1
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Moehring NK, Naclerio AE, Chaturvedi P, Knight T, Kidambi PR. Ultra-thin proton conducting carrier layers for scalable integration of atomically thin 2D materials with proton exchange polymers for next-generation PEMs. NANOSCALE 2024; 16:6973-6983. [PMID: 38353333 DOI: 10.1039/d3nr05202h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Scalable approaches for synthesis and integration of proton selective atomically thin 2D materials with proton conducting polymers can enable next-generation proton exchange membranes (PEMs) with minimal crossover of reactants or undesired species while maintaining adequately high proton conductance for practical applications. Here, we systematically investigate facile and scalable approaches to interface monolayer graphene synthesized via scalable chemical vapor deposition (CVD) on Cu foil with the most widely used proton exchange polymer Nafion 211 (N211, ∼25 μm thick film) via (i) spin-coating a ∼700 nm thin Nafion carrier layer to transfer graphene (spin + scoop), (ii) casting a Nafion film and cold pressing (cold press), and (iii) hot pressing (hot press) while minimizing micron-scale defects to <0.3% area. Interfacing CVD graphene on Cu with N211 via cold press or hot press and subsequent removal of Cu via etching results in ∼50% lower areal proton conductance compared to membranes fabricated via the spin + scoop method. Notably, the areal proton conductance can be recovered by soaking the hot and cold press membranes in 0.1 M HCl, without significant damage to graphene. We rationalize our finding by the significantly smaller reservoir for cation uptake from Cu etching for the ∼700 nm thin carrier Nafion layer used for spin + scoop transfer compared to the ∼25 μm thick N211 film for hot and cold pressing. Finally, we demonstrate performance in H2 fuel cells with power densities of ∼0.23 W cm-2 and up to ∼41-54% reduction in H2 crossover for the N211|G|N211 sandwich membranes compared to the control N211|N211 indicating potential for our approach in enabling advanced PEMs for fuel cells, redox-flow batteries, isotope separations and beyond.
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Affiliation(s)
- Nicole K Moehring
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN 37235, USA.
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
| | - Andrew E Naclerio
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
| | - Pavan Chaturvedi
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
| | - Thomas Knight
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Piran R Kidambi
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN 37235, USA.
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
- Mechanical Engineering Department, Vanderbilt University, Nashville, TN, 37212, USA
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2
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Whelan PR, De Fazio D, Pasternak I, Thomsen JD, Zelzer S, Mikkelsen MO, Booth TJ, Diekhöner L, Sassi U, Johnstone D, Midgley PA, Strupinski W, Jepsen PU, Ferrari AC, Bøggild P. Mapping nanoscale carrier confinement in polycrystalline graphene by terahertz spectroscopy. Sci Rep 2024; 14:3163. [PMID: 38326379 PMCID: PMC10850153 DOI: 10.1038/s41598-024-51548-z] [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: 08/15/2023] [Accepted: 01/06/2024] [Indexed: 02/09/2024] Open
Abstract
Terahertz time-domain spectroscopy (THz-TDS) can be used to map spatial variations in electrical properties such as sheet conductivity, carrier density, and carrier mobility in graphene. Here, we consider wafer-scale graphene grown on germanium by chemical vapor deposition with non-uniformities and small domains due to reconstructions of the substrate during growth. The THz conductivity spectrum matches the predictions of the phenomenological Drude-Smith model for conductors with non-isotropic scattering caused by backscattering from boundaries and line defects. We compare the charge carrier mean free path determined by THz-TDS with the average defect distance assessed by Raman spectroscopy, and the grain boundary dimensions as determined by transmission electron microscopy. The results indicate that even small angle orientation variations below 5° within graphene grains influence the scattering behavior, consistent with significant backscattering contributions from grain boundaries.
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Affiliation(s)
- Patrick R Whelan
- DTU Physics, Technical University of Denmark, Fysikvej, Bld. 309, 2800, Kongens Lyngby, Denmark
- Department of Materials and Production, Aalborg University, Skjernvej 4A, 9220, Aalborg, Denmark
| | - Domenico De Fazio
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, 30172, Venice, Italy
| | - Iwona Pasternak
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
- Vigo System S.A., 129/133 Poznanska Str, 05-850, Ozarow Mazowiecki, Poland
| | - Joachim D Thomsen
- DTU Physics, Technical University of Denmark, Fysikvej, Bld. 309, 2800, Kongens Lyngby, Denmark
| | - Steffen Zelzer
- Department of Materials and Production, Aalborg University, Skjernvej 4A, 9220, Aalborg, Denmark
| | - Martin O Mikkelsen
- Department of Materials and Production, Aalborg University, Skjernvej 4A, 9220, Aalborg, Denmark
| | - Timothy J Booth
- DTU Physics, Technical University of Denmark, Fysikvej, Bld. 309, 2800, Kongens Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Technical University of Denmark, Ørsteds Plads 345C, 2800, Kongens Lyngby, Denmark
| | - Lars Diekhöner
- Department of Materials and Production, Aalborg University, Skjernvej 4A, 9220, Aalborg, Denmark
| | - Ugo Sassi
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Duncan Johnstone
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Paul A Midgley
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Wlodek Strupinski
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
- Vigo System S.A., 129/133 Poznanska Str, 05-850, Ozarow Mazowiecki, Poland
| | - Peter U Jepsen
- Center for Nanostructured Graphene (CNG), Technical University of Denmark, Ørsteds Plads 345C, 2800, Kongens Lyngby, Denmark
- DTU Fotonik, Technical University of Denmark, Ørsteds Plads 343, 2800, Kongens Lyngby, Denmark
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Peter Bøggild
- DTU Physics, Technical University of Denmark, Fysikvej, Bld. 309, 2800, Kongens Lyngby, Denmark.
