1
|
Nwosu CN, Iliut M, Vijayaraghavan A. Graphene and water-based elastomer nanocomposites - a review. NANOSCALE 2021; 13:9505-9540. [PMID: 34037053 DOI: 10.1039/d1nr01324f] [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
Water-based elastomers (WBEs) are polymeric elastomers in aqueous systems. WBEs have recently continued to gain wide acceptability by both academia and industry due to their remarkable environmental and occupational safety friendly nature, as a non-toxic elastomeric dispersion with low-to-zero volatile organic compound (VOC) emission. However, their inherent poor mechanical and thermal properties remain a drawback to these sets of elastomers. Hence, nano-fillers such as graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelets (GNPs) are being employed for the reinforcement and enhancement of this set of elastomers. This work is geared towards a critical review and summation of the state-of-the-art developments of graphene enhanced water-based elastomer composites (G-WBEC), including graphene and composite production processes, properties, characterisation techniques and potential commercial applications. The dominant production techniques, such as emulsion mixing and in situ polymerisation processes, which include Pickering emulsion, mini-emulsion and micro-emulsion, as well as ball-milling approach, are systematically evaluated. Details of the account of mechanical properties, electrical conductivity, thermal stability and thermal conductivity enhancements, as well as multifunctional properties of G-WBEC are discussed, with further elaboration on the structure-property relationship effects (such as dispersion and filler-matrix interface) through effective and non-destructive characterisation tools like Raman and XRD, among others. The paper also evaluates details of the current application attempts and potential commercial opportunities for G-WBEC utilisation in aerospace, automotive, oil and gas, biomedicals, textiles, sensors, electronics, solar energy, and thermal management.
Collapse
Affiliation(s)
- Christian N Nwosu
- Department of Materials, The University of Manchester, Manchester M13 9PL, UK.
| | | | | |
Collapse
|
2
|
Berweger S, Zhang H, Sahoo PK, Kupp BM, Blackburn JL, Miller EM, Wallis TM, Voronine DV, Kabos P, Nanayakkara SU. Spatially Resolved Persistent Photoconductivity in MoS 2-WS 2 Lateral Heterostructures. ACS NANO 2020; 14:14080-14090. [PMID: 33044054 DOI: 10.1021/acsnano.0c06745] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The optical and electronic properties of 2D semiconductors are intrinsically linked via the strong interactions between optically excited bound species and free carriers. Here we use near-field scanning microwave microscopy (SMM) to image spatial variations in photoconductivity in MoS2-WS2 lateral multijunction heterostructures using photon energy-resolved narrowband illumination. We find that the onset of photoconductivity in individual domains corresponds to the optical absorption onset, confirming that the tightly bound excitons in transition metal dichalcogenides can nonetheless dissociate into free carriers. These photogenerated carriers are most likely n-type and are seen to persist for up to days. Informed by finite element modeling we reveal that they can increase the carrier density by up to 200 times. This persistent photoconductivity appears to be dominated by contributions from the multilayer MoS2 domains, and we attribute the flake-wide response in part to charge transfer across the heterointerface. Spatial correlation of our SMM imaging with photoluminescence (PL) mapping confirms the strong link between PL peak emission photon energy, PL intensity, and the local accumulated charge. This work reveals the spatially and temporally complex optoelectronic response of these systems and cautions that properties measured during or after illumination may not reflect the true dark state of these materials but rather a metastable charged state.
