1
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Dockx K, Barnes MD, Wehenkel DJ, van Rijn R, van der Zant HSJ, Buscema M. Strong doping reduction on wafer-scale CVD graphene devices via Al 2O 3ALD encapsulation. NANOTECHNOLOGY 2024; 35:395202. [PMID: 38955146 DOI: 10.1088/1361-6528/ad5dbb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 07/02/2024] [Indexed: 07/04/2024]
Abstract
We present the electrical characterization of wafer-scale graphene devices fabricated with an industrially-relevant, contact-first integration scheme combined with Al2O3encapsulation via atomic layer deposition. All the devices show a statistically significant reduction in the Dirac point position,Vcnp, from around +47 V to between -5 and 5 V (on 285 nm SiO2), while maintaining the mobility values. The data and methods presented are relevant for further integration of graphene devices, specifically sensors, at the back-end-of-line of a standard CMOS flow.
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Affiliation(s)
- K Dockx
- Applied Nanolayers B.V., Feldmannweg 17, 2628 CT Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - M D Barnes
- Applied Nanolayers B.V., Feldmannweg 17, 2628 CT Delft, The Netherlands
| | - D J Wehenkel
- Applied Nanolayers B.V., Feldmannweg 17, 2628 CT Delft, The Netherlands
| | - R van Rijn
- Applied Nanolayers B.V., Feldmannweg 17, 2628 CT Delft, The Netherlands
| | - H S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - M Buscema
- Applied Nanolayers B.V., Feldmannweg 17, 2628 CT Delft, The Netherlands
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2
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Nashashibi S, Koepfli SM, Schwanninger R, Baumann M, Doderer M, Bisang D, Fedoryshyn Y, Leuthold J. Engineering Graphene Phototransistors for High Dynamic Range Applications. ACS NANO 2024; 18:12760-12770. [PMID: 38728257 PMCID: PMC11112981 DOI: 10.1021/acsnano.3c11856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/23/2024] [Accepted: 05/01/2024] [Indexed: 05/12/2024]
Abstract
Phototransistors are light-sensitive devices featuring a high dynamic range, low-light detection, and mechanisms to adapt to different ambient light conditions. These features are of interest for bioinspired applications such as artificial and restored vision. In this work, we report on a graphene-based phototransistor exploiting the photogating effect that features picowatt- to microwatt-level photodetection, a dynamic range covering six orders of magnitude from 7 to 107 lux, and a responsivity of up to 4.7 × 103 A/W. The proposed device offers the highest dynamic range and lowest optical power detected compared to the state of the art in interfacial photogating and further operates air stably. These results have been achieved by a combination of multiple developments. For example, by optimizing the geometry of our devices with respect to the graphene channel aspect ratio and by introducing a semitransparent top-gate electrode, we report a factor 20-30 improvement in responsivity over unoptimized reference devices. Furthermore, we use a built-in dynamic range compression based on a partial logarithmic optical power dependence in combination with control of responsivity. These features enable adaptation to changing lighting conditions and support high dynamic range operation, similar to what is known in human visual perception. The enhanced performance of our devices therefore holds potential for bioinspired applications, such as retinal implants.
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Affiliation(s)
- Shadi Nashashibi
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | - Stefan M. Koepfli
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | | | - Michael Baumann
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | - Michael Doderer
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | - Dominik Bisang
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | - Yuriy Fedoryshyn
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
| | - Juerg Leuthold
- ETH Zurich, Institute of
Electromagnetic Fields, Zurich 8092, Switzerland
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3
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Koepfli SM, Baumann M, Koyaz Y, Gadola R, Güngör A, Keller K, Horst Y, Nashashibi S, Schwanninger R, Doderer M, Passerini E, Fedoryshyn Y, Leuthold J. Metamaterial graphene photodetector with bandwidth exceeding 500 gigahertz. Science 2023; 380:1169-1174. [PMID: 37319195 DOI: 10.1126/science.adg8017] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/11/2023] [Indexed: 06/17/2023]
Abstract
Although graphene has met many of its initially predicted optoelectronic, thermal, and mechanical properties, photodetectors with large spectral bandwidths and extremely high frequency responses remain outstanding. In this work, we demonstrate a >500 gigahertz, flat-frequency response, graphene-based photodetector that operates under ambient conditions across a 200-nanometer-wide spectral band with center wavelengths adaptable from <1400 to >4200 nanometers. Our detector combines graphene with metamaterial perfect absorbers with direct illumination from a single-mode fiber, which breaks with the conventional miniaturization of photodetectors on an integrated photonic platform. This design allows for much higher optical powers while still allowing record-high bandwidths and data rates. Our results demonstrate that graphene photodetectors can outperform conventional technologies in terms of speed, bandwidth, and operation across a large spectral range.
