1
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Kumar S, Dehm S, Krupke R. On the mechanism of piezoresistance in nanocrystalline graphite. Beilstein J Nanotechnol 2024; 15:376-384. [PMID: 38633765 PMCID: PMC11022366 DOI: 10.3762/bjnano.15.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024]
Abstract
Strain sensors are sensitive to mechanical deformations and enable the detection of strain also within integrated electronics. For flexible displays, the use of a seamlessly integrated strain sensor would be beneficial, and graphene is already in use as a transparent and flexible conductor. However, graphene intrinsically lacks a strong response, and only by engineering defects, such as grain boundaries, one can induce piezoresistivity. Nanocrystalline graphene (NCG), a derivative form of graphene, exhibits a high density of defects in the form of grain boundaries. It holds an advantage over graphene in easily achieving wafer-scale growth with controlled thickness. In this study, we explore the piezoresistivity in thin films of nanocrystalline graphite. Simultaneous measurements of sheet resistance and externally applied strain on NCG placed on polyethylene terephthalate (PET) substrates provide intriguing insights into the underlying mechanism. Raman measurements, in conjunction with strain applied to NCG grown on flexible glass, indicate that the strain is concentrated at the grain boundaries for smaller strain values. For larger strains, mechanisms such as grain rotation and the formation of nanocracks might contribute to the piezoresistive behavior in nanocrystalline graphene.
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Affiliation(s)
- Sandeep Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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2
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Li MK, Dehm S, Kappes MM, Hennrich F, Krupke R. Correlation Measurements for Carbon Nanotubes with Quantum Defects. ACS Nano 2024; 18:9525-9534. [PMID: 38513118 DOI: 10.1021/acsnano.3c12530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Single-photon sources are essential building blocks for the development of photonic quantum technology. Regarding potential practical application, an on-demand electrically driven quantum-light emitter on a chip is notably crucial for photonic integrated circuits. Here, we propose functionalized single-walled carbon nanotube field-effect transistors as a promising solid-state quantum-light source by demonstrating photon antibunching behavior via electrical excitation. The sp3 quantum defects were formed on the surface of (7, 5) carbon nanotubes by 3,5-dichlorophenyl functionalization, and individual carbon nanotubes were wired to graphene electrode pairs. Filtered electroluminescent defect-state emission at 77 K was coupled into a Hanbury Brown and Twiss experiment setup, and single-photon emission was observed by performing second-order correlation function measurements. We discuss the dependence of the intensity correlation measurement on electrical power and emission wavelength, highlighting the challenges of performing such measurements while simultaneously analyzing acquired data. Our results indicate a route toward room-temperature electrically triggered single-photon emission.
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Affiliation(s)
- Min-Ken Li
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Manfred M Kappes
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Frank Hennrich
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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3
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Ovvyan AP, Li MK, Gehring H, Beutel F, Kumar S, Hennrich F, Wei L, Chen Y, Pyatkov F, Krupke R, Pernice WHP. An electroluminescent and tunable cavity-enhanced carbon-nanotube-emitter in the telecom band. Nat Commun 2023; 14:3933. [PMID: 37402723 DOI: 10.1038/s41467-023-39622-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 06/20/2023] [Indexed: 07/06/2023] Open
Abstract
Emerging photonic information processing systems require chip-level integration of controllable nanoscale light sources at telecommunication wavelengths. Currently, substantial challenges remain in the dynamic control of the sources, the low-loss integration into a photonic environment, and in the site-selective placement at desired positions on a chip. Here, we overcome these challenges using heterogeneous integration of electroluminescent (EL), semiconducting carbon nanotubes (sCNTs) into hybrid two dimensional - three dimensional (2D-3D) photonic circuits. We demonstrate enhanced spectral line shaping of the EL sCNT emission. By back-gating the sCNT-nanoemitter we achieve full electrical dynamic control of the EL sCNT emission with high on-off ratio and strong enhancement in the telecommunication band. Using nanographene as a low-loss material to electrically contact sCNT emitters directly within a photonic crystal cavity enables highly efficient EL coupling without compromising the optical quality of the cavity. Our versatile approach paves the way for controllable integrated photonic circuits.
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Affiliation(s)
- Anna P Ovvyan
- University of Münster, Physikalisches Institut, Center for Nanotechnology, Heisenbergstr. 11, 48149, Münster, Germany
| | - Min-Ken Li
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Helge Gehring
- University of Münster, Physikalisches Institut, Center for Nanotechnology, Heisenbergstr. 11, 48149, Münster, Germany
| | - Fabian Beutel
- University of Münster, Physikalisches Institut, Center for Nanotechnology, Heisenbergstr. 11, 48149, Münster, Germany
| | - Sandeep Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Frank Hennrich
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Li Wei
- The University of Sydney, School of Chemical and Biomolecular Engineering, Darlington, NSW, 2006, Australia
| | - Yuan Chen
- The University of Sydney, School of Chemical and Biomolecular Engineering, Darlington, NSW, 2006, Australia
| | - Felix Pyatkov
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Wolfram H P Pernice
- University of Münster, Physikalisches Institut, Center for Nanotechnology, Heisenbergstr. 11, 48149, Münster, Germany.
- Center for Soft Nanoscience, Busso-Peuss-Str. 11, 48149, Münster, Germany.
- Kirchhoff-Institut for Physics, Im Neuenheimer Feld 227, 69120, Heidelberg, Germany.
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4
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Li MK, Riaz A, Wederhake M, Fink K, Saha A, Dehm S, He X, Schöppler F, Kappes MM, Htoon H, Popov VN, Doorn SK, Hertel T, Hennrich F, Krupke R. Electroluminescence from Single-Walled Carbon Nanotubes with Quantum Defects. ACS Nano 2022; 16:11742-11754. [PMID: 35732039 DOI: 10.1021/acsnano.2c03083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Individual single-walled carbon nanotubes with covalent sidewall defects have emerged as a class of photon sources whose photoluminescence spectra can be tailored by the carbon nanotube chirality and the attached functional group/molecule. Here we present electroluminescence spectroscopy data from single-tube devices based on (7, 5) carbon nanotubes, functionalized with dichlorobenzene molecules, and wired to graphene electrodes. We observe electrically generated, defect-induced emissions that are controllable by electrostatic gating and strongly red-shifted compared to emissions from pristine nanotubes. The defect-induced emissions are assigned to excitonic and trionic recombination processes by correlating electroluminescence excitation maps with electrical transport and photoluminescence data. At cryogenic conditions, additional gate-dependent emission lines appear, which are assigned to phonon-assisted hot-exciton electroluminescence from quasi-levels. Similar results were obtained with functionalized (6, 5) nanotubes. We also compare functionalized (7, 5) electroluminescence data with photoluminescence of pristine and functionalized (7, 5) nanotubes redox-doped using gold(III) chloride solution. This work shows that electroluminescence excitation is selective toward neutral defect-state configurations with the lowest transition energy, which in combination with gate-control over neutral versus charged defect-state emission leads to high spectral purity.
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Affiliation(s)
- Min-Ken Li
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Adnan Riaz
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Martina Wederhake
- Institute of Physical and Theoretical Chemistry, Julius Maximilian University Würzburg, Würzburg 97074, Germany
| | - Karin Fink
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Avishek Saha
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Xiaowei He
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Friedrich Schöppler
- Institute of Physical and Theoretical Chemistry, Julius Maximilian University Würzburg, Würzburg 97074, Germany
| | - Manfred M Kappes
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany
| | - Han Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | | | - Stephen K Doorn
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Tobias Hertel
- Institute of Physical and Theoretical Chemistry, Julius Maximilian University Würzburg, Würzburg 97074, Germany
| | - Frank Hennrich
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
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5
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Peyyety NA, Kumar S, Li MK, Dehm S, Krupke R. Tailoring Spectrally Flat Infrared Photodetection with Thickness-Controlled Nanocrystalline Graphite. ACS Appl Mater Interfaces 2022; 14:9525-9534. [PMID: 35138788 DOI: 10.1021/acsami.1c24306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Graphene, a zero-gap semiconductor, absorbs 2.3% of incident photons in a wide wavelength range as a free-standing monolayer, whereas 50% is expected for ∼90 layers. Adjusting the layer number allows the tailoring of the photoresponse; however, controlling the thickness of multilayer graphene remains challenging on the wafer scale. Nanocrystalline graphene or graphite (NCG) can instead be grown with controlled thickness. We have fabricated photodetectors from NCG that are spectrally flat in the near-infrared to short-wavelength infrared region by tailoring the layer thicknesses. Transfer matrix simulations were used to determine the NCG thickness for maximum light absorption in the NCG layer on a silicon substrate. The extrinsic and intrinsic photoresponse was determined from 1100 to 2100 nm using chromatic aberration-corrected photocurrent spectroscopy. Diffraction-limited hyperspectral photocurrent imaging shows that the biased photoresponse is unipolar and homogeneous across the device area, whereas the short-circuit photoresponse gives rise to positive and negative photocurrents at the electrodes. The intrinsic photoresponses are wavelength-independent, indicative of bolometric and electrothermal photodetection.