Collapse
Affiliation(s)
- Samuel Berweger
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Hanyu Zhang
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Prasana K Sahoo
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
- Materials Science Centre, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Benjamin M Kupp
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
- The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jeffrey L Blackburn
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Elisa M Miller
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Thomas M Wallis
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Dmitri V Voronine
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Pavel Kabos
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Sanjini U Nanayakkara
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| |
Collapse
|
3
|
Basak P, Ghosh P. Poly (methyl methacrylate)-graphene oxide supported palladium catalyst: A ligand free protocol for Suzuki and Heck coupling reaction in water medium. SYNTHETIC COMMUN 2018. [DOI: 10.1080/00397911.2018.1515365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Puja Basak
- Department of Chemistry, University of North Bengal, Darjeeling, West Bengal, India
| | - Pranab Ghosh
- Department of Chemistry, University of North Bengal, Darjeeling, West Bengal, India
| |
Collapse
|
4
|
Johnston SR, Ma EY, Shen ZX. Optically coupled methods for microwave impedance microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:043703. [PMID: 29716321 DOI: 10.1063/1.5011391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Scanning Microwave Impedance Microscopy (MIM) measurement of photoconductivity with 50 nm resolution is demonstrated using a modulated optical source. The use of a modulated source allows for the measurement of photoconductivity in a single scan without a reference region on the sample, as well as removing most topographical artifacts and enhancing signal to noise as compared with unmodulated measurement. A broadband light source with a tunable monochrometer is then used to measure energy resolved photoconductivity with the same methodology. Finally, a pulsed optical source is used to measure local photo-carrier lifetimes via MIM, using the same 50 nm resolution tip.
Collapse
Affiliation(s)
- Scott R Johnston
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Eric Yue Ma
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Zhi-Xun Shen
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| |
Collapse
|
5
|
Biagi MC, Badino G, Fabregas R, Gramse G, Fumagalli L, Gomila G. Direct mapping of the electric permittivity of heterogeneous non-planar thin films at gigahertz frequencies by scanning microwave microscopy. Phys Chem Chem Phys 2018; 19:3884-3893. [PMID: 28106185 DOI: 10.1039/c6cp08215g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We obtained maps of electric permittivity at ∼19 GHz frequencies on non-planar thin film heterogeneous samples by means of combined atomic force-scanning microwave microscopy (AFM-SMM). We show that the electric permittivity maps can be obtained directly from the capacitance images acquired in contact mode, after removing the topographic cross-talk effects. This result demonstrates the possibility of identifying the electric permittivity of different materials in a thin film sample irrespectively of their thickness by just direct imaging and processing. We show, in addition, that quantitative maps of the electric permittivity can be obtained with no need for any theoretical calculation or complex quantification procedures when the electric permittivity of one of the materials is known. To achieve these results the use of contact mode imaging is a key factor. For non-contact imaging modes the effects of local sample thickness and of the imaging distance make the interpretation of the capacitance images in terms of the electric permittivity properties of the materials much more complex. The present results represent a substantial contribution to the field of nanoscale microwave dielectric characterization of thin film materials with important implications for the characterization of novel 3D electronic devices and 3D nanomaterials.
Collapse
Affiliation(s)
- Maria Chiara Biagi
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain.
| | - Giorgio Badino
- Keysight Technologies Austria GmbH, Keysight Lab, Gruberst. 40, 4020-Linz, Austria
| | - Rene Fabregas
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeries: Electrònica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain
| | - Georg Gramse
- Johannes Kepler University Linz, Institute for Biophysics, Gruberst. 40, 4020-Linz, Austria
| | - Laura Fumagalli
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeries: Electrònica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain
| |
Collapse
|
6
|
Gu S, Zhou X, Lin T, Happy H, Lasri T. Broadband non-contact characterization of epitaxial graphene by near-field microwave microscopy. NANOTECHNOLOGY 2017; 28:335702. [PMID: 28726682 DOI: 10.1088/1361-6528/aa7a36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper, a broadband non-destructive and non-contact local characterization of graphene fabricated by epitaxial method on silicon carbide is demonstrated by using an interferometer-based near-field microwave microscope. First, a method has been proposed to extract the dielectric properties of silicon carbide, and finally, the graphene flake has been characterized as a resistance (∼20 kΩ) and a small inductance (360 pH) in the frequency band (2-18 GHz). The advantage of the proposed method is that there is no need to fabricate electrodes on the sample surface for the characterization. The instrument proposed is a good candidate for the local characterization of 2D materials.