- Center for Nanostructured Graphene (CNG), Technical University of Denmark, Ørsteds Plads 345C, 2800, Kongens Lyngby, Denmark.
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3
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Gumprich A, Liedtke J, Beck S, Chirca I, Potočnik T, Alexander-Webber JA, Hofmann S, Tappertzhofen S. Buried graphene heterostructures for electrostatic doping of low-dimensional materials. NANOTECHNOLOGY 2023; 34:265203. [PMID: 36758234 DOI: 10.1088/1361-6528/acbaa2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
The fabrication and characterization of steep slope transistor devices based on low-dimensional materials requires precise electrostatic doping profiles with steep spatial gradients in order to maintain maximum control over the channel. In this proof-of-concept study we present a versatile graphene heterostructure platform with three buried individually addressable gate electrodes. The platform is based on a vertical stack of embedded titanium and graphene separated by an intermediate oxide to provide an almost planar surface. We demonstrate the functionality and advantages of the platform by exploring transfer and output characteristics at different temperatures of carbon nanotube field-effect transistors with different electrostatic doping configurations. Furthermore, we back up the concept with finite element simulations to investigate the surface potential. The presented heterostructure is an ideal platform for analysis of electrostatic doping of low-dimensional materials for novel low-power transistor devices.
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Affiliation(s)
- A Gumprich
- Chair for Micro- and Nanoelectronics, Department of Electrical Engineering and Information Technology, TU Dortmund University, Martin-Schmeisser-Weg 4-6, D-44227, Dortmund, Germany
| | - J Liedtke
- Chair for Micro- and Nanoelectronics, Department of Electrical Engineering and Information Technology, TU Dortmund University, Martin-Schmeisser-Weg 4-6, D-44227, Dortmund, Germany
| | - S Beck
- Chair for Micro- and Nanoelectronics, Department of Electrical Engineering and Information Technology, TU Dortmund University, Martin-Schmeisser-Weg 4-6, D-44227, Dortmund, Germany
| | - I Chirca
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - T Potočnik
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - J A Alexander-Webber
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - S Hofmann
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - S Tappertzhofen
- Chair for Micro- and Nanoelectronics, Department of Electrical Engineering and Information Technology, TU Dortmund University, Martin-Schmeisser-Weg 4-6, D-44227, Dortmund, Germany
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4
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Tappertzhofen S, Braeuninger-Weimer P, Gumprich A, Chirca I, Potočnik T, Alexander-Webber JA, Hofmann S. Transfer-free graphene passivation of sub 100 nm thin Pt and Pt–Cu electrodes for memristive devices. SN APPLIED SCIENCES 2023. [DOI: 10.1007/s42452-023-05314-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
AbstractMemristive switches are among the most promising building blocks for future neuromorphic computing. These devices are based on a complex interplay of redox reactions on the nanoscale. Nanoionic phenomena enable non-linear and low-power resistance transition in ultra-short programming times. However, when not controlled, the same electrochemical reactions can result in device degradation and instability over time. Two-dimensional barriers have been suggested to precisely manipulate the nanoionic processes. But fabrication-friendly integration of these materials in memristive devices is challenging.Here we report on a novel process for graphene passivation of thin platinum and platinum/copper electrodes. We also studied the level of defects of graphene after deposition of selected oxides that are relevant for memristive switching.
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5
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Hung YH, Hsieh TC, Lu WC, Su CY. Ultraclean and Facile Patterning of CVD Graphene by a UV-Light-Assisted Dry Transfer Method. ACS APPLIED MATERIALS & INTERFACES 2023; 15:4826-4834. [PMID: 36646630 DOI: 10.1021/acsami.2c20076] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The synthesis of large-area graphene by the chemical vapor deposition (CVD) method is a mature technology; however, a transfer procedure is required to integrate CVD-grown graphene into a functional device. The reported methods for transferring graphene films cause different degrees of defects (cracking, rupture) and ion/polymer residues, which deteriorate or alter the electrical properties of as-grown graphene. Developing a reliable and fast transfer method that can maintain high-quality graphene remains a challenge. In this work, we employed UV light release tape (UV-RT) as the support layer to replace the frequently used thermal release tape (TRT) in a typical roll-to-roll dry transfer process. In this process, we used an easier-to-remove polymer as an adhesion layer to greatly reduce the strain and defects that occur during the transfer process. The cleanliness of graphene transferred by this method is above 99%, and the carrier mobility is 1.6 and 1.1 times higher than that obtained with conventional wet transfer and TRT transfer methods, respectively. UV illumination leads to facile and uniform release of the graphene film onto the target substrate, achieving one-step and selective patterning of graphene (feature size of <100 μm). The UV-assisted decomposition of the polymer molecular structure into small molecules enables a residue-free and ultraclean graphene surface. This proposed transfer method enables facile patterning of graphene and 2D films while maintaining high quality, which paves the way for versatile functional graphene applications.