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Affiliation(s)
- Naga Anirudh Peyyety
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Sandeep Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Min-Ken Li
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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6
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Kumar S, Pramudya Y, Müller K, Chandresh A, Dehm S, Heidrich S, Fediai A, Parmar D, Perera D, Rommel M, Heinke L, Wenzel W, Wöll C, Krupke R. Sensing Molecules with Metal-Organic Framework Functionalized Graphene Transistors. Adv Mater 2021; 33:e2103316. [PMID: 34496451 DOI: 10.1002/adma.202103316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Graphene is inherently sensitive to vicinal dielectrics and local charge distributions, a property that can be probed by the position of the Dirac point in graphene field-effect transistors. Exploiting this as a useful sensing principle requires selectivity; however, graphene itself exhibits no molecule-specific interaction. Complementarily, metal-organic frameworks can be tailored to selective adsorption of specific molecular species. Here, a selective ethanol sensor is demonstrated by growing a surface-mounted metal-organic framework (SURMOF) directly onto graphene field-effect transistors (GFETs). Unprecedented shifts of the Dirac point, as large as 15 V, are observed when the SURMOF/GFET is exposed to ethanol, while a vanishingly small response is observed for isopropanol, methanol, and other constituents of the air, including water. The synthesis and conditioning of the hybrid materials sensor with its functional characteristics are described and a model is proposed to explain the origin, magnitude, and direction of the Dirac point voltage shift. Tailoring multiple SURMOFs to adsorb specific gases on an array of such devices thus generates a versatile, selective, and highly sensitive platform for sensing applications.
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Affiliation(s)
- Sandeep Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Yohanes Pramudya
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Kai Müller
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Abhinav Chandresh
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Shahriar Heidrich
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Artem Fediai
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Devang Parmar
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Delwin Perera
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Manuel Rommel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Lars Heinke
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Christof Wöll
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287, Darmstadt, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
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7
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Kraft R, Liu MH, Selvasundaram PB, Chen SC, Krupke R, Richter K, Danneau R. Anomalous Cyclotron Motion in Graphene Superlattice Cavities. Phys Rev Lett 2020; 125:217701. [PMID: 33275010 DOI: 10.1103/physrevlett.125.217701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
We consider graphene superlattice miniband fermions probed by electronic interferometry in magnetotransport experiments. By decoding the observed Fabry-Pérot interference patterns together with our corresponding quantum transport simulations, we find that the Dirac quasiparticles originating from the superlattice minibands do not undergo conventional cyclotron motion but follow more subtle trajectories. In particular, dynamics at low magnetic fields is characterized by peculiar, straight trajectory segments. Our results provide new insights into superlattice miniband fermions and open up novel possibilities to use periodic potentials in electron optics experiments.
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Affiliation(s)
- Rainer Kraft
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
- Institute of Physics, Karlsruhe Institute of Technology, Karlsruhe D-76049, Germany
| | - Ming-Hao Liu
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Pranauv Balaji Selvasundaram
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt, Darmstadt D-64287, Germany
| | - Szu-Chao Chen
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt, Darmstadt D-64287, Germany
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
| | - Klaus Richter
- Institut für Theoretische Physik, Universität Regensburg, Regensburg D-93040, Germany
| | - Romain Danneau
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany
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8
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Nagyte V, Kelly DJ, Felten A, Picardi G, Shin Y, Alieva A, Worsley RE, Parvez K, Dehm S, Krupke R, Haigh SJ, Oikonomou A, Pollard AJ, Casiraghi C. Raman Fingerprints of Graphene Produced by Anodic Electrochemical Exfoliation. Nano Lett 2020; 20:3411-3419. [PMID: 32233490 DOI: 10.1021/acs.nanolett.0c00332] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Electrochemical exfoliation is one of the most promising methods for scalable production of graphene. However, limited understanding of its Raman spectrum as well as lack of measurement standards for graphene strongly limit its industrial applications. In this work, we show a systematic study of the Raman spectrum of electrochemically exfoliated graphene, produced using different electrolytes and types of solvents in varying amounts. We demonstrate that no information on the thickness can be extracted from the shape of the 2D peak as this type of graphene is defective. Furthermore, the number of defects and the uniformity of the samples strongly depend on the experimental conditions, including postprocessing. Under specific conditions, the formation of short conductive trans-polyacetylene chains has been observed. Our Raman analysis provides guidance for the community on how to get information on defects coming from electrolyte, temperature, and other experimental conditions, by making Raman spectroscopy a powerful metrology tool.
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Affiliation(s)
- Vaiva Nagyte
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Daniel J Kelly
- Department of Materials, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Alexandre Felten
- Synthesis, Irradiation and Analysis of Materials (SIAM), University of Namur, Namur 5000, Belgium
| | - Gennaro Picardi
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - YuYoung Shin
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Adriana Alieva
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Robyn E Worsley
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Khaled Parvez
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt, Darmstadt 64287, Germany
| | - Sarah J Haigh
- Department of Materials, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Antonios Oikonomou
- National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
- The Institute of Photonic Sciences, Castelldefels 08860, Spain
| | - Andrew J Pollard
- National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - Cinzia Casiraghi
- Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
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9
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Gaulke M, Janissek A, Peyyety NA, Alamgir I, Riaz A, Dehm S, Li H, Lemmer U, Flavel BS, Kappes MM, Hennrich F, Wei L, Chen Y, Pyatkov F, Krupke R. Low-Temperature Electroluminescence Excitation Mapping of Excitons and Trions in Short-Channel Monochiral Carbon Nanotube Devices. ACS Nano 2020; 14:2709-2717. [PMID: 31920075 DOI: 10.1021/acsnano.9b07207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Single-walled carbon nanotubes as emerging quantum-light sources may fill a technological gap in silicon photonics due to their potential use as near-infrared, electrically driven, classical or nonclassical emitters. Unlike in photoluminescence, where nanotubes are excited with light, electrical excitation of single tubes is challenging and heavily influenced by device fabrication, architecture, and biasing conditions. Here we present electroluminescence spectroscopy data of ultra-short-channel devices made from (9,8) carbon nanotubes emitting in the telecom band. Emissions are stable under current biasing, and no enhanced suppression is observed down to 10 nm gap size. Low-temperature electroluminescence spectroscopy data also reported exhibit cold emission and line widths down to 2 meV at 4 K. Electroluminescence excitation maps give evidence that carrier recombination is the mechanism for light generation in short channels. Excitonic and trionic emissions can be switched on and off by gate voltage, and corresponding emission efficiency maps were compiled. Insights are gained into the influence of acoustic phonons on the line width, absence of intensity saturation and exciton-exciton annihilation, environmental effects such as dielectric screening and strain on the emission wavelength, and conditions to suppress hysteresis and establish optimum operation conditions.
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Affiliation(s)
- Marco Gaulke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Alexander Janissek
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Naga Anirudh Peyyety
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Imtiaz Alamgir
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Adnan Riaz
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Han Li
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Uli Lemmer
- Light Technology Institute, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Benjamin S Flavel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Manfred M Kappes
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany
| | - Frank Hennrich
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Li Wei
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Yuan Chen
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Felix Pyatkov
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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10
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Li H, Gordeev G, Garrity O, Peyyety NA, Selvasundaram PB, Dehm S, Krupke R, Cambré S, Wenseleers W, Reich S, Zheng M, Fagan JA, Flavel BS. Separation of Specific Single-Enantiomer Single-Wall Carbon Nanotubes in the Large-Diameter Regime. ACS Nano 2020; 14:948-963. [PMID: 31742998 PMCID: PMC6994058 DOI: 10.1021/acsnano.9b08244] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 11/19/2019] [Indexed: 05/06/2023]
Abstract
The enantiomer-level isolation of single-walled carbon nanotubes (SWCNTs) in high concentration and with high purity for nanotubes greater than 1.1 nm in diameter is demonstrated using a two-stage aqueous two-phase extraction (ATPE) technique. In total, five different nanotube species of ∼1.41 nm diameter are isolated, including both metallics and semiconductors. We characterize these populations by absorbance spectroscopy, circular dichroism spectroscopy, resonance Raman spectroscopy, and photoluminescence mapping, revealing and substantiating mod-dependent optical dependencies. Using knowledge of the competitive adsorption of surfactants to the SWCNTs that controls partitioning within the ATPE separation, we describe an advanced acid addition methodology that enables the fine control of the separation of these select nanotubes. Furthermore, we show that endohedral filling is a previously unrecognized but important factor to ensure a homogeneous starting material and further enhance the separation yield, with the best results for alkane-filled SWCNTs, followed by empty SWCNTs, with the intrinsic inhomogeneity of water-filled SWCNTs causing them to be worse for separations. Lastly, we demonstrate the potential use of these nanotubes in field-effect transistors.