Collapse
Affiliation(s)
- Sijia Gu
- Univ.Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520-IEMN, F-59000 Lille, France
| | | | | | | | | |
Collapse
|
7
|
Gramse G, Kölker A, Lim T, Stock TJZ, Solanki H, Schofield SR, Brinciotti E, Aeppli G, Kienberger F, Curson NJ. Nondestructive imaging of atomically thin nanostructures buried in silicon. SCIENCE ADVANCES 2017; 3:e1602586. [PMID: 28782006 PMCID: PMC5489266 DOI: 10.1126/sciadv.1602586] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 05/01/2017] [Indexed: 05/05/2023]
Abstract
It is now possible to create atomically thin regions of dopant atoms in silicon patterned with lateral dimensions ranging from the atomic scale (angstroms) to micrometers. These structures are building blocks of quantum devices for physics research and they are likely also to serve as key components of devices for next-generation classical and quantum information processing. Until now, the characteristics of buried dopant nanostructures could only be inferred from destructive techniques and/or the performance of the final electronic device; this severely limits engineering and manufacture of real-world devices based on atomic-scale lithography. Here, we use scanning microwave microscopy (SMM) to image and electronically characterize three-dimensional phosphorus nanostructures fabricated via scanning tunneling microscope-based lithography. The SMM measurements, which are completely nondestructive and sensitive to as few as 1900 to 4200 densely packed P atoms 4 to 15 nm below a silicon surface, yield electrical and geometric properties in agreement with those obtained from electrical transport and secondary ion mass spectroscopy for unpatterned phosphorus δ layers containing ~1013 P atoms. The imaging resolution was 37 ± 1 nm in lateral and 4 ± 1 nm in vertical directions, both values depending on SMM tip size and depth of dopant layers. In addition, finite element modeling indicates that resolution can be substantially improved using further optimized tips and microwave gradient detection. Our results on three-dimensional dopant structures reveal reduced carrier mobility for shallow dopant layers and suggest that SMM could aid the development of fabrication processes for surface code quantum computers.
Collapse
Affiliation(s)
- Georg Gramse
- Johannes Kepler University, Biophysics Institute, Gruberstrasse 40, 4020 Linz, Austria
- Corresponding author. (G.G.); (N.J.C.)
| | - Alexander Kölker
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
- Department of Electronic and Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
| | - Tingbin Lim
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
| | - Taylor J. Z. Stock
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
| | - Hari Solanki
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
| | - Steven R. Schofield
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
- Department of Physics and Astronomy, UCL, Gower Street, London WC1E 6BT, UK
| | - Enrico Brinciotti
- Keysight Laboratories, Keysight Technologies Inc., Gruberstrasse 40, 4020 Linz, Austria
| | - Gabriel Aeppli
- Department of Physics, ETH, Zurich CH-8093, Switzerland
- Institut de Physique, École polytechnique fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Paul Scherrer Institut, Villigen CH-5232, Switzerland
- Bio Nano Consulting, Gridiron Building, One Pancras Square, London N1C 4AG, UK
| | - Ferry Kienberger
- Keysight Laboratories, Keysight Technologies Inc., Gruberstrasse 40, 4020 Linz, Austria
| | - Neil J. Curson
- London Centre of Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH, UK
- Department of Electronic and Electrical Engineering, UCL, Torrington Place, London WC1E 7JE, UK
- Corresponding author. (G.G.); (N.J.C.)
| |
Collapse
|
8
|
Zalden P, Shu MJ, Chen F, Wu X, Zhu Y, Wen H, Johnston S, Shen ZX, Landreman P, Brongersma M, Fong SW, Wong HSP, Sher MJ, Jost P, Kaes M, Salinga M, von Hoegen A, Wuttig M, Lindenberg AM. Picosecond Electric-Field-Induced Threshold Switching in Phase-Change Materials. PHYSICAL REVIEW LETTERS 2016; 117:067601. [PMID: 27541475 DOI: 10.1103/physrevlett.117.067601] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 06/06/2023]
Abstract
Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag_{4}In_{3}Sb_{67}Te_{26}. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on subpicosecond time scales-faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.