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Affiliation(s)
- Yu-Han Hung
- Graduate Institute of Energy Engineering, National Central University, Tao-Yuan32001, Taiwan
- Department of Mechanical Engineering, National Central University, Tao-Yuan32001, Taiwan
| | - Tzu-Chiao Hsieh
- Graduate Institute of Energy Engineering, National Central University, Tao-Yuan32001, Taiwan
| | - Wan-Chui Lu
- Department of Mechanical Engineering, National Central University, Tao-Yuan32001, Taiwan
| | - Ching-Yuan Su
- Graduate Institute of Energy Engineering, National Central University, Tao-Yuan32001, Taiwan
- Department of Mechanical Engineering, National Central University, Tao-Yuan32001, Taiwan
- Graduate Institute of Material Science and Engineering, National Central University, Tao-Yuan32001, Taiwan
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6
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Burton OJ, Winter Z, Watanabe K, Taniguchi T, Beschoten B, Stampfer C, Hofmann S. Putting High-Index Cu on the Map for High-Yield, Dry-Transferred CVD Graphene. ACS NANO 2023; 17:1229-1238. [PMID: 36594782 PMCID: PMC9878973 DOI: 10.1021/acsnano.2c09253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Reliable, clean transfer and interfacing of 2D material layers are technologically as important as their growth. Bringing both together remains a challenge due to the vast, interconnected parameter space. We introduce a fast-screening descriptor approach to demonstrate holistic data-driven optimization across the entirety of process steps for the graphene-Cu model system. We map the crystallographic dependences of graphene chemical vapor deposition, interfacial Cu oxidation to decouple graphene, and its dry delamination across inverse pole figures. Their overlay enables us to identify hitherto unexplored (168) higher index Cu orientations as overall optimal orientations. We show the effective preparation of such Cu orientations via epitaxial close-space sublimation and achieve mechanical transfer with a very high yield (>95%) and quality of graphene domains, with room-temperature electron mobilities in the range of 40000 cm2/(V s). Our approach is readily adaptable to other descriptors and 2D material systems, and we discuss the opportunities of such a holistic optimization.
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Affiliation(s)
- Oliver J. Burton
- Department
of Engineering, University of Cambridge, CambridgeCB3 0FA, United Kingdom
| | - Zachary Winter
- 2nd
Institute of Physics A and JARA-FIT, RWTH
Aachen University, 52074Aachen, Germany
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki305-0044, Japan
| | - Bernd Beschoten
- 2nd
Institute of Physics A and JARA-FIT, RWTH
Aachen University, 52074Aachen, Germany
| | - Christoph Stampfer
- 2nd
Institute of Physics A and JARA-FIT, RWTH
Aachen University, 52074Aachen, Germany
- Peter
Grünberg Institute (PGI-9), Forschungszentrum
Jülich, 52425Jülich, Germany
| | - Stephan Hofmann
- Department
of Engineering, University of Cambridge, CambridgeCB3 0FA, United Kingdom
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7
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Cheng P, Espano J, Harkaway A, Naclerio AE, Moehring NK, Braeuninger-Weimer P, Kidambi PR. Nanoporous Atomically Thin Graphene Filters for Nanoscale Aerosols. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41328-41336. [PMID: 36036893 DOI: 10.1021/acsami.2c10827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Filtering nanoparticulate aerosols from air streams is important for a wide range of personal protection equipment (PPE), including masks used for medical research, healthcare, law enforcement, first responders, and military applications. Conventional PPEs capable of filtering nanoparticles <300 nm are typically bulky and sacrifice breathability to maximize protection from exposure to harmful nanoparticulate aerosols including viruses ∼20-300 nm from air streams. Here, we show that nanopores introduced into centimeter-scale monolayer graphene supported on polycarbonate track-etched supports via a facile oxygen plasma etch can allow for filtration of aerosolized SiO2 nanoparticles of ∼5-20 nm from air steams while maintaining air permeance of ∼2.28-7.1 × 10-5 mol m-2 s-1 Pa-1. Furthermore, a systematic increase in oxygen plasma etch time allows for a tunable size-selective filtration of aerosolized nanoparticles. We demonstrate a new route to realize ultra-compact, lightweight, and conformal form-factor filters capable of blocking sub-20 nm aerosolized nanoparticles with particular relevance for biological/viral threat mitigation.