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Affiliation(s)
- Stefan M Koepfli
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Michael Baumann
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Yesim Koyaz
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Robin Gadola
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Arif Güngör
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Killian Keller
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Yannik Horst
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Shadi Nashashibi
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | | | - Michael Doderer
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Elias Passerini
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Yuriy Fedoryshyn
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
| | - Juerg Leuthold
- Institute of Electromagnetic Fields (IEF), ETH Zürich, 8092 Zürich, Switzerland
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4
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Trasobares J, Martín-Romano JC, Khaliq MW, Ruiz-Gómez S, Foerster M, Niño MÁ, Pedraz P, Dappe YJ, de Ory MC, García-Pérez J, Acebrón M, Osorio MR, Magaz MT, Gomez A, Miranda R, Granados D. Hybrid molecular graphene transistor as an operando and optoelectronic platform. Nat Commun 2023; 14:1381. [PMID: 36914623 PMCID: PMC10011542 DOI: 10.1038/s41467-023-36714-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/13/2023] [Indexed: 03/16/2023] Open
Abstract
Lack of reproducibility hampers molecular devices integration into large-scale circuits. Thus, incorporating operando characterization can facilitate the understanding of multiple features producing disparities in different devices. In this work, we report the realization of hybrid molecular graphene field effect transistors (m-GFETs) based on 11-(Ferrocenyl)undecanethiol (FcC11SH) micro self-assembled monolayers (μSAMs) and high-quality graphene (Gr) in a back-gated configuration. On the one hand, Gr enables redox electron transfer, avoids molecular degradation and permits operando spectroscopy. On the other hand, molecular electrode decoration shifts the Gr Dirac point (VDP) to neutrality and generates a photocurrent in the Gr electron conduction regime. Benefitting from this heterogeneous response, the m-GFETs can implement optoelectronic AND/OR logic functions. Our approach represents a step forward in the field of molecular scale electronics with implications in sensing and computing based on sustainable chemicals.
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Affiliation(s)
- Jorge Trasobares
- IMDEA-Nanociencia, Cantoblanco, Madrid, 28049, Spain. .,Department of Biodiversity, Ecology and Evolution (Biomathematics), Universidad Complutense de Madrid, Madrid, 28040, Spain.
| | | | - Muhammad Waqas Khaliq
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain.,Department of Condensed Matter Physics, University of Barcelona, Barcelona, Spain
| | - Sandra Ruiz-Gómez
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | - Michael Foerster
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | - Miguel Ángel Niño
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | | | - Yannick J Dappe
- Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, 28850, Spain
| | | | | | - María Acebrón
- IMDEA-Nanociencia, Cantoblanco, Madrid, 28049, Spain
| | | | | | - Alicia Gomez
- Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, 28850, Spain
| | - Rodolfo Miranda
- SPEC, CEA, CNRS Université Paris-Saclay, Gif-sur-Yvette, 91191, France.,Dpto. de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Spain
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5
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Pasadas F, Feijoo PC, Mavredakis N, Pacheco-Sanchez A, Chaves FA, Jiménez D. Compact Modeling Technology for the Simulation of Integrated Circuits Based on Graphene Field-Effect Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201691. [PMID: 35593428 DOI: 10.1002/adma.202201691] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/26/2022] [Indexed: 06/15/2023]
Abstract
The progress made toward the definition of a modular compact modeling technology for graphene field-effect transistors (GFETs) that enables the electrical analysis of arbitrary GFET-based integrated circuits is reported. A set of primary models embracing the main physical principles defines the ideal GFET response under DC, transient (time domain), AC (frequency domain), and noise (frequency domain) analysis. Another set of secondary models accounts for the GFET non-idealities, such as extrinsic-, short-channel-, trapping/detrapping-, self-heating-, and non-quasi static-effects, which can have a significant impact under static and/or dynamic operation. At both device and circuit levels, significant consistency is demonstrated between the simulation output and experimental data for relevant operating conditions. Additionally, a perspective of the challenges during the scale up of the GFET modeling technology toward higher technology readiness levels while drawing a collaborative scenario among fabrication technology groups, modeling groups, and circuit designers, is provided.
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Affiliation(s)
- Francisco Pasadas
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
- Departamento de Electrónica y Tecnología de Computadores, Universidad de Granada, Granada, 18071, Spain
| | - Pedro C Feijoo
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Nikolaos Mavredakis
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Aníbal Pacheco-Sanchez
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Ferney A Chaves
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - David Jiménez
- Departament d'Enginyeria Electrònica, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
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6
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Graphene-Based Temperature Sensors–Comparison of the Temperature and Humidity Dependences. NANOMATERIALS 2022; 12:nano12091594. [PMID: 35564303 PMCID: PMC9102891 DOI: 10.3390/nano12091594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022]
Abstract
Four different graphene-based temperature sensors were prepared, and their temperature and humidity dependences were tested. Sensor active layers prepared from reduced graphene oxide (rGO) and graphene nanoplatelets (Gnp) were deposited on the substrate from a dispersion by air brush spray coating. Another sensor layer was made by graphene growth from a plasma discharge (Gpl). The last graphene layer was prepared by chemical vapor deposition (Gcvd) and then transferred onto the substrate. The structures of rGO, Gnp, and Gpl were studied by scanning electron microscopy. The obtained results confirmed the different structures of these materials. Energy-dispersive X-ray diffraction was used to determine the elemental composition of the materials. Gcvd was characterized by X-ray photoelectron spectroscopy. Elemental analysis showed different oxygen contents in the structures of the materials. Sensors with a small flake structure, i.e., rGO and Gnp, showed the highest change in resistance as a function of temperature. The temperature coefficient of resistance was 5.16−3·K−1 for Gnp and 4.86−3·K−1 for rGO. These values exceed that for a standard platinum thermistor. The Gpl and Gcvd sensors showed the least dependence on relative humidity, which is attributable to the number of oxygen groups in their structures.