Collapse
Affiliation(s)
- Peter Zalden
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Michael J Shu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Frank Chen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Xiaoxi Wu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Yi Zhu
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Scott Johnston
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Zhi-Xun Shen
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Patrick Landreman
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Mark Brongersma
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Scott W Fong
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - H-S Philip Wong
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - Meng-Ju Sher
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Peter Jost
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen, Germany
| | - Matthias Kaes
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen, Germany
| | - Martin Salinga
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen, Germany
| | | | - Matthias Wuttig
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen, Germany
- JARA - Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen, Germany
| | - Aaron M Lindenberg
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| |
Collapse
|
9
|
Seabron E, MacLaren S, Xie X, Rotkin SV, Rogers JA, Wilson WL. Scanning Probe Microwave Reflectivity of Aligned Single-Walled Carbon Nanotubes: Imaging of Electronic Structure and Quantum Behavior at the Nanoscale. ACS NANO 2016; 10:360-368. [PMID: 26688374 DOI: 10.1021/acsnano.5b04975] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Single-walled carbon nanotubes (SWNTs) are 1-dimensional nanomaterials with unique electronic properties that make them excellent candidates for next-generation device technologies. While nanotube growth and processing methods have progressed steadily, significant opportunities remain in advanced methods for their characterization, inspection, and metrology. Microwave near-field imaging offers an extremely versatile "nondestructive" tool for nanomaterials characterization. Herein, we report the application of nanoscale microwave reflectivity to study SWNT electronic properties. Using microwave impedance microscopy (MIM) combined with microwave impedance modulation microscopy (MIM(2)), we imaged horizontal SWNT arrays, showing the microwave reflectivity from individual nanotubes is extremely sensitive to their electronic properties and dependent on the nanotube quantum capacitance under proper experimental conditions. It is shown experimentally that MIM can be a direct probe of the nanotube-free carrier density and the details of their electronic band structure. We demonstrate spatial mapping of local SWNT impedance (MIM), the density of states (MIM(2)), and the nanotube structural morphology (AFM) simultaneously and with lateral resolution down to <50 nm. Nanoscale microwave reflectivity could have tremendous impact, enabling optimization of enriched growth processes and postgrowth purification of SWNT arrays while aiding in the analysis of the quantum physics of these important 1D materials.
Collapse
Affiliation(s)
- Eric Seabron
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Scott MacLaren
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Xu Xie
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Slava V Rotkin
- Department of Physics and Center for Advanced Materials and Nanotechnology, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - John A Rogers
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - William L Wilson
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
- Center for Nanoscale Systems, Harvard University , Cambridge, Massachusetts 02138, United States
| |
Collapse
|
10
|
Biagi MC, Fabregas R, Gramse G, Van Der Hofstadt M, Juárez A, Kienberger F, Fumagalli L, Gomila G. Nanoscale Electric Permittivity of Single Bacterial Cells at Gigahertz Frequencies by Scanning Microwave Microscopy. ACS NANO 2016; 10:280-8. [PMID: 26643251 DOI: 10.1021/acsnano.5b04279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We quantified the electric permittivity of single bacterial cells at microwave frequencies and nanoscale spatial resolution by means of near-field scanning microwave microscopy. To this end, calibrated complex admittance images have been obtained at ∼19 GHz and analyzed with a methodology that removes the nonlocal topographic cross-talk contributions and thus provides quantifiable intrinsic dielectric images of the bacterial cells. Results for single Escherichia coli cells provide a relative electric permittivity of ∼4 in dry conditions and ∼20 in humid conditions, with no significant loss contributions. Present findings, together with the ability of microwaves to penetrate the cell membrane, open an important avenue in the microwave label-free imaging of single cells with nanoscale spatial resolution.