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Affiliation(s)
- Han Li
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
| | - Georgy Gordeev
- Department
of Physics, Freie Universität Berlin, Berlin 14195, Germany
| | - Oisin Garrity
- Department
of Physics, Freie Universität Berlin, Berlin 14195, Germany
| | - Naga Anirudh Peyyety
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
- Institute
of Materials Science, Technische Universität
Darmstadt, Darmstadt 64287, Germany
| | - Pranauv Balaji Selvasundaram
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
- Institute
of Materials Science, Technische Universität
Darmstadt, Darmstadt 64287, Germany
| | - Simone Dehm
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
| | - Ralph Krupke
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
- Institute
of Materials Science, Technische Universität
Darmstadt, Darmstadt 64287, Germany
| | - Sofie Cambré
- Physics
Department, University of Antwerp, Antwerp 2020, Belgium
| | - Wim Wenseleers
- Physics
Department, University of Antwerp, Antwerp 2020, Belgium
| | - Stephanie Reich
- Department
of Physics, Freie Universität Berlin, Berlin 14195, Germany
| | - Ming Zheng
- Materials
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jeffrey A. Fagan
- Materials
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Benjamin S. Flavel
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Karlsruhe 76021, Germany
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11
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Kumar CNS, Konrad M, Chakravadhanula VSK, Dehm S, Wang D, Wenzel W, Krupke R, Kübel C. Nanocrystalline graphene at high temperatures: insight into nanoscale processes. Nanoscale Adv 2019; 1:2485-2494. [PMID: 36132723 PMCID: PMC9419052 DOI: 10.1039/c9na00055k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/23/2019] [Indexed: 06/13/2023]
Abstract
During high temperature pyrolysis of polymer thin films, nanocrystalline graphene with a high defect density, active edges and various nanostructures is formed. The catalyst-free synthesis is based on the temperature assisted transformation of a polymer precursor. The processing conditions have a strong influence on the final thin film properties. However, the precise elemental processes that govern the polymer pyrolysis at high temperatures are unknown. By means of time resolved in situ transmission electron microscopy investigations we reveal that the reactivity of defects and unsaturated edges plays an integral role in the structural dynamics. Both mobile and stationary structures with varying size, shape and dynamics have been observed. During high temperature experiments, small graphene fragments (nanoflakes) are highly unstable and tend to lose atoms or small groups of atoms, while adjacent larger domains grow by addition of atoms, indicating an Ostwald-like ripening in these 2D materials, besides the mechanism of lateral merging of nanoflakes with edges. These processes are also observed in low-dose experiments with negligible electron beam influence. Based on energy barrier calculations, we propose several inherent temperature-driven mechanisms of atom rearrangement, partially involving catalyzing unsaturated sites. Our results show that the fundamentally different high temperature behavior and stability of nanocrystalline graphene in contrast to pristine graphene is caused by its reactive nature. The detailed analysis of the observed dynamics provides a pioneering overview of the relevant processes during ncg heating.
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Affiliation(s)
- C N Shyam Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt 64287 Darmstadt Germany
| | - Manuel Konrad
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
| | | | - Simone Dehm
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
| | - Di Wang
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
- Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt 64287 Darmstadt Germany
| | - Christian Kübel
- Institute of Nanotechnology, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt 64287 Darmstadt Germany
- Helmholtz Institute Ulm, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
- Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology 76021 Karlsruhe Germany
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12
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He X, Htoon H, Doorn SK, Pernice WHP, Pyatkov F, Krupke R, Jeantet A, Chassagneux Y, Voisin C. Author Correction: Carbon nanotubes as emerging quantum-light sources. Nat Mater 2019; 18:770. [PMID: 31118489 DOI: 10.1038/s41563-019-0406-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- X He
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - H Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - S K Doorn
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - W H P Pernice
- Institute of Physics, University of Münster, Münster, Germany
| | - F Pyatkov
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - R Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - A Jeantet
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - Y Chassagneux
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - C Voisin
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France.
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13
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Selvasundaram PB, Kraft R, Li W, Fischer R, Kappes MM, Hennrich F, Krupke R. Measuring in Situ Length Distributions of Polymer-Wrapped Monochiral Single-Walled Carbon Nanotubes Dispersed in Toluene with Analytical Ultracentrifugation. Langmuir 2019; 35:3790-3796. [PMID: 30758209 DOI: 10.1021/acs.langmuir.9b00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The length of a carbon nanotube is an important dimension that has to be adjusted to the requirements of an experiment or application, e.g., through sorting methods. So far, atomic force microscopy (AFM) has been the method of choice for measuring length distributions, despite being an ex situ method with apparent shortcomings. In this work, we explore analytical ultracentrifugation (AUC) as an in situ method for measuring the length distribution of polymer-wrapped (7, 5) single-walled carbon nanotubes dispersed in toluene. This is an AUC study of nanotubes in nonaqueous media, the preferred media for nanotubes used in device fabrication. In AUC, the temporally and spatially dependent change in optical absorption of a sample is measured under centrifugation. The resulting sedimentation curves can be deconvoluted with a standard data processing procedure (SEDFIT), to yield the sedimentation coefficient distribution. However, the conversion of the sedimentation coefficient distribution into a length distribution is nontrivial and requires finding a suitable model for the nanotube friction coefficient. Also, since AUC is based on optical absorption, it yields a volume distribution and not a number distribution as obtained from AFM reference data. By meeting these challenges and finding a surprisingly simple empirical flexible-chain-like model to describe the sedimentation behavior of one specific chiral structure, we suggest AUC as a viable method for measuring in situ nanotube length distributions of nonaqueous dispersions.
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Affiliation(s)
- Pranauv Balaji Selvasundaram
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
- Institute of Materials Science , Technical University Darmstadt , Darmstadt D-64287 , Germany
| | - Rainer Kraft
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
| | - Wenshan Li
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
- Institute of Materials Science , Technical University Darmstadt , Darmstadt D-64287 , Germany
| | - Regina Fischer
- Institute of Physical Chemistry , Karlsruhe Institute of Technology , Karlsruhe D-76131 , Germany
| | - Manfred M Kappes
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
- Institute of Physical Chemistry , Karlsruhe Institute of Technology , Karlsruhe D-76131 , Germany
| | - Frank Hennrich
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
| | - Ralph Krupke
- Institute of Nanotechnology , Karlsruhe Institute of Technology , Karlsruhe D-76021 , Germany
- Institute of Materials Science , Technical University Darmstadt , Darmstadt D-64287 , Germany
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14
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Giambra MA, Benfante A, Pernice R, Miseikis V, Fabbri F, Reitz C, Pernice WHP, Krupke R, Calandra E, Stivala S, Busacca AC, Danneau R. Graphene Field-Effect Transistors Employing Different Thin Oxide Films: A Comparative Study. ACS Omega 2019; 4:2256-2260. [PMID: 31459467 PMCID: PMC6649291 DOI: 10.1021/acsomega.8b02836] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/09/2019] [Indexed: 05/05/2023]
Abstract
In this work, we report on a comparison among graphene field-effect transistors (GFETs) employing different dielectrics as gate layers to evaluate their microwave response. In particular, aluminum oxide (Al2O3), titanium oxide (TiO2), and hafnium oxide (HfO2) have been tested. GFETs have been fabricated on a single chip and a statistical analysis has been performed on a set of 24 devices for each type of oxide. Direct current and microwave measurements have been carried out on such GFETs and short circuit current gain and maximum available gain have been chosen as quality factors to evaluate their microwave performance. Our results show that all of the devices belonging to a specific group (i.e., with the same oxide) have a well-defined performance curve and that the choice of hafnium oxide represents the best trade-off in terms of dielectric properties. Graphene transistors employing HfO2 as the dielectric layer, in fact, exhibit the best performance in terms of both the cutoff frequency and the maximum frequency of oscillation.
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Affiliation(s)
- Marco A. Giambra
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
- E-mail:
| | - Antonio Benfante
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
| | - Riccardo Pernice
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
| | - Vaidotas Miseikis
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
- Graphene Labs, Istituto Italiano
di Tecnologia, Via Morego
30, 16163 Genova, Italy
- CNI@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Filippo Fabbri
- Graphene Labs, Istituto Italiano
di Tecnologia, Via Morego
30, 16163 Genova, Italy
- CNI@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Christian Reitz
- Institute of Nanotechnology, Karlsruhe
Institute of Technology, 76021 Karlsruhe, Germany
| | - Wolfram H. P. Pernice
- Institute of Nanotechnology, Karlsruhe
Institute of Technology, 76021 Karlsruhe, Germany
- Institute
of Physics, University of Münster, Münster 48149, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe
Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Enrico Calandra
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
| | - Salvatore Stivala
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
| | - Alessandro C. Busacca
- Consorzio Nazionale Interuniversitario per le Telecomunicazioni
− CNIT and Department of Engineering, University of Palermo, Viale delle Scienze, Building 9, 90128 Palermo, Italy
| | - Romain Danneau
- Institute of Nanotechnology, Karlsruhe
Institute of Technology, 76021 Karlsruhe, Germany
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15
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Kraft R, Krainov IV, Gall V, Dmitriev AP, Krupke R, Gornyi IV, Danneau R. Valley Subband Splitting in Bilayer Graphene Quantum Point Contacts. Phys Rev Lett 2018; 121:257703. [PMID: 30608811 DOI: 10.1103/physrevlett.121.257703] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Indexed: 06/09/2023]
Abstract
We report a study of one-dimensional subband splitting in a bilayer graphene quantum point contact in which quantized conductance in steps of 4e^{2}/h is clearly defined down to the lowest subband. While our source-drain bias spectroscopy measurements reveal an unconventional confinement, we observe a full lifting of the valley degeneracy at high magnetic fields perpendicular to the bilayer graphene plane for the first two lowest subbands where confinement and Coulomb interactions are the strongest and a peculiar merging or mixing of K and K^{'} valleys from two nonadjacent subbands with indices (N,N+2), which are well described by our semiphenomenological model.