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7
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Lu YX, Lin CT, Tsai MH, Lin KC. Review-Hysteresis in Carbon Nano-Structure Field Effect Transistor. MICROMACHINES 2022; 13:mi13040509. [PMID: 35457813 PMCID: PMC9029578 DOI: 10.3390/mi13040509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/18/2022] [Accepted: 03/22/2022] [Indexed: 11/16/2022]
Abstract
In recent decades, the research of nano-structure devices (e.g., carbon nanotube and graphene) has experienced rapid growth. These materials have supreme electronic, thermal, optical and mechanical properties and have received widespread concern in different fields. It is worth noting that gate hysteresis behavior of field effect transistors can always be found in ambient conditions, which may influence the transmission appearance. Many researchers have put forward various views on this question. Here, we summarize and discuss the mechanisms behind hysteresis, different influencing factors and improvement methods which help decrease or eliminate unevenness and asymmetry.
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8
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Tyagi A, Mišeikis V, Martini L, Forti S, Mishra N, Gebeyehu ZM, Giambra MA, Zribi J, Frégnaux M, Aureau D, Romagnoli M, Beltram F, Coletti C. Ultra-clean high-mobility graphene on technologically relevant substrates. NANOSCALE 2022; 14:2167-2176. [PMID: 35080556 DOI: 10.1039/d1nr05904a] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Graphene grown via chemical vapour deposition (CVD) on copper foil has emerged as a high-quality, scalable material, that can be easily integrated on technologically relevant platforms to develop promising applications in the fields of optoelectronics and photonics. Most of these applications require low-contaminated high-mobility graphene (i.e., approaching 10 000 cm2 V-1 s-1 at room temperature) to reduce device losses and implement compact device design. To date, these mobility values are only obtained when suspending or encapsulating graphene. Here, we demonstrate a rapid, facile, and scalable cleaning process, that yields high-mobility graphene directly on the most common technologically relevant substrate: silicon dioxide on silicon (SiO2/Si). Atomic force microscopy (AFM) and spatially-resolved X-ray photoelectron spectroscopy (XPS) demonstrate that this approach is instrumental to rapidly eliminate most of the polymeric residues which remain on graphene after transfer and fabrication and that have adverse effects on its electrical properties. Raman measurements show a significant reduction of graphene doping and strain. Transport measurements of 50 Hall bars (HBs) yield hole mobility μh up to ∼9000 cm2 V-1 s-1 and electron mobility μe up to ∼8000 cm2 V-1 s-1, with average values μh ∼ 7500 cm2 V-1 s-1 and μe ∼ 6300 cm2 V-1 s-1. The carrier mobility of ultraclean graphene reaches values nearly double than those measured in graphene processed with acetone cleaning, which is the method widely adopted in the field. Notably, these mobility values are obtained over large-scale and without encapsulation, thus paving the way to the adoption of graphene in optoelectronics and photonics.
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Affiliation(s)
- Ayush Tyagi
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
| | - Vaidotas Mišeikis
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Leonardo Martini
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
| | - Stiven Forti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
| | - Neeraj Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Zewdu M Gebeyehu
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | | | - Jihene Zribi
- Institut Lavoisier de Versailles UMR 8180 Université Paris-Saclay, UVSQ, CNRS, 78035 Versailles, France
| | - Mathieu Frégnaux
- Institut Lavoisier de Versailles UMR 8180 Université Paris-Saclay, UVSQ, CNRS, 78035 Versailles, France
| | - Damien Aureau
- Institut Lavoisier de Versailles UMR 8180 Université Paris-Saclay, UVSQ, CNRS, 78035 Versailles, France
| | - Marco Romagnoli
- Photonic Networks and Technologies Lab, CNIT, 56124 Pisa, Italy
| | - Fabio Beltram
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Camilla Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Technologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
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9
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Ali MM, Mitchell JJ, Burwell G, Rejnhard K, Jenkins CA, Daghigh Ahmadi E, Sharma S, Guy OJ. Application of Molecular Vapour Deposited Al 2O 3 for Graphene-Based Biosensor Passivation and Improvements in Graphene Device Homogeneity. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2121. [PMID: 34443952 PMCID: PMC8398646 DOI: 10.3390/nano11082121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022]
Abstract
Graphene-based point-of-care (PoC) and chemical sensors can be fabricated using photolithographic processes at wafer-scale. However, these approaches are known to leave polymer residues on the graphene surface, which are difficult to remove completely. In addition, graphene growth and transfer processes can introduce defects into the graphene layer. Both defects and resist contamination can affect the homogeneity of graphene-based PoC sensors, leading to inconsistent device performance and unreliable sensing. Sensor reliability is also affected by the harsh chemical environments used for chemical functionalisation of graphene PoC sensors, which can degrade parts of the sensor device. Therefore, a reliable, wafer-scale method of passivation, which isolates the graphene from the rest of the device, protecting the less robust device features from any aggressive chemicals, must be devised. This work covers the application of molecular vapour deposition technology to create a dielectric passivation film that protects graphene-based biosensing devices from harsh chemicals. We utilise a previously reported "healing effect" of Al2O3 on graphene to reduce photoresist residue from the graphene surface and reduce the prevalence of graphene defects to improve graphene device homogeneity. The improvement in device consistency allows for more reliable, homogeneous graphene devices, that can be fabricated at wafer-scale for sensing and biosensing applications.