Collapse
Affiliation(s)
- Maria Chiara Biagi
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Rene Fabregas
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Georg Gramse
- Institute for Biophysics, Johannes Kepler University Linz , Gruberst. 40, 4020 Linz, Austria
| | - Marc Van Der Hofstadt
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Antonio Juárez
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
- Departament de Microbiologia, Universitat de Barcelona , Av. Diagonal 643, 08028 Barcelona, Spain
| | - Ferry Kienberger
- Keysight Lab, Keysight Technologies Austria GmbH , Gruberst. 40, 4020 Linz, Austria
| | - Laura Fumagalli
- School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
- Departament d'Electrònica, Universitat de Barcelona , C/Martí i Franqués 1, 08028 Barcelona, Spain
| |
Collapse
|
11
|
Berweger S, Blanchard PT, Brubaker MD, Coakley KJ, Sanford NA, Wallis TM, Bertness KA, Kabos P. Near-Field Control and Imaging of Free Charge Carrier Variations in GaN Nanowires. APPLIED PHYSICS LETTERS 2016; 108:10.1063/1.4942107. [PMID: 38486617 PMCID: PMC10938853 DOI: 10.1063/1.4942107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Despite their uniform crystallinity, the shape and faceting of semiconducting nanowires (NWs) can give rise to variations in structure and associated electronic properties. Here we develop a hybrid scanning probe-based methodology to investigate local variations in electronic structure across individual n-doped GaN NWs integrated into a transistor device. We perform scanning microwave microscopy (SMM), which we combine with scanning gate microscopy (SGM) to determine the free-carrier SMM signal contribution and image local charge carrier density variations. In particular, we find significant variations in free carriers across NWs, with a higher carrier density at the wire facets. By increasing the local carrier density through tip-gating, we find that the tip injects current into the NW with strongly localized current when positioned over the wire vertices. These results suggest that the strong variations in electronic properties observed within NWs have significant implications for device design and may lead to new paths to optimization.
Collapse
Affiliation(s)
- Samuel Berweger
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Paul T Blanchard
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Matt D Brubaker
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Kevin J Coakley
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Norman A Sanford
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Thomas M Wallis
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Kris A Bertness
- National Institute of Standards and Technology, Boulder, CO, 80305
| | - Pavel Kabos
- National Institute of Standards and Technology, Boulder, CO, 80305
| |
Collapse
|
12
|
Charge-order domain walls with enhanced conductivity in a layered manganite. Nat Commun 2015; 6:7595. [PMID: 26139185 PMCID: PMC4506533 DOI: 10.1038/ncomms8595] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/21/2015] [Indexed: 11/08/2022] Open
Abstract
Interfaces and boundaries in condensed-matter systems often have electronic properties distinct from the bulk material and thus have become a topic of both fundamental scientific interest and technological importance. Here we identify, using microwave impedance microscopy, enhanced conductivity of charge-order domain walls in the layered manganite Pr(Sr0.1Ca0.9)2Mn2O7. We obtain a complete mesoscopic map of surface topography, crystalline orientation and electronic phase, and visualize the thermal phase transition between two charge-ordered phases. In both phases, charge-order domains occur with domain walls showing enhanced conductivity likely due to local lifting of the charge order. Finite element analysis shows that the resolved domain walls can be as narrow as few nanometres. The domain walls are stabilized by structural twins and have a strong history dependence, suggesting that they may be manipulated to create novel devices.