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Affiliation(s)
- R Kraft
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
| | - I V Krainov
- A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
- Lappeenranta University of Technology, P.O. Box 20, 53851 Lappeenranta, Finland
| | - V Gall
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
- Institute for Condensed Matter Theory, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany
| | - A P Dmitriev
- A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
| | - R Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
- Department of Materials and Earth Sciences, Technical University Darmstadt, 64287 Darmstadt, Germany
| | - I V Gornyi
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
- A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
- Institute for Condensed Matter Theory, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany
| | - R Danneau
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
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16
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Du R, Liu MH, Mohrmann J, Wu F, Krupke R, von Löhneysen H, Richter K, Danneau R. Tuning Anti-Klein to Klein Tunneling in Bilayer Graphene. Phys Rev Lett 2018; 121:127706. [PMID: 30296148 DOI: 10.1103/physrevlett.121.127706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/15/2018] [Indexed: 06/08/2023]
Abstract
We show that in gapped bilayer graphene, quasiparticle tunneling and the corresponding Berry phase can be controlled such that they exhibit features of single-layer graphene such as Klein tunneling. The Berry phase is detected by a high-quality Fabry-Pérot interferometer based on bilayer graphene. By raising the Fermi energy of the charge carriers, we find that the Berry phase can be continuously tuned from 2π down to 0.68π in gapped bilayer graphene, in contrast to the constant Berry phase of 2π in pristine bilayer graphene. Particularly, we observe a Berry phase of π, the standard value for single-layer graphene. As the Berry phase decreases, the corresponding transmission probability of charge carriers at normal incidence clearly demonstrates a transition from anti-Klein tunneling to nearly perfect Klein tunneling.
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Affiliation(s)
- Renjun Du
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
| | - Ming-Hao Liu
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Jens Mohrmann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
| | - Fan Wu
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
- College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, China
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
- Institute of Material Science, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Hilbert von Löhneysen
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
- Institute for Solid State Physics and Physics Institute, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
| | - Klaus Richter
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Romain Danneau
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany
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17
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He X, Htoon H, Doorn SK, Pernice WHP, Pyatkov F, Krupke R, Jeantet A, Chassagneux Y, Voisin C. Publisher Correction: Carbon nanotubes as emerging quantum-light sources. Nat Mater 2018; 17:843. [PMID: 29995875 DOI: 10.1038/s41563-018-0141-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the version of this Perspective originally published, the x-axis label of Fig. 1d was missing; it should have read 'Wavelength (nm)'. The units of the y axis of Fig. 3b were incorrect; they should have been meV. And the citation of Fig. 3c in the main text was incorrect; it should have been to Fig. 3b. These issues have now been corrected.
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Affiliation(s)
- X He
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - H Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - S K Doorn
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - W H P Pernice
- Institute of Physics, University of Münster, Münster, Germany
| | - F Pyatkov
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - R Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - A Jeantet
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - Y Chassagneux
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - C Voisin
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France.
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18
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He X, Htoon H, Doorn SK, Pernice WHP, Pyatkov F, Krupke R, Jeantet A, Chassagneux Y, Voisin C. Carbon nanotubes as emerging quantum-light sources. Nat Mater 2018; 17:663-670. [PMID: 29915427 DOI: 10.1038/s41563-018-0109-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/14/2018] [Indexed: 05/18/2023]
Abstract
Progress in quantum computing and quantum cryptography requires efficient, electrically triggered, single-photon sources at room temperature in the telecom wavelengths. It has been long known that semiconducting single-wall carbon nanotubes (SWCNTs) display strong excitonic binding and emit light over a broad range of wavelengths, but their use has been hampered by a low quantum yield and a high sensitivity to spectral diffusion and blinking. In this Perspective, we discuss recent advances in the mastering of SWCNT optical properties by chemistry, electrical contacting and resonator coupling towards advancing their use as quantum light sources. We describe the latest results in terms of single-photon purity, generation efficiency and indistinguishability. Finally, we consider the main fundamental challenges stemming from the unique properties of SWCNTs and the most promising roads for SWCNT-based chip integrated quantum photonic sources.
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Affiliation(s)
- X He
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - H Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - S K Doorn
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - W H P Pernice
- Institute of Physics, University of Münster, Münster, Germany
| | - F Pyatkov
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - R Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - A Jeantet
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - Y Chassagneux
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France
| | - C Voisin
- Laboratoire Pierre Aigrain, École Normale Supérieure, PSL University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Université, CNRS, Paris, France.
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19
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Yekani R, Rusak E, Riaz A, Felten A, Breitung B, Dehm S, Perera D, Rohrer J, Rockstuhl C, Krupke R. Formation of nanocrystalline graphene on germanium. Nanoscale 2018; 10:12156-12162. [PMID: 29916516 DOI: 10.1039/c8nr01261j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Graphitization of a polymer layer provides a convenient route to synthesize nanocrystalline graphene on dielectric surfaces. The transparent and conducting wafer scale material is of interest as a membrane and a coating, and for the generation and detection of light, or strain sensing. In this work, we study the formation of nanocrystalline graphene on germanium, a surface which promotes the CVD synthesis of monocrystalline graphene. The surprising result that we obtained through graphitization is the formation of cavities in germanium, over which nanocrystalline graphene is suspended. Depending on the crystallographic orientation of the germanium surface, either trenches in (110)-Ge or pits in (111)-Ge are formed, and their dimensions depend on the graphitization temperature. Using Raman spatial imaging, we can show that nanocrystalline graphene is formed across the entire wafer in spite of the cavity formation. Interestingly, the Raman intensity is suppressed when the material is supported by germanium and is enhanced when the material is suspended. Through simulations, we can show that these effects are induced by the high refractive index of germanium and by interferences of the light field depending on the spacing between graphene and germanium. Using atomic force and scanning electron microscopy, we determined that ripples in the suspended material are induced by the mismatch of thermal expansion coefficients. Our results provide a new route to lithography-free fabrication of suspended membranes.
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Affiliation(s)
- Rana Yekani
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
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20
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Li H, Gordeev G, Wasserroth S, Chakravadhanula VSK, Neelakandhan SKC, Hennrich F, Jorio A, Reich S, Krupke R, Flavel BS. Inner- and outer-wall sorting of double-walled carbon nanotubes. Nat Nanotechnol 2017; 12:1176-1182. [PMID: 28967894 DOI: 10.1038/nnano.2017.207] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Double-walled carbon nanotubes (DWCNTs) consist of two coaxially aligned single-walled carbon nanotubes (SWCNTs), and previous sorting methods only achieved outer-wall electronic-type selectivity. Here, a separation technique capable of sorting DWCNTs by semiconducting (S) or metallic (M) inner- and outer-wall electronic type is presented. Electronic coupling between the inner and outer wall is used to alter the surfactant coating around each of the DWCNT types, and aqueous gel permeation is used to separate them. Aqueous methods are used to remove SWCNT species from the raw material and prepare enriched DWCNT fractions. The enriched DWCNT fractions are then transferred into either chlorobenzene or toluene using the copolymer PFO-BPy to yield the four inner@outer combinations of M@M, M@S, S@M and S@S. The high purity of the resulting fractions is verified by absorption measurements, transmission electron microscopy, atomic force microscopy, resonance Raman mapping and high-density field-effect transistor devices.
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Affiliation(s)
- Han Li
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Georgy Gordeev
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sören Wasserroth
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Venkata Sai Kiran Chakravadhanula
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Helmholtz Institute Ulm Electrochemical Energy Storage, 89081 Ulm, Germany
| | - Shyam Kumar Chethala Neelakandhan
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Frank Hennrich
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Ado Jorio
- Department of Physics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Stephanie Reich
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Benjamin Scott Flavel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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21
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Shyam Kumar CN, Chakravadhanula VSK, Riaz A, Dehm S, Wang D, Mu X, Flavel B, Krupke R, Kübel C. Understanding the graphitization and growth of free-standing nanocrystalline graphene using in situ transmission electron microscopy. Nanoscale 2017; 9:12835-12842. [PMID: 28799608 DOI: 10.1039/c7nr03276e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Graphitization of polymers is an effective way to synthesize nanocrystalline graphene on different substrates with tunable shape, thickness and properties. The catalyst free synthesis results in crystallite sizes on the order of a few nanometers, significantly smaller than commonly prepared polycrystalline graphene. Even though this method provides the flexibility of graphitizing polymer films on different substrates, substrate free graphitization of freestanding polymer layers has not been studied yet. We report for the first time the thermally induced graphitization and domain growth of free-standing nanocrystalline graphene thin films using in situ TEM techniques. High resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and electron energy loss spectroscopy (EELS) techniques were used to analyze the graphitization and the evolution of nanocrystalline domains at different temperatures by characterizing the crystallinity and domain size, further supported by ex situ Raman spectroscopy. The graphitization was comparable to the substrate supported heating and the temperature dependence of graphitization was analyzed. In addition, the in situ analysis of the graphitization enabled direct imaging of some of the growth processes taking place at different temperatures.