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Affiliation(s)
- Peifu Cheng
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Jeremy Espano
- Interdisciplinary Graduate Program for Material Science, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Andrew Harkaway
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Andrew E Naclerio
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Nicole K Moehring
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Interdisciplinary Graduate Program for Material Science, Vanderbilt University, Nashville, Tennessee 37212, United States
| | | | - Piran R Kidambi
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Vanderbilt Institute of Nanoscale Sciences and Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
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8
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Zhang K, Ban C, Yuan Y, Huang L, Gan Y. Nanoscale imaging of oxidized copper foil covered with CVD‐grown graphene layers. SURF INTERFACE ANAL 2022. [DOI: 10.1002/sia.7096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kai Zhang
- School of Electronics and Information Engineering Hebei University of Technology Tianjin P. R. China
| | - Chun‐guang Ban
- School of Materials Science and Technology Hebei University of Technology Tianjin P. R. China
| | - Ye Yuan
- School of Materials Science and Technology Hebei University of Technology Tianjin P. R. China
| | - Li Huang
- School of Electronics and Information Engineering Hebei University of Technology Tianjin P. R. China
| | - Yang Gan
- School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin P. R. China
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin P. R. China
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9
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Sakamoto Y, Ikuta T, Maehashi K. Electrical Detection of Molecular Transformations Associated with Chemical Reactions Using Graphene Devices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:45001-45007. [PMID: 34494425 DOI: 10.1021/acsami.1c09985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This study proposes a method to electrically detect chemical reactions that involve bond changes through reactions on graphene surfaces. To achieve a highly sensitive detection, we focused on the thiol-ene reaction that combines the maleimide and thiol groups. Graphene field-effect transistors (FETs) were used to detect the binding changes of the modified molecules. Graphene has high carrier mobility and is sensitive to changes in the electronic state of its surface. Graphene has been used as a sensor to detect low-concentration targets with high sensitivity. N-(9-Acridinyl)maleimide (NAM) was chosen as the modified molecule to immobilize maleimide on graphene through π-interaction, and methanethiol (MeSH) was set as the target thiol. The modification of NAM to graphene was first confirmed by attenuated total reflection Fourier transform infrared spectroscopy, and the modification density was 0.5 ± 0.1/nm2 through cyclic voltammetry. Owing to a bond exchange, the transfer characteristics of the graphene FET shifted by 2 V to the negative direction after being exposed to MeSH at 10 parts per billion (ppb), equivalent to 0.2 ng, under ultraviolet irradiation. With 5000 ppb of acetic acid, it only shifted 0.7 V. With 1000 ppb of ethanol and 10,000 ppb of methanol, it shifted to the positive direction by 0.4 and 0.6 V, respectively. Because the nontarget molecule showed only a slight response, a thiol-ene chemical reaction was detected. The proposed method can detect the bond-change reaction using an ultralow concentration of MeSH, which indicates that at least 10 ppb (or 0.2 ng) of MeSH was detected by the graphene FET.
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Affiliation(s)
- Yuri Sakamoto
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Takashi Ikuta
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Kenzo Maehashi
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
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10
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Giambra M, Mišeikis V, Pezzini S, Marconi S, Montanaro A, Fabbri F, Sorianello V, Ferrari AC, Coletti C, Romagnoli M. Wafer-Scale Integration of Graphene-Based Photonic Devices. ACS NANO 2021; 15:3171-3187. [PMID: 33522789 PMCID: PMC7905876 DOI: 10.1021/acsnano.0c09758] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 05/13/2023]
Abstract
Graphene and related materials can lead to disruptive advances in next-generation photonics and optoelectronics. The challenge is to devise growth, transfer and fabrication protocols providing high (≥5000 cm2 V-1 s-1) mobility devices with reliable performance at the wafer scale. Here, we present a flow for the integration of graphene in photonics circuits. This relies on chemical vapor deposition (CVD) of single layer graphene (SLG) matrices comprising up to ∼12000 individual single crystals, grown to match the geometrical configuration of the devices in the photonic circuit. This is followed by a transfer approach which guarantees coverage over ∼80% of the device area, and integrity for up to 150 mm wafers, with room temperature mobility ∼5000 cm2 V-1 s-1. We use this process flow to demonstrate double SLG electro-absorption modulators with modulation efficiency ∼0.25, 0.45, 0.75, 1 dB V-1 for device lengths ∼30, 60, 90, 120 μm. The data rate is up to 20 Gbps. Encapsulation with single-layer hexagonal boron nitride (hBN) is used to protect SLG during plasma-enhanced CVD of Si3N4, ensuring reproducible device performance. The processes are compatible with full automation. This paves the way for large scale production of graphene-based photonic devices.
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Affiliation(s)
- Marco
A. Giambra
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vaidotas Mišeikis
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Sergio Pezzini
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Simone Marconi
- Photonic
Networks and Technologies Lab, Tecip Institute, Scuola Superiore Sant’Anna, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Alberto Montanaro
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Filippo Fabbri
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vito Sorianello
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Andrea C. Ferrari
- Cambridge
Graphene Centre, Cambridge University, 9 J.J. Thompson, Cambridge, U.K.
| | - Camilla Coletti
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Marco Romagnoli
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- CamGraPhiC, Via Moruzzi 1, 56124 Pisa, Italy
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11
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Cheng P, Moehring NK, Idrobo JC, Ivanov IN, Kidambi PR. Scalable synthesis of nanoporous atomically thin graphene membranes for dialysis and molecular separations via facile isopropanol-assisted hot lamination. NANOSCALE 2021; 13:2825-2837. [PMID: 33508042 DOI: 10.1039/d0nr07384a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Scalable graphene synthesis and facile large-area membrane fabrication are imperative to advance nanoporous atomically thin membranes (NATMs) for molecular separations. Although chemical vapor deposition (CVD) allows for roll-to-roll high-quality monolayer graphene synthesis, facile transfer with atomically clean interfaces to porous supports for large-area NATM fabrication remains extremely challenging. Sacrificial polymer scaffolds commonly used for graphene transfer typically leave polymer residues detrimental to membrane performance and transfers without polymer scaffolds suffer from low yield resulting in high non-selective leakage through NATMs. Here, we systematically study the factors influencing graphene NATM fabrication and report on a novel roll-to-roll manufacturing compatible isopropanol-assisted hot lamination (IHL) process that enables scalable, facile and clean transfer of CVD graphene on to polycarbonate track etched (PCTE) supports with coverage ≥99.2%, while preserving support integrity/porosity. We demonstrate fully functional centimeter-scale graphene NATMs that show record high permeances (∼2-3 orders of magnitude higher) and better selectivity than commercially available state-of-the-art polymeric dialysis membranes, specifically in the 0-1000 Da range. Our work highlights a scalable approach to fabricate graphene NATMs for practical applications and is fully compatible with roll-to-roll manufacturing processes.