Collapse
|
13
|
Pentsak EO, Kashin AS, Polynski MV, Kvashnina KO, Glatzel P, Ananikov VP. Spatial imaging of carbon reactivity centers in Pd/C catalytic systems. Chem Sci 2015; 6:3302-3313. [PMID: 29511504 PMCID: PMC5830937 DOI: 10.1039/c5sc00802f] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 03/31/2015] [Indexed: 12/24/2022] Open
Abstract
Gaining insight into Pd/C catalytic systems aimed at locating reactive centers on carbon surfaces, revealing their properties and estimating the number of reactive centers presents a challenging problem. In the present study state-of-the-art experimental techniques involving ultra high resolution SEM/STEM microscopy (1 Å resolution), high brilliance X-ray absorption spectroscopy and theoretical calculations on truly nanoscale systems were utilized to reveal the role of carbon centers in the formation and nature of Pd/C catalytic materials. Generation of Pd clusters in solution from the easily available Pd2dba3 precursor and the unique reactivity of the Pd clusters opened an excellent opportunity to develop an efficient procedure for the imaging of a carbon surface. Defect sites and reactivity centers of a carbon surface were mapped in three-dimensional space with high resolution and excellent contrast using a user-friendly nanoscale imaging procedure. The proposed imaging approach takes advantage of the specific interactions of reactive carbon centers with Pd clusters, which allows spatial information about chemical reactivity across the Pd/C system to be obtained using a microscopy technique. Mapping the reactivity centers with Pd markers provided unique information about the reactivity of the graphene layers and showed that >2000 reactive centers can be located per 1 μm2 of the surface area of the carbon material. A computational study at a PBE-D3-GPW level differentiated the relative affinity of the Pd2 species to the reactive centers of graphene. These findings emphasized the spatial complexity of the carbon material at the nanoscale and indicated the importance of the surface defect nature, which exhibited substantial gradients and variations across the surface area. The findings show the crucial role of the structure of the carbon support, which governs the formation of Pd/C systems and their catalytic activity.
Collapse
Affiliation(s)
- E O Pentsak
- Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , Moscow , 119991 , Russia .
| | - A S Kashin
- Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , Moscow , 119991 , Russia .
| | - M V Polynski
- Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , Moscow , 119991 , Russia .
- Faculty of Chemistry , Moscow State University , Leninskiye Gory , Moscow , 119991 , Russia
| | - K O Kvashnina
- ESRF - The European Synchrotron , 71 avenue des Martyrs , 38000 Grenoble , France
| | - P Glatzel
- ESRF - The European Synchrotron , 71 avenue des Martyrs , 38000 Grenoble , France
| | - V P Ananikov
- Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , Moscow , 119991 , Russia .
- Department of Chemistry , Saint Petersburg State University , Stary Petergof , 198504 , Russia
| |
Collapse
|
14
|
Berweger S, Weber JC, John J, Velazquez JM, Pieterick A, Sanford NA, Davydov AV, Brunschwig B, Lewis NS, Wallis TM, Kabos P. Microwave near-field imaging of two-dimensional semiconductors. NANO LETTERS 2015; 15:1122-1127. [PMID: 25625509 DOI: 10.1021/nl504960u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Optimizing new generations of two-dimensional devices based on van der Waals materials will require techniques capable of measuring variations in electronic properties in situ and with nanometer spatial resolution. We perform scanning microwave microscopy (SMM) imaging of single layers of MoS2 and n- and p-doped WSe2. By controlling the sample charge carrier concentration through the applied tip bias, we are able to reversibly control and optimize the SMM contrast to image variations in electronic structure and the localized effects of surface contaminants. By further performing tip bias-dependent point spectroscopy together with finite element simulations, we distinguish the effects of the quantum capacitance and determine the local dominant charge carrier species and dopant concentration. These results underscore the capability of SMM for the study of 2D materials to image, identify, and study electronic defects.
Collapse
Affiliation(s)
- Samuel Berweger
- National Institute of Standards and Technology , Boulder, Colorado 80305, United States
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Facile approach to the electrochemical synthesis of palladium-reduced graphene oxide and its application for Suzuki coupling reaction. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2013.12.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
16
|
Tselev A, Lavrik NV, Vlassiouk I, Briggs DP, Rutgers M, Proksch R, Kalinin SV. Near-field microwave scanning probe imaging of conductivity inhomogeneities in CVD graphene. NANOTECHNOLOGY 2012; 23:385706. [PMID: 22948033 DOI: 10.1088/0957-4484/23/38/385706] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have performed near-field scanning microwave microscopy (SMM) of graphene grown by chemical vapor deposition. Due to the use of probe-sample capacitive coupling and a relatively high ac frequency of a few GHz, this scanning probe method allows mapping of local conductivity without a dedicated counter electrode, with a spatial resolution of about 50 nm. Here, the coupling was enabled by atomic layer deposition of alumina on top of graphene, which in turn enabled imaging both large-area films, as well as micron-sized islands, with a dynamic range covering a low sheet resistance of a metal film and a high resistance of highly disordered graphene. The structures of graphene grown on Ni films and Cu foils are explored, and the effects of growth conditions are elucidated. We present a simple general scheme for interpretation of the contrast in the SMM images of our graphene samples and other two-dimensional conductors, which is supported by extensive numerical finite-element modeling. We further demonstrate that combination of the SMM and numerical modeling allows quantitative information about the sheet resistance of graphene to be obtained, paving the pathway for characterization of graphene conductivity with a sub-100 nm special resolution.