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Affiliation(s)
- C N Shyam Kumar
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.
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22
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Wei L, Flavel BS, Li W, Krupke R, Chen Y. Exploring the upper limit of single-walled carbon nanotube purity by multiple-cycle aqueous two-phase separation. Nanoscale 2017; 9:11640-11646. [PMID: 28770923 DOI: 10.1039/c7nr03302h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ultrahigh purity semiconducting single-walled carbon nanotubes (S-SWCNTs) are required for high-performance transistors. Aqueous two-phase (ATP) separation is an attractive method to obtain such SWCNTs due to its simplicity and scalability. This work targeted two questions; namely what is the upper limit of S-SWCNT purity that can be achieved by multiple cycles of ATP separation from the most commonly used polyethylene glycol and dextran system and how accurately can commonly used methods characterize the improvement in purity? SWCNT purity in nanotube dispersions obtained by multi-cycle ATP separation (2, 4, 6 and 8 cycles) was evaluated by three methods, including UV-vis-NIR absorption spectroscopy analysis, performance of thin-film field effect transistors (FETs) prepared by drop casting and short-channel FET devices prepared by dielectrophoresis deposition. Absorption spectroscopic analysis and the performance of the thin-film FET devices can hardly differentiate metallic SWCNT residues in the dispersions obtained after 4 cycles with the purity above 99.5%, and the short channel FET devices prepared by dielectrophoresis deposition are more sensitive towards tiny metallic SWCNT residues. A new method was also demonstrated to visualize the minor metallic content in the nanotube suspension using voltage contrast imaging in a scanning electron microscope, which enables rapid screening of many devices and the accurate obtainment of metallic content without performing a large number of individual transconductance measurements.
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Affiliation(s)
- Li Wei
- The University of Sydney, School of Chemical and Biomolecular Engineering, NSW 2006, Australia.
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23
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Alam A, Dehm S, Hennrich F, Zakharko Y, Graf A, Pfohl M, Hossain IM, Kappes MM, Zaumseil J, Krupke R, Flavel BS. Photocurrent spectroscopy of dye-sensitized carbon nanotubes. Nanoscale 2017; 9:11205-11213. [PMID: 28749520 DOI: 10.1039/c7nr04022a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Monochiral (7,5) single walled carbon nanotubes (SWCNTs) are integrated into a field effect transistor device in which the built-in electric field at the nanotube/metal contact allows for exciton separation under illumination. Variable wavelength spectroscopy and 2D surface mapping of devices consisting of 10-20 nanotubes are performed in the visible region and a strong correlation between the nanotube's second optical transition (S22) and the photocurrent is found. After integration, the SWCNTs are non-covalently modified with three different fluorescent dye molecules with off-resonant absorption maxima at 532 nm, 565 nm, and 610 nm. The dyes extend the absorption properties of the nanotube and contribute to the photocurrent. This approach holds promise for the development of photo-detectors and for applications in photovoltaics and biosensing.
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Affiliation(s)
- Asiful Alam
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany.
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24
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Pfohl M, Tune DD, Graf A, Zaumseil J, Krupke R, Flavel BS. Fitting Single-Walled Carbon Nanotube Optical Spectra. ACS Omega 2017; 2:1163-1171. [PMID: 28393134 PMCID: PMC5377271 DOI: 10.1021/acsomega.6b00468] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/09/2017] [Indexed: 05/24/2023]
Abstract
In this work, a comprehensive methodology for the fitting of single-walled carbon nanotube absorption spectra is presented. Different approaches to background subtraction, choice of line profile, and calculation of full width at half-maximum are discussed both in the context of previous literature and the contemporary understanding of carbon nanotube photophysics. The fitting is improved by the inclusion of exciton-phonon sidebands, and new techniques to improve the individualization of overlapped nanotube spectra by exploiting correlations between the first- and second-order optical transitions and the exciton-phonon sidebands are presented. Consideration of metallic nanotubes allows an analysis of the metallic/semiconducting content, and a process of constraining the fit of highly congested spectra of carbon nanotube solid films according to the spectral weights of each (n, m) species in solution is also presented, allowing for more reliable resolution of overlapping peaks into single (n, m) species contributions.
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Affiliation(s)
- Moritz Pfohl
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), P.O.
Box 3640, 76021 Karlsruhe, Germany
- Institute
of Materials Science, Technische Universität
Darmstadt, Jovanka-Bontschits-Str.
2, 64287 Darmstadt, Germany
| | - Daniel D. Tune
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), P.O.
Box 3640, 76021 Karlsruhe, Germany
- Centre
for Nanoscale Science and Technology, Flinders
University, GPO Box 2100, 5042 Adelaide, Australia
| | - Arko Graf
- Institute
for Physical Chemistry, Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Jana Zaumseil
- Institute
for Physical Chemistry, Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Ralph Krupke
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), P.O.
Box 3640, 76021 Karlsruhe, Germany
- Institute
of Materials Science, Technische Universität
Darmstadt, Jovanka-Bontschits-Str.
2, 64287 Darmstadt, Germany
| | - Benjamin S. Flavel
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), P.O.
Box 3640, 76021 Karlsruhe, Germany
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25
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Reis WG, Tomović Ž, Weitz RT, Krupke R, Mikhael J. Wide dynamic range enrichment method of semiconducting single-walled carbon nanotubes with weak field centrifugation. Sci Rep 2017; 7:44812. [PMID: 28317942 PMCID: PMC5357843 DOI: 10.1038/srep44812] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/15/2017] [Indexed: 11/09/2022] Open
Abstract
The potential of single-walled carbon nanotubes (SWCNTs) to outperform silicon in electronic application was finally enabled through selective separation of semiconducting nanotubes from the as-synthesized statistical mix with polymeric dispersants. Such separation methods provide typically high semiconducting purity samples with narrow diameter distribution, i.e. almost single chiralities. But for a wide range of applications high purity mixtures of small and large diameters are sufficient or even required. Here we proof that weak field centrifugation is a diameter independent method for enrichment of semiconducting nanotubes. We show that the non-selective and strong adsorption of polyarylether dispersants on nanostructured carbon surfaces enables simple separation of diverse raw materials with different SWCNT diameter. In addition and for the first time, we demonstrate that increased temperature enables higher purity separation. Furthermore we show that the mode of action behind this electronic enrichment is strongly connected to both colloidal stability and protonation. By giving simple access to electronically sorted SWCNTs of any diameter, the wide dynamic range of weak field centrifugation can provide economical relevance to SWCNTs.
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Affiliation(s)
- Wieland G. Reis
- Carbon Materials Innovation Center (CMIC), BASF SE, 67056 Ludwigshafen, Germany
| | - Željko Tomović
- Carbon Materials Innovation Center (CMIC), BASF SE, 67056 Ludwigshafen, Germany
| | - R. Thomas Weitz
- Physics of Nanosystems, Physics Department, NanoSystems Initiative Munich and Center for NanoScience (CeNS) Ludwig Maximilians Universität München, Amalienstrasse 54, 80799 Munich (Germany)
| | - Ralph Krupke
- Department of Materials and Earth Sciences, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Jules Mikhael
- Material Physics Research, BASF SE, 67056 Ludwigshafen, Germany
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26
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Pyatkov F, Khasminskaya S, Kovalyuk V, Hennrich F, Kappes MM, Goltsman GN, Pernice WHP, Krupke R. Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers. Beilstein J Nanotechnol 2017; 8:38-44. [PMID: 28144563 PMCID: PMC5238692 DOI: 10.3762/bjnano.8.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/20/2016] [Indexed: 05/06/2023]
Abstract
Carbon nanotubes (CNTs) have recently been integrated into optical waveguides and operated as electrically-driven light emitters under constant electrical bias. Such devices are of interest for the conversion of fast electrical signals into optical ones within a nanophotonic circuit. Here, we demonstrate that waveguide-integrated single-walled CNTs are promising high-speed transducers for light-pulse generation in the gigahertz range. Using a scalable fabrication approach we realize hybrid CNT-based nanophotonic devices, which generate optical pulse trains in the range from 200 kHz to 2 GHz with decay times below 80 ps. Our results illustrate the potential of CNTs for hybrid optoelectronic systems and nanoscale on-chip light sources.