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Affiliation(s)
- Peifu Cheng
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA.
| | - Nicole K Moehring
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA. and Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37212, USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Ilia N Ivanov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Piran R Kidambi
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA. and Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37212, USA and Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA
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12
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Tan J, Wang Y, Guo Y. Humidity effect on peeling of monolayer graphene and hexagonal boron nitride. NANOTECHNOLOGY 2021; 32:025302. [PMID: 33047676 DOI: 10.1088/1361-6528/abba97] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ambient humidity introduces water adsorption and intercalation at the surfaces and interfaces of low-dimensional materials. Our extensive molecular dynamics (MD) simulations reveal the completely opposite contributions of interfacial water to the peeling of monolayer graphene and hexagonal boron nitride (h-BN) sheets from graphite and BN substrates. For graphene, interfacial water decreases the peeling force, due to lower adhesion at the graphene/water interface. The peeling force of h-BN increases with an increase in the thickness of interfacial water, owing to stronger adhesion at the h-BN/water interface and the detachment of the water layer from the substrates. In this work, a theoretical model considering graphene/water and water/substrate interfacial adhesion energies is established, to predict the peeling forces of graphene and h-BN, which coincides well with the peeling forces predicted by the MD simulations. Our results should provide a deeper insight into the effect of interfacial water, induced by ambient humidity, on mechanical exfoliation and the transfer of two-dimensional van der Waals crystals.
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Affiliation(s)
- Jie Tan
- State Key Laboratory of Mechanics and Control of Mechanical Structures and MOE Key Laboratory for Intelligent Nano Materials and Devices, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
| | - Yue Wang
- State Key Laboratory of Mechanics and Control of Mechanical Structures and MOE Key Laboratory for Intelligent Nano Materials and Devices, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
| | - Yufeng Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structures and MOE Key Laboratory for Intelligent Nano Materials and Devices, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
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13
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Braeuninger-Weimer P, Burton OJ, Zeller P, Amati M, Gregoratti L, Weatherup RS, Hofmann S. Crystal Orientation Dependent Oxidation Modes at the Buried Graphene-Cu Interface. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2020; 32:7766-7776. [PMID: 32982043 PMCID: PMC7513576 DOI: 10.1021/acs.chemmater.0c02296] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/25/2020] [Indexed: 06/11/2023]
Abstract
We combine spatially resolved scanning photoelectron spectroscopy with confocal Raman and optical microscopy to reveal how the oxidation of the buried graphene-Cu interface relates to the Cu crystallographic orientation. We analyze over 100 different graphene covered Cu (high and low index) orientations exposed to air for 2 years. Four general oxidation modes are observed that can be mapped as regions onto the polar plot of Cu surface orientations. These modes are (1) complete, (2) irregular, (3) inhibited, and (4) enhanced wrinkle interface oxidation. We present a comprehensive characterization of these modes, consider the underlying mechanisms, compare air and water mediated oxidation, and discuss this in the context of the diverse prior literature in this area. This understanding incorporates effects from across the wide parameter space of 2D material interface engineering, relevant to key challenges in their emerging applications, ranging from scalable transfer to electronic contacts, encapsulation, and corrosion protection.
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Affiliation(s)
| | - Oliver J. Burton
- Department
of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Patrick Zeller
- Elettra-Sincrotrone
Trieste S.C.p.A., AREA Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Matteo Amati
- Elettra-Sincrotrone
Trieste S.C.p.A., AREA Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Luca Gregoratti
- Elettra-Sincrotrone
Trieste S.C.p.A., AREA Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Robert S. Weatherup
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United
Kingdom
| | - Stephan Hofmann
- Department
of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
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14
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Luo B, Koleini M, Whelan PR, Shivayogimath A, Brandbyge M, Bøggild P, Booth TJ. Graphene-Subgrain-Defined Oxidation of Copper. ACS APPLIED MATERIALS & INTERFACES 2019; 11:48518-48524. [PMID: 31797664 DOI: 10.1021/acsami.9b15931] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The correlation between the crystal structure of chemical vapor deposition (CVD)-grown graphene and the crystal structure of the Cu growth substrate and their mutual effect on the oxidation of the underlying Cu are systematically explored. We report that natural oxygen or water intercalation along the graphene-Cu interface results in an orientation-dependent oxidation rate of the Cu surface, particularly noticeable for bicrystal graphene domains on the same copper grain, suggesting that the relative crystal orientation of subgrains determines the degree of Cu oxidation. Atomistic force field calculations support these observations, showing that graphene domains have preferential alignment with the Cu(111) with a smaller average height above the global Cu surface as compared to intermediate orientations, and that this is the origin of the heterogeneous oxidation rate of Cu. This work demonstrates that the natural oxidation resistance of Cu coated by graphene is highly dependent on the crystal orientation and lattice alignment of Cu and graphene, which is key information for engineering the interface configuration of the graphene-Cu system for specific functionalities in mechanical, anticorrosion, and electrical applications of CVD-grown graphene.