Collapse
Affiliation(s)
- Alexander Tselev
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | | | | | | | | | | | | |
Collapse
|
17
|
Affiliation(s)
- George W. Flynn
- Department of Chemistry, Nanoscale Science and Engineering Center, and Energy Frontier Research Center, Columbia University, 3000 Broadway, MC 3109, New York, New York 10027, USA
| |
Collapse
|
18
|
|
19
|
Kundhikanjana W, Lai K, Kelly MA, Shen ZX. Cryogenic microwave imaging of metal-insulator transition in doped silicon. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:033705. [PMID: 21456749 DOI: 10.1063/1.3554438] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the instrumentation and experimental results of a cryogenic scanning microwave impedance microscope. The microwave probe and the scanning stage are located inside the variable temperature insert of a helium cryostat. Microwave signals in the distance modulation mode are used for monitoring the tip-sample distance and adjusting the phase of the two output channels. The ability to spatially resolve the metal-insulator transition in a doped silicon sample is demonstrated. The data agree with a semiquantitative finite element simulation. Effects of the thermal energy and electric fields on local charge carriers can be seen in the images taken at different temperatures and dc biases.
Collapse
Affiliation(s)
- Worasom Kundhikanjana
- Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | | | | | | |
Collapse
|
20
|
Hilder M, Winther-Jensen B, Li D, Forsyth M, MacFarlane DR. Direct electro-deposition of graphene from aqueous suspensions. Phys Chem Chem Phys 2011; 13:9187-93. [DOI: 10.1039/c1cp20173e] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
21
|
Zhang L, Ju Y, Hosoi A, Fujimoto A. Microwave atomic force microscopy imaging for nanometer-scale electrical property characterization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:123708. [PMID: 21198033 DOI: 10.1063/1.3525058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We introduce a new type of microscopy which is capable of investigating surface topography and electrical property of conductive and dielectric materials simultaneously on a nanometer scale. The microwave atomic force microscopy is a combination of the principles of the scanning probe microscope and the microwave-measurement technique. As a result, under the noncontact AFM working conditions, we successfully generated a microwave image of a 200-nm Au film coating on a glass wafer substrate with a spatial resolution of 120 nm and a measured voltage difference of 19.2 mV between the two materials.
Collapse
Affiliation(s)
- Lan Zhang
- Department of Mechanical Science and Engineering, Nagoya University, Furo-Cho, Chikusa-ku, Nagoya 4648603, Japan
| | | | | | | |
Collapse
|
22
|
Talanov VV, Del Barga C, Wickey L, Kalichava I, Gonzales E, Shaner EA, Gin AV, Kalugin NG. Few-layer graphene characterization by near-field scanning microwave microscopy. ACS NANO 2010; 4:3831-3838. [PMID: 20536187 DOI: 10.1021/nn100493f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Near-field scanning microwave microscopy is employed for quantitative imaging at 4 GHz of the local impedance for monolayer and few-layer graphene. The microwave response of graphene is found to be thickness dependent and determined by the local sheet resistance of the graphene flake. Calibration of the measurement system and knowledge of the probe geometry allows evaluation of the AC impedance for monolayer and few-layer graphene, which is found to be predominantly active. The use of localized evanescent electromagnetic field in our experiment provides a promising tool for investigations of plasma waves in graphene with wave numbers determined by the spatial spectrum of the near-field. By using near-field microwave microscopy one can perform simultaneous imaging of location, geometry, thickness, and distribution of electrical properties of graphene without a need for device fabrication.
Collapse
|