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Affiliation(s)
- Felix Pyatkov
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt, Darmstadt 64287, Germany
| | - Svetlana Khasminskaya
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - Vadim Kovalyuk
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
- Department of Physics, Moscow State Pedagogical University, Moscow 119992, Russia
| | - Frank Hennrich
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - Manfred M Kappes
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - Gregory N Goltsman
- Department of Physics, Moscow State Pedagogical University, Moscow 119992, Russia
- National Research University Higher School of Economics, Moscow 101000, Russia
| | | | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt, Darmstadt 64287, Germany
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27
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Li W, Hennrich F, Flavel BS, Kappes MM, Krupke R. Chiral-index resolved length mapping of carbon nanotubes in solution using electric-field induced differential absorption spectroscopy. Nanotechnology 2016; 27:375706. [PMID: 27504810 DOI: 10.1088/0957-4484/27/37/375706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The length of single-walled carbon nanotubes (SWCNTs) is an important metric for the integration of SWCNTs into devices and for the performance of SWCNT-based electronic or optoelectronic applications. In this work we propose a rather simple method based on electric-field induced differential absorption spectroscopy to measure the chiral-index-resolved average length of SWCNTs in dispersions. The method takes advantage of the electric-field induced length-dependent dipole moment of nanotubes and has been verified and calibrated by atomic force microscopy. This method not only provides a low cost, in situ approach for length measurements of SWCNTs in dispersion, but due to the sensitivity of the method to the SWCNT chiral index, the chiral index dependent average length of fractions obtained by chromatographic sorting can also be derived. Also, the determination of the chiral-index resolved length distribution seems to be possible using this method.
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Affiliation(s)
- Wenshan Li
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany. Department of Materials and Earth Sciences, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
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28
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Hennrich F, Li W, Fischer R, Lebedkin S, Krupke R, Kappes MM. Length-Sorted, Large-Diameter, Polyfluorene-Wrapped Semiconducting Single-Walled Carbon Nanotubes for High-Density, Short-Channel Transistors. ACS Nano 2016; 10:1888-95. [PMID: 26792404 DOI: 10.1021/acsnano.5b05572] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Samples of highly enriched semiconducting SWCNTs with average diameters of 1.35 nm have been prepared by combining PODOF polymer wrapping with size-exclusion chromatography. The purity of the material was determined to be >99.7% from the transfer characteristics of short-channel transistors comprising densely aligned sc-SWCNTs. The transistors have a hole mobility of up to 297 cm(2)V(-1) s(-1) and an On/Off ratio as high as 2 × 10(8).
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Affiliation(s)
- Frank Hennrich
- Institute of Nanotechnology, Karlsruhe Institute of Technology , D-76021 Karlsruhe, Germany
| | - Wenshan Li
- Institute of Nanotechnology, Karlsruhe Institute of Technology , D-76021 Karlsruhe, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt , D-64287 Darmstadt, Germany
| | - Regina Fischer
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , D-76128 Karlsruhe, Germany
| | - Sergei Lebedkin
- Institute of Nanotechnology, Karlsruhe Institute of Technology , D-76021 Karlsruhe, Germany
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology , D-76021 Karlsruhe, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt , D-64287 Darmstadt, Germany
| | - Manfred M Kappes
- Institute of Nanotechnology, Karlsruhe Institute of Technology , D-76021 Karlsruhe, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , D-76128 Karlsruhe, Germany
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29
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Fechner RG, Pyatkov F, Khasminskaya S, Flavel BS, Krupke R, Pernice WHP. Directional couplers with integrated carbon nanotube incandescent light emitters. Opt Express 2016; 24:966-74. [PMID: 26832479 DOI: 10.1364/oe.24.000966] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We combine on-chip single-walled carbon nanotubes (SWNTs) emitters with directional coupling devices as fundamental building blocks for carbon photonic systems. These devices are essential for studying the emission properties of SWNTs in the few photon regime for future applications in on-chip quantum photonics. The combination of SWNTs with on-chip beam splitters herein provides the basis for correlation measurements as necessary for nanoscale source characterization. The employed fabrication methods are fully scalable and thus allow for implementing a multitude of functional and active circuits in a single fabrication run. Our metallic SWNT emitters are broadband and cover both visible and near-infrared wavelengths, thus holding promise for emerging hybrid optoelectronic devices with fast reconfiguration times.
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30
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Moore KE, Pfohl M, Tune DD, Hennrich F, Dehm S, Chakradhanula VSK, Kübel C, Krupke R, Flavel BS. Sorting of Double-Walled Carbon Nanotubes According to Their Outer Wall Electronic Type via a Gel Permeation Method. ACS Nano 2015; 9:3849-57. [PMID: 25758564 DOI: 10.1021/nn506869h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In this work, we demonstrate the application of the gel permeation technique to the sorting of double-walled carbon nanotubes (DWCNTs) according to their outer wall electronic type. Our method uses Sephacryl S-200 gel and yields sorted fractions of DWCNTs with impurities removed and highly enriched in nanotubes with either metallic (M) or semiconducting (S) outer walls. The prepared fractions are fully characterized using optical absorption spectroscopy, transmission electron microscopy, and atomic force microscopy, and the entire procedure is monitored in real time using process Raman analysis. The sorted DWCNTs are then integrated into single nanotube field effect transistors, allowing detailed electronic measurement of the transconductance properties of the four unique inner@outer wall combinations of S@S, S@M, M@S, and M@M.
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Affiliation(s)
- Katherine E Moore
- †Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide 5042, Australia
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Moritz Pfohl
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- §Institute for Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Daniel D Tune
- †Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide 5042, Australia
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Frank Hennrich
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Simone Dehm
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Venkata Sai K Chakradhanula
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- ⊥Helmholtz Institute Ulm Electrochemical Energy Storage, 89081 Ulm, Germany
| | - Christian Kübel
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- ⊥Helmholtz Institute Ulm Electrochemical Energy Storage, 89081 Ulm, Germany
- ∥Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Ralph Krupke
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- §Institute for Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Benjamin S Flavel
- ‡Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
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31
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Engel M, Moore KE, Alam A, Dehm S, Krupke R, Flavel BS. Photocurrent spectroscopy of (n, m) sorted solution-processed single-walled carbon nanotubes. ACS Nano 2014; 8:9324-9331. [PMID: 25117458 DOI: 10.1021/nn503278d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Variable-wavelength photocurrent microscopy and photocurrent spectroscopy are used to study the photoresponse of (n, m) sorted single-walled carbon nanotube (SWNT) devices. The measurements of (n, m) pure SWCNT devices demonstrate the ability to study the wavelength-dependent photoresponse in situ in a device configuration and deliver photocurrent spectra that reflect the population of the source material. Furthermore, we show that it is possible to map and determine the chirality population within a working optoelectronic SWCNT device.
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Affiliation(s)
- Michael Engel
- Institute of Nanotechnology, Karlsruhe Institute of Technology , 76021, Karlsruhe, Germany
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32
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Moore KE, Pfohl M, Hennrich F, Chakradhanula VSK, Kuebel C, Kappes MM, Shapter JG, Krupke R, Flavel BS. Separation of double-walled carbon nanotubes by size exclusion column chromatography. ACS Nano 2014; 8:6756-64. [PMID: 24896840 DOI: 10.1021/nn500756a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this report we demonstrate the separation of raw carbon nanotube material into fractions of double-walled (DWCNTs) and single-walled carbon nanotubes (SWCNTs). Our method utilizes size exclusion chromatography with Sephacryl gel S-200 and yielded two distinct fractions of single- and double-walled nanotubes with average diameters of 0.93 ± 0.03 and 1.64 ± 0.15 nm, respectively. The presented technique is easily scalable and offers an alternative to traditional density gradient ultracentrifugation methods. CNT fractions were characterized by atomic force microscopy and Raman and absorption spectroscopy as well as transmission electron microscopy.
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Affiliation(s)
- Katherine E Moore
- Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University , 5000, Adelaide, Australia
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33
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Khasminskaya S, Pyatkov F, Flavel BS, Pernice WH, Krupke R. Waveguide-integrated light-emitting carbon nanotubes. Adv Mater 2014; 26:3465-72. [PMID: 24643956 DOI: 10.1002/adma.201305634] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/10/2014] [Indexed: 05/23/2023]
Abstract
We demonstrate how light from an electrically driven carbon nanotube can be coupled directly into a photonic waveguide architecture. Waferscale, broadband sources are realized integrated with nanophotonic circuits allowing for propagation of light over centimeter distances. Moreover, we show that the spectral properties of the emitter can be controlled directly on chip with passive devices using Mach-Zehnder interfero-meters and grating structures.
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Affiliation(s)
- Svetlana Khasminskaya
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
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34
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Abstract
We demonstrate the upgrade of a commercial confocal Raman microscope into a tip-enhanced Raman microscope/spectroscopy system (TERS) by integrating an interferometrically controlled atomic force microscope into the base of an existing upright microscope to provide near-field detection and thus signal enhancement. The feasibility of the system is demonstrated by measuring the Raman near-field enhancement on thin PEDOT:PSS films and on carbon nanotubes within a device geometry. An enhancement factor of 2-3 and of 5-6 is observed, respectively. Moreover, on a nanotube device we show local conductivity measurement and its correlation to Raman and topography recordings. Upgrading an existing upright confocal Raman microscope in the demonstrated way is significantly cheaper than purchasing a complete commercial TERS system.