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Affiliation(s)
- Birong Luo
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
- College of Physics and Materials Science, Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials , Tianjin Normal University , 300387 Tianjin , P. R. China
| | - Mohammad Koleini
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
| | - Patrick R Whelan
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
- Center for Nanostructured Graphene (CNG) , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | - Abhay Shivayogimath
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
- Center for Nanostructured Graphene (CNG) , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | - Mads Brandbyge
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
| | - Peter Bøggild
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
- Center for Nanostructured Graphene (CNG) , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | - Timothy J Booth
- DTU Physics , Technical University of Denmark , Ørsteds Plads, 345C , 2800 Kgs. Lyngby , Denmark
- Center for Nanostructured Graphene (CNG) , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
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15
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De Fazio D, Purdie DG, Ott AK, Braeuninger-Weimer P, Khodkov T, Goossens S, Taniguchi T, Watanabe K, Livreri P, Koppens FHL, Hofmann S, Goykhman I, Ferrari AC, Lombardo A. High-Mobility, Wet-Transferred Graphene Grown by Chemical Vapor Deposition. ACS NANO 2019; 13:8926-8935. [PMID: 31322332 DOI: 10.1021/acsnano.9b02621] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report high room-temperature mobility in single-layer graphene grown by chemical vapor deposition (CVD) after wet transfer on SiO2 and hexagonal boron nitride (hBN) encapsulation. By removing contaminations, trapped at the interfaces between single-crystal graphene and hBN, we achieve mobilities up to ∼70000 cm2 V-1 s-1 at room temperature and ∼120 000 cm2 V-1 s-1 at 9K. These are more than twice those of previous wet-transferred graphene and comparable to samples prepared by dry transfer. We also investigate the combined approach of thermal annealing and encapsulation in polycrystalline graphene, achieving room-temperature mobilities of ∼30 000 cm2 V-1 s-1. These results show that, with appropriate encapsulation and cleaning, room-temperature mobilities well above 10 000 cm2 V-1 s-1 can be obtained in samples grown by CVD and transferred using a conventional, easily scalable PMMA-based wet approach.
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Affiliation(s)
- Domenico De Fazio
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
| | - David G Purdie
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
| | - Anna K Ott
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
| | | | - Timofiy Khodkov
- ICFO-Institut de Ciencies Fotoniques , The Barcelona Institute of Science and Technology, 08860 Castelldefels ( Barcelona ), Spain
| | - Stijn Goossens
- ICFO-Institut de Ciencies Fotoniques , The Barcelona Institute of Science and Technology, 08860 Castelldefels ( Barcelona ), Spain
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | | | - Frank H L Koppens
- ICFO-Institut de Ciencies Fotoniques , The Barcelona Institute of Science and Technology, 08860 Castelldefels ( Barcelona ), Spain
| | - Stephan Hofmann
- Department of Engineering , University of Cambridge , Cambridge CB3 0FA , U.K
| | - Ilya Goykhman
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
| | - Andrea C Ferrari
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
| | - Antonio Lombardo
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 0FA , U.K
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16
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Wang R, Purdie DG, Fan Y, Massabuau FCP, Braeuninger-Weimer P, Burton OJ, Blume R, Schloegl R, Lombardo A, Weatherup RS, Hofmann S. A Peeling Approach for Integrated Manufacturing of Large Monolayer h-BN Crystals. ACS NANO 2019; 13:2114-2126. [PMID: 30642169 DOI: 10.1021/acsnano.8b08712] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hexagonal boron nitride (h-BN) is the only known material aside from graphite with a structure composed of simple, stable, noncorrugated atomically thin layers. While historically used as a lubricant in powder form, h-BN layers have become particularly attractive as an ultimately thin insulator, barrier, or encapsulant. Practically all emerging electronic and photonic device concepts currently rely on h-BN exfoliated from small bulk crystallites, which limits device dimensions and process scalability. We here focus on a systematic understanding of Pt-catalyzed h-BN crystal formation, in order to address this integration challenge for monolayer h-BN via an integrated chemical vapor deposition (CVD) process that enables h-BN crystal domain sizes exceeding 0.5 mm and a merged, continuous layer in a growth time of less than 45 min. The process makes use of commercial, reusable Pt foils and allows a delamination process for easy and clean h-BN layer transfer. We demonstrate sequential pick-up for the assembly of graphene/h-BN heterostructures with atomic layer precision, while minimizing interfacial contamination. The approach can be readily combined with other layered materials and enables the integration of CVD h-BN into high-quality, reliable 2D material device layer stacks.
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Affiliation(s)
- Ruizhi Wang
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - David G Purdie
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
- Cambridge Graphene Centre , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Ye Fan
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Fabien C-P Massabuau
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FA , United Kingdom
| | - Philipp Braeuninger-Weimer
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Oliver J Burton
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Raoul Blume
- Helmholtz-Zentrum Berlin für Materialen und Energie , D-12489 Berlin , Germany
| | | | - Antonio Lombardo
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
- Cambridge Graphene Centre , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Robert S Weatherup
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
- University of Manchester at Harwell, Diamond Light Source , Didcot , Oxfordshire OX11 0DE , U.K
| | - Stephan Hofmann
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
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17
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Braeuninger-Weimer P, Funke S, Wang R, Thiesen P, Tasche D, Viöl W, Hofmann S. Fast, Noncontact, Wafer-Scale, Atomic Layer Resolved Imaging of Two-Dimensional Materials by Ellipsometric Contrast Micrography. ACS NANO 2018; 12:8555-8563. [PMID: 30080966 DOI: 10.1021/acsnano.8b04167] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Adequate characterization and quality control of atomically thin layered materials (2DM) has become a serious challenge particularly given the rapid advancements in their large area manufacturing and numerous emerging industrial applications with different substrate requirements. Here, we focus on ellipsometric contrast micrography (ECM), a fast intensity mode within spectroscopic imaging ellipsometry, and show that it can be effectively used for noncontact, large area characterization of 2DM to map coverage, layer number, defects and contamination. We demonstrate atomic layer resolved, quantitative mapping of chemical vapor deposited graphene layers on Si/SiO2-wafers, but also on rough Cu catalyst foils, highlighting that ECM is applicable to all application relevant substrates. We discuss the optimization of ECM parameters for high throughput characterization. While the lateral resolution can be less than 1 μm, we particularly explore fast scanning and demonstrate imaging of a 4″ graphene wafer in 47 min at 10 μm lateral resolution, i.e., an imaging speed of 1.7 cm2/min. Furthermore, we show ECM of monolayer hexagonal BN (h-BN) and of h-BN/graphene bilayers, highlighting that ECM is applicable to a wide range of 2D layered structures that have previously been very challenging to characterize and thereby fills an important gap in 2DM metrology.