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Affiliation(s)
- Muhammad Munem Ali
- Centre for NanoHealth, College of Engineering, Swansea University, Swansea SA2 8PP, UK; (J.J.M.); (E.D.A.)
| | - Jacob John Mitchell
- Centre for NanoHealth, College of Engineering, Swansea University, Swansea SA2 8PP, UK; (J.J.M.); (E.D.A.)
| | - Gregory Burwell
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK; (G.B.); (K.R.)
| | - Klaudia Rejnhard
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK; (G.B.); (K.R.)
| | | | - Ehsaneh Daghigh Ahmadi
- Centre for NanoHealth, College of Engineering, Swansea University, Swansea SA2 8PP, UK; (J.J.M.); (E.D.A.)
| | - Sanjiv Sharma
- Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea SA1 8EN, UK;
| | - Owen James Guy
- Centre for NanoHealth, College of Engineering, Swansea University, Swansea SA2 8PP, UK; (J.J.M.); (E.D.A.)
- Department of Chemistry, College of Science, Swansea University, Swansea SA2 8PP, UK
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10
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Epitaxial Graphene on 4H-SiC (0001) as a Versatile Platform for Materials Growth: Mini-Review. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11135784] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Material growth on a dangling-bond-free interface such as graphene is a challenging technological task, which usually requires additional surface pre-treatment steps (functionalization, seed layer formation) to provide enough reactive sites. Being one of the most promising and adaptable graphene-family materials, epitaxial graphene on SiC, due to its internal features (substrate-induced n-doping, compressive strain, terrace-stepped morphology, bilayer graphene nano-inclusions), may provide pre-conditions for the enhanced binding affinity of environmental species, precursor molecules, and metal atoms on the topmost graphene layer. It makes it possible to use untreated pristine epitaxial graphene as a versatile platform for the deposition of metals and insulators. This mini-review encompasses relevant aspects of magnetron sputtering and electrodeposition of selected metals (Au, Ag, Pb, Hg, Cu, Li) and atomic layer deposition of insulating Al2O3 layers on epitaxial graphene on 4H-SiC, focusing on understanding growth mechanisms. Special deliberation has been given to the effect of the deposited materials on the epitaxial graphene quality. The generalization of the experimental and theoretical results presented here is hopefully an important step towards new electronic devices (chemiresistors, Schottky diodes, field-effect transistors) for environmental sensing, nano-plasmonics, and biomedical applications.
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11
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Ramadan S, Zhang Y, Tsang DKH, Shaforost O, Xu L, Bower R, Dunlop IE, Petrov PK, Klein N. Enhancing Structural Properties and Performance of Graphene-Based Devices Using Self-Assembled HMDS Monolayers. ACS OMEGA 2021; 6:4767-4775. [PMID: 33644584 PMCID: PMC7905810 DOI: 10.1021/acsomega.0c05631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
The performance of graphene devices is often limited by defects and impurities induced during device fabrication. Polymer residue left on the surface of graphene after photoresist processing can increase electron scattering and hinder electron transport. Furthermore, exposing graphene to plasma-based processing such as sputtering of metallization layers can increase the defect density in graphene and alter the device performance. Therefore, the preservation of the high-quality surface of graphene during thin-film deposition and device manufacturing is essential for many electronic applications. Here, we show that the use of self-assembled monolayers (SAMs) of hexamethyldisilazane (HMDS) as a buffer layer during the device fabrication of graphene can significantly reduce damage, improve the quality of graphene, and enhance device performance. The role of HMDS has been systematically investigated using surface analysis techniques and electrical measurements. The benefits of HMDS treatment include a significant reduction in defect density compared with as-treated graphene and more than a 2-fold reduction of contact resistance. This surface treatment is simple and offers a practical route for improving graphene device interfaces, which is important for the integration of graphene into functional devices such as electronics and sensor devices.
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12
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Alessandri C, Asselberghs I, Brems S, Huyghebaert C, Van Campenhout J, Van Thourhout D, Pantouvaki M. 5 × 25 Gbit/s WDM transmitters based on passivated graphene-silicon electro-absorption modulators. APPLIED OPTICS 2020; 59:1156-1162. [PMID: 32225255 DOI: 10.1364/ao.383462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Today, one of the key challenges of graphene devices is establishing fabrication processes that can ensure performance stability and repeatability and that can eventually enable production in high volumes. In this paper, we use up-scalable fabrication processes to demonstrate three five-channel wavelength-division multiplexing (WDM) transmitters, each based on five graphene-silicon electro-absorption modulators. A passivation-first approach is used to encapsulate graphene, which results in hysteresis-free and uniform performance across the five channels of each WDM transmitter, for a total of 15 modulators. Open-eye diagrams are obtained at 25 Gb/s using $ 2.5\;{{\rm V}_{{\rm pp}}} $2.5Vpp, thus demonstrating potential for multi-channel data transmission at ${5}\times {25}\;{\rm Gb/s}$5×25Gb/s on each of the three WDM transmitters.
