text | XML Full-text
Abstract
This work proposes a novel geometry field effect transistor with graphene as a channel—graphene field-effect transistor (GFET), having a hybrid contact that consists of an ohmic source/drain and its extended part towards the gate, which is capacitively coupled to the channel. The ohmic
[...] Read more.
This work proposes a novel geometry field effect transistor with graphene as a channel—graphene field-effect transistor (GFET), having a hybrid contact that consists of an ohmic source/drain and its extended part towards the gate, which is capacitively coupled to the channel. The ohmic contacts are used for direct current (DC) biasing, whereas their capacitive extension reduces access region length and provides the radio frequency (RF) signal a low impedance path. Minimization of the access region length, along with the paralleling of ohmic contact’s resistance and resistive part of capacitively coupled contact’s impedance, lower the overall source/drain resistance, which results in an increase in current gain cut-off frequency, fT. The DC and high-frequency characteristics of the two chosen conventional baseline GFETs, and their modified versions with proposed hybrid contacts, have been extensively studied, compared, and analyzed using numerical and analytical techniques. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Review

Jump to: Research

Open AccessReview Black Phosphorus: Critical Review and Potential for Water Splitting Photocatalyst
Nanomaterials 2016, 6(11), 194; doi:10.3390/nano6110194
Received: 31 August 2016 / Revised: 17 October 2016 / Accepted: 25 October 2016 / Published: 29 October 2016
Cited by 10 | PDF Full-text (3349 KB) | HTML Full-text | XML Full-text
Abstract
A century after its first synthesis in 1914, black phosphorus has been attracting significant attention as a promising two-dimensional material in recent years due to its unique properties. Nowadays, with the development of its exfoliation method, there are extensive applications of black phosphorus
[...] Read more.
A century after its first synthesis in 1914, black phosphorus has been attracting significant attention as a promising two-dimensional material in recent years due to its unique properties. Nowadays, with the development of its exfoliation method, there are extensive applications of black phosphorus in transistors, batteries and optoelectronics. Though, because of its hardship in mass production and stability problems, the potential of the black phosphorus in various fields is left unexplored. Here, we provide a comprehensive review of crystal structure, electronic, optical properties and synthesis of black phosphorus. Recent research works about the applications of black phosphorus is summarized. Among them, the possibility of black phosphorous as a solar water splitting photocatalyst is mainly discussed and the feasible novel structure of photocatalysts based on black phosphorous is proposed. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Open AccessReview Two-Dimensional Semiconductor Optoelectronics Based on van der Waals Heterostructures
Nanomaterials 2016, 6(11), 193; doi:10.3390/nano6110193
Received: 7 September 2016 / Revised: 17 October 2016 / Accepted: 18 October 2016 / Published: 27 October 2016
Cited by 3 | PDF Full-text (6104 KB) | HTML Full-text | XML Full-text
Abstract
Two-dimensional (2D) semiconductors such as transition metal dichalcogenides (TMDCs) and black phosphorous have drawn tremendous attention as an emerging optical material due to their unique and remarkable optical properties. In addition, the ability to create the atomically-controlled van der Waals (vdW) heterostructures enables
[...] Read more.
Two-dimensional (2D) semiconductors such as transition metal dichalcogenides (TMDCs) and black phosphorous have drawn tremendous attention as an emerging optical material due to their unique and remarkable optical properties. In addition, the ability to create the atomically-controlled van der Waals (vdW) heterostructures enables realizing novel optoelectronic devices that are distinct from conventional bulk counterparts. In this short review, we first present the atomic and electronic structures of 2D semiconducting TMDCs and their exceptional optical properties, and further discuss the fabrication and distinctive features of vdW heterostructures assembled from different kinds of 2D materials with various physical properties. We then focus on reviewing the recent progress on the fabrication of 2D semiconductor optoelectronic devices based on vdW heterostructures including photodetectors, solar cells, and light-emitting devices. Finally, we highlight the perspectives and challenges of optoelectronics based on 2D semiconductor heterostructures. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Graphene FETs with Low-Resistance Hybrid Contacts for Improved High Frequency Performance
Authors: Chowdhury Al-Amin 1,*, Mustafa Karabiyik 1, Phani Kiran Vabbina1, Raju Sinha 1, and Nezih Pala1 1
Abstract: This work proposes a novel geometry field effect transistor with graphene as channel— Graphene Field-Effect Transistor (GFET), having a hybrid contact that consists of ohmic Source/Drain and its extended part towards the Gate, which is capacitively coupled to the channel. The ohmic contacts are used for DC biasing whereas their capacitive extension reduces access region length and provides the high frequency RF signal a low impedance path. Minimization of access region length along with the paralleling of ohmic contact’s resistance and resistive part of capacitively coupled contact’s impedance lower the overall Source/Drain resistance, which results in an increases current gain cut-off frequency, fT. The DC and high-frequency characteristics of two chosen conventional baseline GFETs and their modified versions with proposed hybrid contacts have been extensively studied, compared, and analyzed using numerical and analytical techniques.

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