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Affiliation(s)
| | - Sebastian Funke
- Accurion GmbH , Stresemannstraße 30 , Göttingen 37079 , Germany
| | - Ruizhi Wang
- Department of Engineering , University of Cambridge , Cambridge CB3 0FA , United Kingdom
| | - Peter Thiesen
- Accurion GmbH , Stresemannstraße 30 , Göttingen 37079 , Germany
| | - Daniel Tasche
- Faculty of Natural Sciences and Technology , University of Applied Sciences and Arts , Von-Ossietzky-Straße 99 , Göttingen 37085 , Germany
| | - Wolfgang Viöl
- Faculty of Natural Sciences and Technology , University of Applied Sciences and Arts , Von-Ossietzky-Straße 99 , Göttingen 37085 , Germany
| | - Stephan Hofmann
- Department of Engineering , University of Cambridge , Cambridge CB3 0FA , United Kingdom
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18
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Whelan PR, Huang D, Mackenzie D, Messina SA, Li Z, Li X, Li Y, Booth TJ, Jepsen PU, Shi H, Bøggild P. Conductivity mapping of graphene on polymeric films by terahertz time-domain spectroscopy. OPTICS EXPRESS 2018; 26:17748-17754. [PMID: 30114060 DOI: 10.1364/oe.26.017748] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/21/2018] [Indexed: 06/08/2023]
Abstract
Fast inline characterization of the electrical properties of graphene on polymeric substrates is an essential requirement for quality control in industrial graphene production. Here we show that it is possible to measure the sheet conductivity of graphene on polymer films by terahertz time-domain spectroscopy (THz-TDS) when all internally reflected echoes in the substrate are taken into consideration. The conductivity measured by THz-TDS is comparable to values obtained from four point probe measurements. THz-TDS maps of 25x30 cm2 area graphene films were recorded and the DC conductivity and carrier scattering time were extracted from the measurements. Additionally, the THz-TDS conductivity maps highlight tears and holes in the graphene film, which are not easily visible by optical inspection.
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19
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Wei Q, Chen J, Ding P, Shen B, Yin J, Xu F, Xia Y, Liu Z. Synthesis of Easily Transferred 2D Layered BiI 3 Nanoplates for Flexible Visible-Light Photodetectors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:21527-21533. [PMID: 29847912 DOI: 10.1021/acsami.8b02582] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bismuth triiodide, BiI3, is one of the promising 2D layered materials from the family of metal halides. The unique electronic structure and properties make it an attractive material for the room-temperature gamma/X-ray detectors, high-efficiency photovoltaic absorbers, and Bi-based organic-inorganic hybrid perovskites. Other possibilities including optoelectronic devices and optical circuits are envisioned but rarely experimentally confirmed yet. Here, we report the synthesis of vertical 2D BiI3 nanoplates using the physical vapor deposition mechanism. The obtained products were found easy to be separated and transferred to other substrates. Photodetectors employing such 2D nanoplates on polyethylene terephthalate substrate are demonstrated to be quite sensitive to red light (635 nm) with good responsivity (2.8 A W-1), fast stable photoresponse (3/9 ms for raise/decay times), and remarkable specific detectivity (1.2 × 1012 jones), which attest to high comparability of the assembled components with many latest 2D nanostructured light sensors. In addition, such photodetectors exhibit outstanding mechanical stability and durability under different bending strains within the theoretically affordable levels, suggesting a variety of potential applications of 2D BiI3 for flexible devices.
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20
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Abstract
The pace of two-dimensional materials (2DM) research has been greatly accelerated by the ability to identify exfoliated thicknesses down to a monolayer from their optical contrast. Since this process requires time-consuming and error-prone manual assignment to avoid false-positives from image features with similar contrast, efforts towards fast and reliable automated assignments schemes is essential. We show that by modelling the expected 2DM contrast in digitally captured images, we can automatically identify candidate regions of 2DM. More importantly, we show a computationally-light machine vision strategy for eliminating false-positives from this set of 2DM candidates through the combined use of binary thresholding, opening and closing filters, and shape-analysis from edge detection. Calculation of data pyramids for arbitrarily high-resolution optical coverage maps of two-dimensional materials produced in this way allows the real-time presentation and processing of this image data in a zoomable interface, enabling large datasets to be explored and analysed with ease. The result is that a standard optical microscope with CCD camera can be used as an analysis tool able to accurately determine the coverage, residue/contamination concentration, and layer number for a wide range of presented 2DMs.