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13
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Son M, Kim H, Jang J, Kim SY, Ki HC, Lee BH, Kim IS, Ham MH. Low-Power Complementary Logic Circuit Using Polymer-Electrolyte-Gated Graphene Switching Devices. ACS APPLIED MATERIALS & INTERFACES 2019; 11:47247-47252. [PMID: 31746181 DOI: 10.1021/acsami.9b16417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The modulation of the electrical properties of graphene and its device configurations for low-power consumption are important in developing graphene-based logic electronics. Here, we demonstrate the change in the charge transport in graphene from ambipolar to unipolar using surface charge transfer doping of the polymer electrolyte. Unipolar graphene field-effect transistors (GFETs) were obtained by the surface treatment of poly(acrylic acid) (PAA) for p-type and poly(ethyleneimine) (PEI) for n-type as polymer-electrolyte gates. In addition, lithium perchlorate (LiClO4) in a polymer matrix can be used for the low-gate voltage operation of GFETs (less than ±3 V) because of its high gating efficiency. Using polymer-electrolyte-gated GFETs, complementary graphene inverters were fabricated with a voltage swing of 57% and maximum voltage gain (Vgain) of 1.1 at a low supply voltage (VDD = 1 V). This is expected to facilitate the development of graphene-based logic devices with low-cost, low-power, and flexible electronics.
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Affiliation(s)
- Myungwoo Son
- Photonic Energy Research Center , Korea Photonics Technology Institute (KOPTI) , Cheomdanbencheo-ro 108 beon-gil 9 , Buk-gu, Gwangju 61007 , Republic of Korea
| | | | | | | | - Hyun Chul Ki
- Photonic Energy Research Center , Korea Photonics Technology Institute (KOPTI) , Cheomdanbencheo-ro 108 beon-gil 9 , Buk-gu, Gwangju 61007 , Republic of Korea
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14
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Munther M, Shaygan M, Centeno A, Neumaier D, Zurutuza A, Momeni K, Davami K. Probing the mechanical properties of vertically-stacked ultrathin graphene/Al 2O 3 heterostructures. NANOTECHNOLOGY 2019; 30:185703. [PMID: 30630140 DOI: 10.1088/1361-6528/aafd53] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The superior intrinsic mechanical properties of graphene have been widely studied and utilized to enhance the mechanical properties of various composite materials. However, it is still unclear how heterostructures incorporating graphene behave, and to what extent graphene influences their mechanical response. In this work, a series of graphene/Al2O3 composite films were fabricated via atomic layer deposition of Al2O3 on graphene, and their mechanical behavior was studied using an experimental-computational approach. The inclusion of monolayer chemical vapor deposited graphene between ultrathin Al2O3 films (1.5-4.5 nm thickness) was found to enhance the overall stiffness by as much as 70% compared to a pure Al2O3 film of similar thickness (∼150 GPa to ∼250 GPa). Here, for the first time, the combination of graphene and Al2O3 in vertically-stacked heterostructures results in advanced hybrid films of unprecedented mechanical stiffness that also possess qualities desirable for graphene-based transistors and flexible electronics.
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Affiliation(s)
- Michael Munther
- Department of Mechanical Engineering, Lamar University, Beaumont, TX 77705, United States of America
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15
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Yavuz S, Loran EM, Sarkar N, Fenning DP, Bandaru PR. Enhanced Environmental Stability Coupled with a 12.5% Power Conversion Efficiency in an Aluminum Oxide-Encapsulated n-Graphene/p-Silicon Solar Cell. ACS APPLIED MATERIALS & INTERFACES 2018; 10:37181-37187. [PMID: 30280565 DOI: 10.1021/acsami.8b16322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A significant improvement in the power conversion efficiency (PCE) and the environmental stability of n-Graphene/p-Si solar cells is indicated through effective n-doping of graphene, using low work function oxide capping layers. AlO x, deposited through atomic layer deposition, is particularly effective for such doping and in addition serves as an antireflection coating and a cell encapsulating layer. It is shown that the related charge transfer doping and interfacial engineering was crucial to achieve a record PCE of 12.5%. The work indicates a path forward, through work function engineering, for further efficiency gains in Gr-based solar cells.
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16
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Uwanno T, Taniguchi T, Watanabe K, Nagashio K. Electrically Inert h-BN/Bilayer Graphene Interface in All-Two-Dimensional Heterostructure Field Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:28780-28788. [PMID: 30080037 DOI: 10.1021/acsami.8b08959] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bilayer graphene field effect transistors (BLG-FETs), unlike conventional semiconductors, are greatly sensitive to potential fluctuations because of the charged impurities in high- k gate stacks because the potential difference between two layers induced by the external perpendicular electrical filed is the physical origin behind the band gap opening. The assembly of BLG with layered h-BN insulators into a van der Waals heterostructure has been widely recognized to achieve the superior electrical transport properties. However, the carrier response properties at the h-BN/BLG heterointerface, which control the device performance, have not yet been revealed because of the inevitably large parasitic capacitance. In this study, the significant reduction of potential fluctuations to ∼1 meV is achieved in an all-two-dimensional heterostructure BLG-FET on a quartz substrate, which results in the suppression of the off-current to the measurement limit at a small band gap of ∼90 meV at 20 K. By capacitance measurement, we demonstrate that the electron trap/detrap response at such heterointerface is suppressed to undetectable level in the measurement frequency range. The electrically inert van der Waals heterointerface paves the way for the realization of future BLG electronics applications.