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Affiliation(s)
- Matti Oron-Carl
- Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
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35
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Felten A, Eckmann A, Pireaux JJ, Krupke R, Casiraghi C. Controlled modification of mono- and bilayer graphene in O₂, H₂ and CF₄ plasmas. Nanotechnology 2013; 24:355705. [PMID: 23938322 DOI: 10.1088/0957-4484/24/35/355705] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, covalent modification of mono- and bilayer graphene is achieved using tetrafluoromethane (CF₄), oxygen and hydrogen RF plasma. Controlled modification of graphene is usually difficult to achieve, in particular with oxygen plasma, which is rather aggressive and usually leads to etching of graphene. Here we use x-ray photoelectron spectroscopy and Raman spectroscopy to show that mild plasma conditions and fine tuning of the number of functional groups can be obtained in all plasmas by varying parameters such as exposure time and sample position inside the chamber. We found that even for the usual harsh oxygen treatment the defect density could be lowered, down to one defect for 3.5 × 10⁴ carbon atoms. Furthermore, we show that CF₄ plasma leads to functionalization without etching and that graphene becomes an insulator at saturation coverage. In addition, the reactivity of mono- and bilayer graphene was studied revealing faster modification of monolayer in oxygen and CF₄ plasma, in agreement with previous works. In contrast, similar modification rates were observed for both mono- and bilayer during hydrogenation. We attribute this discrepancy to the presence of more energetic species in the hydrogen plasma such as positive ions that could play a role in the functionalization process.
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Affiliation(s)
- A Felten
- Research Center in Physics of Matter and Radiation-PMR, University of Namur, B-5000 Namur, Belgium.
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36
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Lukas M, Meded V, Vijayaraghavan A, Song L, Ajayan PM, Fink K, Wenzel W, Krupke R. Catalytic subsurface etching of nanoscale channels in graphite. Nat Commun 2013; 4:1379. [PMID: 23340419 DOI: 10.1038/ncomms2399] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 12/19/2012] [Indexed: 11/09/2022] Open
Abstract
Catalytic hydrogenation of graphite has recently attracted renewed attention as a route for nanopatterning of graphene and to produce graphene nanoribbons. These reports show that metallic nanoparticles etch the surface layers of graphite or graphene anisotropically along the crystallographic zig-zag ‹11-20› or armchair ‹10-10› directions. The etching direction can be influenced by external magnetic fields or the supporting substrate. Here we report the subsurface etching of highly oriented pyrolytic graphite by Ni nanoparticles, to form a network of tunnels, as seen by scanning electron microscopy and scanning tunnelling microscopy. In this new nanoporous form of graphite, the top layers bend inward on top of the tunnels, whereas their local density of states remains fundamentally unchanged. Engineered nanoporous tunnel networks in graphite allow for further chemical modification and may find applications in various fields and in fundamental science research.
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Affiliation(s)
- Maya Lukas
- Karlsruhe Institute of Technology, Institute of Nanotechnology, D-76021 Karlsruhe, Germany.
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37
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Lukas M, Meded V, Vijayaraghavan A, Song L, Ajayan PM, Fink K, Wenzel W, Krupke R. Erratum: Corrigendum: Catalytic subsurface etching of nanoscale channels in graphite. Nat Commun 2013. [DOI: 10.1038/ncomms2732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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38
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Flavel BS, Kappes MM, Krupke R, Hennrich F. Separation of single-walled carbon nanotubes by 1-dodecanol-mediated size-exclusion chromatography. ACS Nano 2013; 7:3557-64. [PMID: 23540203 DOI: 10.1021/nn4004956] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A simple, single-column, high-throughput fractionation procedure based on size-exclusion chromatography of aqueous sodium dodecyl sulfate suspensions of single-walled carbon nanotubes (SWCNTs) is presented. This procedure is found to yield monochiral or near monochiral SWCNT fractions of semiconducting SWCNTs. Unsorted and resulting monochiral suspensions are characterized using optical absorption and photoluminescence spectroscopy.
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Affiliation(s)
- Benjamin S Flavel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.
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39
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Abstract
We detect electroluminescence in single layer molybdenum disulfide (MoS2) field-effect transistors built on transparent glass substrates. By comparing the absorption, photoluminescence, and electroluminescence of the same MoS2 layer, we find that they all involve the same excited state at 1.8 eV. The electroluminescence has pronounced threshold behavior and is localized at the contacts. The results show that single layer MoS2, a direct band gap semiconductor, could be promising for novel optoelectronic devices, such as two-dimensional light detectors and emitters.
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Affiliation(s)
- R S Sundaram
- Cambridge Graphene Centre, University of Cambridge, Cambridge, United Kingdom
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40
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Felten A, Flavel BS, Britnell L, Eckmann A, Louette P, Pireaux JJ, Hirtz M, Krupke R, Casiraghi C. Single- and double-sided chemical functionalization of bilayer graphene. Small 2013; 9:631-639. [PMID: 23166066 DOI: 10.1002/smll.201202214] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 06/01/2023]
Abstract
An experimental study on the interaction between the top and bottom layer of a chemically functionalized graphene bilayer by mild oxygen plasma is reported. Structural, chemical, and electrical properties are monitored using Raman spectroscopy, transport measurements, conductive atomic force microscopy and X-ray photoelectron spectroscopy. Single- and double-sided chemical functionalization are found to give very different results: single-sided modified bilayers show relatively high mobility (200-600 cm(2) V(-1) s(-1) at room temperature) and a stable structure with a limited amount of defects, even after long plasma treatment (>60 s). This is attributed to preferential modification and limited coverage of the top layer during plasma exposure, while the bottom layer remains almost unperturbed. This could eventually lead to decoupling between top and bottom layers. Double-sided chemical functionalization leads to a structure containing a high concentration of defects, very similar to graphene oxide. This opens the possibility to use plasma treatment not only for etching and patterning of graphene, but also to make heterostructures (through single-sided modification of bilayers) for sensors and transistors and new graphene-derivatives materials (through double-sided modification).
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41
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Engel M, Steiner M, Sundaram RS, Krupke R, Green AA, Hersam MC, Avouris P. Spatially resolved electrostatic potential and photocurrent generation in carbon nanotube array devices. ACS Nano 2012; 6:7303-7310. [PMID: 22769018 DOI: 10.1021/nn302416e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have used laser-excited photocurrent microscopy to map the internal electrostatic potential profile of semiconducting single-walled carbon nanotube (S-SWCNT) array devices with a spatial resolution of 250 nm. The measurements of S-SWCNTs on optically transparent samples provide new insights into the physical principles of device operation and reveal performance-limiting local heterogeneities in the electrostatic potential profile not observable with other imaging techniques. The experiments deliver photocurrent images from the underside of the S-SWCNT-metal contacts and thus enable the direct measurement of the charge carrier transfer lengths at the palladium-S-SWCNT and aluminum-S-SWCNT interfaces. We use the experimental results to formulate design rules for optimized layouts of S-SWCNT-based photovoltaic devices. Furthermore, we demonstrate the external control of the electrostatic potential profile in S-SWCNT array devices equipped with local metal gates.
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Affiliation(s)
- Michael Engel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
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42
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Eckmann A, Felten A, Mishchenko A, Britnell L, Krupke R, Novoselov KS, Casiraghi C. Probing the nature of defects in graphene by Raman spectroscopy. Nano Lett 2012; 12:3925-30. [PMID: 22764888 DOI: 10.1021/nl300901a] [Citation(s) in RCA: 614] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Raman spectroscopy is able to probe disorder in graphene through defect-activated peaks. It is of great interest to link these features to the nature of disorder. Here we present a detailed analysis of the Raman spectra of graphene containing different type of defects. We found that the intensity ratio of the D and D' peak is maximum (∼13) for sp(3)-defects, it decreases for vacancy-like defects (∼7), and it reaches a minimum for boundaries in graphite (∼3.5). This makes Raman Spectroscopy a powerful tool to fully characterize graphene.
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Affiliation(s)
- Axel Eckmann
- School of Chemistry and Photon Science Institute, University of Manchester, United Kingdom
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43
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Rauhut N, Engel M, Steiner M, Krupke R, Avouris P, Hartschuh A. Antenna-enhanced photocurrent microscopy on single-walled carbon nanotubes at 30 nm resolution. ACS Nano 2012; 6:6416-21. [PMID: 22632038 PMCID: PMC3807727 DOI: 10.1021/nn301979c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We present the first photocurrent measurements along single carbon nanotube (CNT) devices with 30 nm resolution. Our technique is based on tip-enhanced near-field optical microscopy, exploiting the plasmonically enhanced absorption controlled by an optical nanoantenna. This allows for imaging of the zero-bias photocurrent caused by charge separation in local built-in electric fields at the contacts and close to charged particles that cannot be resolved using confocal microscopy. Simultaneously recorded Raman scattering images reveal the structural properties and the defect densities of the CNTs. Antenna-enhanced scanning photocurrent microscopy extends the available set of scanning-probe techniques by combining high-resolution photovoltaic and optical probing and could become a valuable tool for the characterization of nanoelectronic devices.