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21
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Cabrero-Vilatela A, Alexander-Webber JA, Sagade AA, Aria AI, Braeuninger-Weimer P, Martin MB, Weatherup RS, Hofmann S. Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer. NANOTECHNOLOGY 2017; 28:485201. [PMID: 29039352 DOI: 10.1088/1361-6528/aa940c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The transfer of chemical vapour deposited graphene from its parent growth catalyst has become a bottleneck for many of its emerging applications. The sacrificial polymer layers that are typically deposited onto graphene for mechanical support during transfer are challenging to remove completely and hence leave graphene and subsequent device interfaces contaminated. Here, we report on the use of atomic layer deposited (ALD) oxide films as protective interface and support layers during graphene transfer. The method avoids any direct contact of the graphene with polymers and through the use of thicker ALD layers (≥100 nm), polymers can be eliminated from the transfer-process altogether. The ALD film can be kept as a functional device layer, facilitating integrated device manufacturing. We demonstrate back-gated field effect devices based on single-layer graphene transferred with a protective Al2O3 film onto SiO2 that show significantly reduced charge trap and residual carrier densities. We critically discuss the advantages and challenges of processing graphene/ALD bilayer structures.
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Affiliation(s)
- A Cabrero-Vilatela
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
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22
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Caneva S, Martin MB, D'Arsié L, Aria AI, Sezen H, Amati M, Gregoratti L, Sugime H, Esconjauregui S, Robertson J, Hofmann S, Weatherup RS. From Growth Surface to Device Interface: Preserving Metallic Fe under Monolayer Hexagonal Boron Nitride. ACS APPLIED MATERIALS & INTERFACES 2017; 9:29973-29981. [PMID: 28782356 DOI: 10.1021/acsami.7b08717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigate the interfacial chemistry between Fe catalyst foils and monolayer hexagonal boron nitride (h-BN) following chemical vapor deposition and during subsequent atmospheric exposure, using scanning electron microscopy, X-ray photoemission spectroscopy, and scanning photoelectron microscopy. We show that regions of the Fe surface covered by h-BN remain in a metallic state during exposure to moist air for ∼40 h at room temperature. This protection is attributed to the strong interfacial interaction between h-BN and Fe, which prevents the rapid intercalation of oxidizing species. Local Fe oxidation is observed on bare Fe regions and close to defects in the h-BN film (e.g., domain boundaries, wrinkles, and edges), which over the longer-term provide pathways for slow bulk oxidation of Fe. We further confirm that the interface between h-BN and metallic Fe can be recovered by vacuum annealing at ∼600 °C, although this is accompanied by the creation of defects within the h-BN film. We discuss the importance of these findings in the context of integrated manufacturing and transfer-free device integration of h-BN, particularly for technologically important applications where h-BN has potential as a tunnel barrier such as magnetic tunnel junctions.
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Affiliation(s)
- Sabina Caneva
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Marie-Blandine Martin
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Lorenzo D'Arsié
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Adrianus I Aria
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
- Surface Engineering and Nanotechnology Institute, Cranfield University , College Road, MK43 0AL Cranfield, U.K
| | - Hikmet Sezen
- Elettra-Sincrotrone Trieste S.C.p.A., AREA Science Park , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Matteo Amati
- Elettra-Sincrotrone Trieste S.C.p.A., AREA Science Park , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Luca Gregoratti
- Elettra-Sincrotrone Trieste S.C.p.A., AREA Science Park , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Hisashi Sugime
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Santiago Esconjauregui
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - John Robertson
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Robert S Weatherup
- Department of Engineering, University of Cambridge , JJ Thomson Avenue, CB3 0FA Cambridge, U.K
- Materials Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
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23
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Lin H, Braeuninger-Weimer P, Kamboj VS, Jessop DS, Degl'Innocenti R, Beere HE, Ritchie DA, Zeitler JA, Hofmann S. Contactless graphene conductivity mapping on a wide range of substrates with terahertz time-domain reflection spectroscopy. Sci Rep 2017; 7:10625. [PMID: 28878213 PMCID: PMC5587735 DOI: 10.1038/s41598-017-09809-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/07/2017] [Indexed: 11/09/2022] Open
Abstract
We demonstrate how terahertz time-domain spectroscopy (THz-TDS) operating in reflection geometry can be used for quantitative conductivity mapping of large area chemical vapour deposited graphene films on sapphire, silicon dioxide/silicon and germanium. We validate the technique against measurements performed with previously established conventional transmission based THz-TDS and are able to resolve conductivity changes in response to induced back-gate voltages. Compared to the transmission geometry, measurement in reflection mode requires careful alignment and complex analysis, but circumvents the need of a terahertz transparent substrate, potentially enabling fast, contactless, in-line characterisation of graphene films on non-insulating substrates such as germanium.
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Affiliation(s)
- Hungyen Lin
- Department of Engineering, Lancaster University, Lancaster, LA1 4YW, United Kingdom.
| | - Philipp Braeuninger-Weimer
- Department of Engineering, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0FA, United Kingdom.
| | - Varun S Kamboj
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - David S Jessop
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Riccardo Degl'Innocenti
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Harvey E Beere
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - David A Ritchie
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - J Axel Zeitler
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, United Kingdom
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0FA, United Kingdom
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