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Affiliation(s)
- Teerayut Uwanno
- Department of Materials Engineering , The University of Tokyo , Tokyo 113-8656 , Japan
- College of Nanotechnology , King Mongkut's Institute of Technology Ladkrabang , Bangkok 10520 , Thailand
| | | | - Kenji Watanabe
- National Institute of Materials Science , Ibaraki 305-0044 , Japan
| | - Kosuke Nagashio
- Department of Materials Engineering , The University of Tokyo , Tokyo 113-8656 , Japan
- PRESTO, Japan Science and Technology Agency (JST) , Tokyo 113-8656 , Japan
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17
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Shaikh JS, Shaikh NS, Mali SS, Patil JV, Pawar KK, Kanjanaboos P, Hong CK, Kim JH, Patil PS. Nanoarchitectures in dye-sensitized solar cells: metal oxides, oxide perovskites and carbon-based materials. NANOSCALE 2018; 10:4987-5034. [PMID: 29488524 DOI: 10.1039/c7nr08350e] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dye-sensitized solar cells (DSSCs) have aroused great interest and been regarded as a potential renewable energy resource among the third-generation solar cell technologies to fulfill the 21st century global energy demand. DSSCs have notable advantages such as low cost, easy fabrication process and being eco-friendly in nature. The progress of DSSCs over the last 20 years has been nearly constant due to some limitations, like poor long-term stability, narrow absorption spectrum, charge carrier transportation and collection losses and poor charge transfer mechanism for regeneration of dye molecules. The main challenge for the scientific community is to improve the performance of DSSCs by using different approaches, like finding new electrode materials with suitable nanoarchitectures, dyes in composition with promising semiconductors and metal quantum dot fluorescent dyes, and cost-effective hole transporting materials (HTMs). This review focuses on DSSC photo-physics, which includes charge separation, effective transportation, collection and recombination processes. Different nanostructured materials, including metal oxides, oxide perovskites and carbon-based composites, have been studied for photoanodes, and counter electrodes, which are crucial to achieve DSSC devices with higher efficiency and better stability.
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Affiliation(s)
- Jasmin S Shaikh
- Thin film materials laboratory, Department of Physics, Shivaji University, Kolhapur 416004, India.
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18
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Black A, Urbanos FJ, Osorio MR, Miranda R, Vázquez de Parga AL, Granados D. Encapsulating Chemically Doped Graphene via Atomic Layer Deposition. ACS APPLIED MATERIALS & INTERFACES 2018; 10:8190-8196. [PMID: 29461040 DOI: 10.1021/acsami.7b18709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling graphene's doping will be critically important for its incorporation into future electronic and optoelectronic devices. Noncovalent functionalization through adsorption of organic molecules on graphene's surface has proved to be a promising route for achieving p- or n-type doping. However, due to the poor adhesion of the molecules, these tend to desorb over time under standard environmental conditions or in the presence of certain solvents. The resulting reversal in the achieved chemical doping is a major obstacle to using organic molecules as noncovalent graphene dopants. In this work, we present a simple method for achieving long-term p- and n-doping of graphene devices through vapor phase evaporation of organic molecules, followed by encapsulation under an inert Al2O3 film. This film, grown via an optimized atomic layer deposition process, ensures long-term doping stability, as confirmed by electrical transport and Raman spectroscopy measurements. The doping is maintained even after storing the devices for six weeks in ambient conditions and immersing them in a dopant removing solvent, demonstrating that the film is as an effective barrier against environmental degradation of the doped devices.
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Affiliation(s)
- A Black
- IMDEA Nanociencia , 28049 Madrid , Spain
- Departamento de Física de la Materia Condensada , Universidad Autónoma de Madrid , 28049 Madrid , Spain
| | - F J Urbanos
- IMDEA Nanociencia , 28049 Madrid , Spain
- Departamento de Física de la Materia Condensada , Universidad Autónoma de Madrid , 28049 Madrid , Spain
| | - M R Osorio
- IMDEA Nanociencia , 28049 Madrid , Spain
| | - R Miranda
- IMDEA Nanociencia , 28049 Madrid , Spain
- Departamento de Física de la Materia Condensada , Universidad Autónoma de Madrid , 28049 Madrid , Spain
- Condensed Matter Physics Center (IFIMAC) , Universidad Autónoma de Madrid , 28049 Madrid , Spain
| | - A L Vázquez de Parga
- IMDEA Nanociencia , 28049 Madrid , Spain
- Departamento de Física de la Materia Condensada , Universidad Autónoma de Madrid , 28049 Madrid , Spain
- Condensed Matter Physics Center (IFIMAC) , Universidad Autónoma de Madrid , 28049 Madrid , Spain
| | - D Granados
- IMDEA Nanociencia , 28049 Madrid , Spain
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19
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Cabrero-Vilatela A, Alexander-Webber JA, Sagade AA, Aria AI, Braeuninger-Weimer P, Martin MB, Weatherup RS, Hofmann S. Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer. NANOTECHNOLOGY 2017; 28:485201. [PMID: 29039352 DOI: 10.1088/1361-6528/aa940c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The transfer of chemical vapour deposited graphene from its parent growth catalyst has become a bottleneck for many of its emerging applications. The sacrificial polymer layers that are typically deposited onto graphene for mechanical support during transfer are challenging to remove completely and hence leave graphene and subsequent device interfaces contaminated. Here, we report on the use of atomic layer deposited (ALD) oxide films as protective interface and support layers during graphene transfer. The method avoids any direct contact of the graphene with polymers and through the use of thicker ALD layers (≥100 nm), polymers can be eliminated from the transfer-process altogether. The ALD film can be kept as a functional device layer, facilitating integrated device manufacturing. We demonstrate back-gated field effect devices based on single-layer graphene transferred with a protective Al2O3 film onto SiO2 that show significantly reduced charge trap and residual carrier densities. We critically discuss the advantages and challenges of processing graphene/ALD bilayer structures.