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Affiliation(s)
- Nina Rauhut
- Department Chemie and CeNS, Ludwig-Maximilians-Universität, 81377 Munich, Germany
| | - Michael Engel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- DFG Center for Functional Nanostructures (CFN), 76031 Karlsruhe, Germany
| | - Mathias Steiner
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- DFG Center for Functional Nanostructures (CFN), 76031 Karlsruhe, Germany
- Institut für Materialwissenschaft, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Phaedon Avouris
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Achim Hartschuh
- Department Chemie and CeNS, Ludwig-Maximilians-Universität, 81377 Munich, Germany
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44
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Engel M, Steiner M, Lombardo A, Ferrari AC, Löhneysen HV, Avouris P, Krupke R. Light-matter interaction in a microcavity-controlled graphene transistor. Nat Commun 2012; 3:906. [PMID: 22713748 PMCID: PMC3621428 DOI: 10.1038/ncomms1911] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/16/2012] [Indexed: 12/22/2022] Open
Abstract
Graphene has extraordinary electronic and optical properties and holds great promise for applications in photonics and optoelectronics. Demonstrations including high-speed photodetectors, optical modulators, plasmonic devices, and ultrafast lasers have now been reported. More advanced device concepts would involve photonic elements such as cavities to control light-matter interaction in graphene. Here we report the first monolithic integration of a graphene transistor and a planar, optical microcavity. We find that the microcavity-induced optical confinement controls the efficiency and spectral selection of photocurrent generation in the integrated graphene device. A twenty-fold enhancement of photocurrent is demonstrated. The optical cavity also determines the spectral properties of the electrically excited thermal radiation of graphene. Most interestingly, we find that the cavity confinement modifies the electrical transport characteristics of the integrated graphene transistor. Our experimental approach opens up a route towards cavity-quantum electrodynamics on the nanometre scale with graphene as a current-carrying intra-cavity medium of atomic thickness.
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Affiliation(s)
- Michael Engel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- DFG Center for Functional Nanostructures (CFN), 76031 Karlsruhe, Germany
| | - Mathias Steiner
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Antonio Lombardo
- Engineering Department, University of Cambridge, Cambridge CB3 0FA, UK
| | - Andrea C. Ferrari
- Engineering Department, University of Cambridge, Cambridge CB3 0FA, UK
| | - Hilbert v. Löhneysen
- DFG Center for Functional Nanostructures (CFN), 76031 Karlsruhe, Germany
- Physics Institute, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute of Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Phaedon Avouris
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Ralph Krupke
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- DFG Center for Functional Nanostructures (CFN), 76031 Karlsruhe, Germany
- Department of Materials and Earth Sciences, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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45
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Ding C, Tian C, Krupke R, Fang J. Growth of non-branching Ag nanowiresvia ion migrational-transport controlled 3D electrodeposition. CrystEngComm 2012. [DOI: 10.1039/c1ce05686g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Chappaz-Gillot C, Marek PL, Blaive BJ, Canard G, Bürck J, Garab G, Hahn H, Jávorfi T, Kelemen L, Krupke R, Mössinger D, Ormos P, Reddy CM, Roussel C, Steinbach G, Szabó M, Ulrich AS, Vanthuyne N, Vijayaraghavan A, Zupcanova A, Balaban TS. Anisotropic organization and microscopic manipulation of self-assembling synthetic porphyrin microrods that mimic chlorosomes: bacterial light-harvesting systems. J Am Chem Soc 2011; 134:944-54. [PMID: 22148684 DOI: 10.1021/ja203838p] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Being able to control in time and space the positioning, orientation, movement, and sense of rotation of nano- to microscale objects is currently an active research area in nanoscience, having diverse nanotechnological applications. In this paper, we demonstrate unprecedented control and maneuvering of rod-shaped or tubular nanostructures with high aspect ratios which are formed by self-assembling synthetic porphyrins. The self-assembly algorithm, encoded by appended chemical-recognition groups on the periphery of these porphyrins, is the same as the one operating for chlorosomal bacteriochlorophylls (BChl's). Chlorosomes, rod-shaped organelles with relatively long-range molecular order, are the most efficient naturally occurring light-harvesting systems. They are used by green photosynthetic bacteria to trap visible and infrared light of minute intensities even at great depths, e.g., 100 m below water surface or in volcanic vents in the absence of solar radiation. In contrast to most other natural light-harvesting systems, the chlorosomal antennae are devoid of a protein scaffold to orient the BChl's; thus, they are an attractive goal for mimicry by synthetic chemists, who are able to engineer more robust chromophores to self-assemble. Functional devices with environmentally friendly chromophores-which should be able to act as photosensitizers within hybrid solar cells, leading to high photon-to-current conversion efficiencies even under low illumination conditions-have yet to be fabricated. The orderly manner in which the BChl's and their synthetic counterparts self-assemble imparts strong diamagnetic and optical anisotropies and flow/shear characteristics to their nanostructured assemblies, allowing them to be manipulated by electrical, magnetic, or tribomechanical forces.
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Affiliation(s)
- Cyril Chappaz-Gillot
- ISM2-Chirosciences, Faculté des Sciences, Aix-Marseille Univ. UMR 6263, Saint-Jérôme, Case A62, Avenue Escadrille Normandie-Niemen, F-13397 Marseille, Cedex 20, France
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47
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Pfeiffer MHP, Stürzl N, Marquardt CW, Engel M, Dehm S, Hennrich F, Kappes MM, Lemmer U, Krupke R. Electroluminescence from chirality-sorted (9,7)-semiconducting carbon nanotube devices. Opt Express 2011; 19 Suppl 6:A1184-A1189. [PMID: 22109613 DOI: 10.1364/oe.19.0a1184] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have measured the electroluminescence and photoluminescence of (9,7)-semiconducting carbon nanotube devices and demonstrate that the electroluminescence wavelength is determined by the nanotube's chiral index (n,m). The devices were fabricated on Si₃N₄-membranes by dielectrophoretic assembly of tubes from monochiral dispersion. Electrically driven (9,7)-devices exhibit a single Lorentzian-shaped emission peak at 825 nm in the visible part of the spectrum. The emission could be assigned to the excitonic E22 interband-transition by comparison of the electroluminescence spectra with corresponding photoluminescence excitation maps. We show a linear dependence of the EL peak width on the electrical current, and provide evidence for the inertness of Si₃N₄ surfaces with respect to the nanotubes optical properties.
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Affiliation(s)
- Martin H P Pfeiffer
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
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48
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Sundaram RS, Steiner M, Chiu HY, Engel M, Bol AA, Krupke R, Burghard M, Kern K, Avouris P. The graphene-gold interface and its implications for nanoelectronics. Nano Lett 2011; 11:3833-7. [PMID: 21809874 DOI: 10.1021/nl201907u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We combine optical microspectroscopy and electronic measurements to study how gold deposition affects the physical properties of graphene. We find that the electronic structure, the electron-phonon coupling, and the doping level in gold-plated graphene are largely preserved. The transfer lengths for electrons and holes at the graphene-gold contact have values as high as 1.6 μm. However, the interfacial coupling of graphene and gold causes local temperature drops of up to 500 K in operating electronic devices.
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Affiliation(s)
- Ravi S Sundaram
- Max-Planck-Institute for Solid State Research, 70569 Stuttgart, Germany
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49
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Vijayaraghavan A, Timmermans MY, Grigoras K, Nasibulin AG, Kauppinen EI, Krupke R. Imaging conduction pathways in carbon nanotube network transistors by voltage-contrast scanning electron microscopy. Nanotechnology 2011; 22:265715. [PMID: 21586812 DOI: 10.1088/0957-4484/22/26/265715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The performance of field-effect transistors based on single-walled carbon nanotube (SWCNT) networks depends on the electrical percolation of semiconducting and metallic nanotube pathways within the network. We present voltage-contrast scanning electron microscopy (VC-SEM) as a new tool for imaging percolation in a SWCNT network with nano-scale resolution. Under external bias, the secondary-electron contrast of SWCNTs depends on their conductivity, and therefore it is possible to image the preferred conduction pathways within a network by following the contrast evolution under bias in a scanning electron microscope. The experimental VC-SEM results are correlated to percolation models of SWCNT-bundle networks.
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50
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Ganzhorn M, Vijayaraghavan A, Green AA, Dehm S, Voigt A, Rapp M, Hersam MC, Krupke R. A scalable, CMOS-compatible assembly of ambipolar semiconducting single-walled carbon nanotube devices. Adv Mater 2011; 23:1734-1738. [PMID: 21491506 DOI: 10.1002/adma.201004640] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Marc Ganzhorn
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Germany
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