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Affiliation(s)
- A Cabrero-Vilatela
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
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20
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Shaygan M, Wang Z, Elsayed MS, Otto M, Iannaccone G, Ghareeb AH, Fiori G, Negra R, Neumaier D. High performance metal-insulator-graphene diodes for radio frequency power detection application. NANOSCALE 2017; 9:11944-11950. [PMID: 28792041 DOI: 10.1039/c7nr02793a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Vertical metal-insulator-graphene (MIG) diodes for radio frequency (RF) power detection are realized using a scalable approach based on graphene grown by chemical vapor deposition and TiO2 as barrier material. The temperature dependent current flow through the diode can be described by thermionic emission theory taking into account a bias induced barrier lowering at the graphene TiO2 interface. The diodes show excellent figures of merit for static operation, including high on-current density of up to 28 A cm-2, high asymmetry of up to 520, strong maximum nonlinearity of up to 15, and large maximum responsivity of up to 26 V-1, outperforming state-of-the-art metal-insulator-metal and MIG diodes. RF power detection based on MIG diodes is demonstrated, showing a responsivity of 2.8 V W-1 at 2.4 GHz and 1.1 V W-1 at 49.4 GHz.
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Affiliation(s)
- Mehrdad Shaygan
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany.
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21
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Ruhl G, Wittmann S, Koenig M, Neumaier D. The integration of graphene into microelectronic devices. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:1056-1064. [PMID: 28685106 PMCID: PMC5480353 DOI: 10.3762/bjnano.8.107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/25/2017] [Indexed: 05/14/2023]
Abstract
Since 2004 the field of graphene research has attracted increasing interest worldwide. Especially the integration of graphene into microelectronic devices has the potential for numerous applications. Therefore, we summarize the current knowledge on this aspect. Surveys show that considerable progress was made in the field of graphene synthesis. However, the central issue consists of the availability of techniques suitable for production for the deposition of graphene on dielectric substrates. Besides, the encapsulation of graphene for further processing while maintaining its properties poses a challenge. Regarding the graphene/metal contact intensive research was done and recently substantial advancements were made towards contact resistances applicable for electronic devices. Generally speaking the crucial issues for graphene integration are identified today and the corresponding research tasks can be clearly defined.
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Affiliation(s)
- Guenther Ruhl
- Infineon Technologies AG, Wernerwerkstrasse 2, 93049 Regensburg, Germany
| | - Sebastian Wittmann
- Infineon Technologies AG, Wernerwerkstrasse 2, 93049 Regensburg, Germany
- Nanochem CoE, OTH Regensburg, Seybothstrasse 2, 93053 Regensburg, Germany
| | - Matthias Koenig
- Infineon Technologies AG, Wernerwerkstrasse 2, 93049 Regensburg, Germany
- University of Siegen, Department of Electrical Engineering and Computer Science, Hölderlinstr. 3, 57076 Siegen, Germany
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22
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Temperature and pH sensors based on graphenic materials. Biosens Bioelectron 2017; 91:870-877. [DOI: 10.1016/j.bios.2017.01.062] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 11/23/2022]
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23
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Fisichella G, Schilirò E, Di Franco S, Fiorenza P, Lo Nigro R, Roccaforte F, Ravesi S, Giannazzo F. Interface Electrical Properties of Al 2O 3 Thin Films on Graphene Obtained by Atomic Layer Deposition with an in Situ Seedlike Layer. ACS APPLIED MATERIALS & INTERFACES 2017; 9:7761-7771. [PMID: 28135063 DOI: 10.1021/acsami.6b15190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
High-quality thin insulating films on graphene (Gr) are essential for field-effect transistors (FETs) and other electronics applications of this material. Atomic layer deposition (ALD) is the method of choice to deposit high-κ dielectrics with excellent thickness uniformity and conformal coverage. However, to start the growth on the sp2 Gr surface, a chemical prefunctionalization or the physical deposition of a seed layer are required, which can effect, to some extent, the electrical properties of Gr. In this paper, we report a detailed morphological, structural, and electrical investigation of Al2O3 thin films grown by a two-steps ALD process on a large area Gr membrane residing on an Al2O3-Si substrate. This process consists of the H2O-activated deposition of a Al2O3 seed layer a few nanometers in thickness, performed in situ at 100 °C, followed by ALD thermal growth of Al2O3 at 250 °C. The optimization of the low-temperature seed layer allowed us to obtain a uniform, conformal, and pinhole-free Al2O3 film on Gr by the second ALD step. Nanoscale-resolution mapping of the current through the dielectric by conductive atomic force microscopy (CAFM) demonstrated an excellent laterally uniformity of the film. Raman spectroscopy measurements indicated that the ALD process does not introduce defects in Gr, whereas it produces a partial compensation of Gr unintentional p-type doping, as confirmed by the increase of Gr sheet resistance (from ∼300 Ω/sq in pristine Gr to ∼1100 Ω/sq after Al2O3 deposition). Analysis of the transfer characteristics of Gr field-effect transistors (GFETs) allowed us to evaluate the relative dielectric permittivity (ε = 7.45) and the breakdown electric field (EBD = 7.4 MV/cm) of the Al2O3 film as well as the transconductance and the holes field-effect mobility (∼1200 cm2 V-1 s-1). A special focus has been given to the electrical characterization of the Al2O3-Gr interface by the analysis of high frequency capacitance-voltage measurements, which allowed us to elucidate the charge trapping and detrapping phenomena due to near-interface and interface oxide traps.
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Affiliation(s)
- Gabriele Fisichella
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Emanuela Schilirò
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Salvatore Di Franco
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Patrick Fiorenza
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Raffaella Lo Nigro
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Fabrizio Roccaforte
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
| | - Sebastiano Ravesi
- STMicroelectronics , Stradale Primosole 50, Zona Industriale, 95121 Catania, Italy
| | - Filippo Giannazzo
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi , Strada VIII, n. 5, Zona Industriale, 95121 Catania, Italy
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24
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Habibpour O, He ZS, Strupinski W, Rorsman N, Zirath H. Wafer scale millimeter-wave integrated circuits based on epitaxial graphene in high data rate communication. Sci Rep 2017; 7:41828. [PMID: 28145513 PMCID: PMC5286424 DOI: 10.1038/srep41828] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/28/2016] [Indexed: 11/09/2022] Open
Abstract
In recent years, the demand for high data rate wireless communications has increased dramatically, which requires larger bandwidth to sustain multi-user accessibility and quality of services. This can be achieved at millimeter wave frequencies. Graphene is a promising material for the development of millimeter-wave electronics because of its outstanding electron transport properties. Up to now, due to the lack of high quality material and process technology, the operating frequency of demonstrated circuits has been far below the potential of graphene. Here, we present monolithic integrated circuits based on epitaxial graphene operating at unprecedented high frequencies (80–100 GHz). The demonstrated circuits are capable of encoding/decoding of multi-gigabit-per-second information into/from the amplitude or phase of the carrier signal. The developed fabrication process is scalable to large wafer sizes.
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Affiliation(s)
- Omid Habibpour
- Chalmers University of Technology, Gothenburg 41296, Sweden
| | | | - Wlodek Strupinski
- Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland
| | - Niklas Rorsman
- Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Herbert Zirath
- Chalmers University of Technology, Gothenburg 41296, Sweden
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25
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Aria AI, Nakanishi K, Xiao L, Braeuninger-Weimer P, Sagade AA, Alexander-Webber JA, Hofmann S. Parameter Space of Atomic Layer Deposition of Ultrathin Oxides on Graphene. ACS APPLIED MATERIALS & INTERFACES 2016; 8:30564-30575. [PMID: 27723305 PMCID: PMC5257172 DOI: 10.1021/acsami.6b09596] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/10/2016] [Indexed: 05/26/2023]
Abstract
Atomic layer deposition (ALD) of ultrathin aluminum oxide (AlOx) films was systematically studied on supported chemical vapor deposition (CVD) graphene. We show that by extending the precursor residence time, using either a multiple-pulse sequence or a soaking period, ultrathin continuous AlOx films can be achieved directly on graphene using standard H2O and trimethylaluminum (TMA) precursors even at a high deposition temperature of 200 °C, without the use of surfactants or other additional graphene surface modifications. To obtain conformal nucleation, a precursor residence time of >2s is needed, which is not prohibitively long but sufficient to account for the slow adsorption kinetics of the graphene surface. In contrast, a shorter residence time results in heterogeneous nucleation that is preferential to defect/selective sites on the graphene. These findings demonstrate that careful control of the ALD parameter space is imperative in governing the nucleation behavior of AlOx on CVD graphene. We consider our results to have model system character for rational two-dimensional (2D)/non-2D material process integration, relevant also to the interfacing and device integration of the many other emerging 2D materials.
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26
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Deep-submicron Graphene Field-Effect Transistors with State-of-Art f max. Sci Rep 2016; 6:35717. [PMID: 27775009 PMCID: PMC5075922 DOI: 10.1038/srep35717] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 10/03/2016] [Indexed: 11/25/2022] Open
Abstract
In order to conquer the short-channel effects that limit conventional ultra-scale semiconductor devices, two-dimensional materials, as an option of ultimate thin channels, receive wide attention. Graphene, in particular, bears great expectations because of its supreme carrier mobility and saturation velocity. However, its main disadvantage, the lack of bandgap, has not been satisfactorily solved. As a result, maximum oscillation frequency (fmax) which indicates transistors’ power amplification ability has been disappointing. Here, we present submicron field-effect transistors with specially designed low-resistance gate and excellent source/drain contact, and therefore significantly improved fmax. The fabrication was assisted by the advanced 8-inch CMOS back-end-of-line technology. A 200-nm-gate-length GFET achieves fT/fmax = 35.4/50 GHz. All GFET samples with gate lengths ranging from 200 nm to 400 nm possess fmax 31–41% higher than fT, closely resembling Si n-channel MOSFETs at comparable technology nodes. These results re-strengthen the promise of graphene field-effect transistors in next generation semiconductor electronics.
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27
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Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior. Sci Rep 2016; 6:33118. [PMID: 27609184 PMCID: PMC5016828 DOI: 10.1038/srep33118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/19/2016] [Indexed: 11/20/2022] Open
Abstract
We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene.
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28
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Williams JOD, Alexander-Webber JA, Lapington JS, Roy M, Hutchinson IB, Sagade AA, Martin MB, Braeuninger-Weimer P, Cabrero-Vilatela A, Wang R, De Luca A, Udrea F, Hofmann S. Towards a Graphene-Based Low Intensity Photon Counting Photodetector. SENSORS (BASEL, SWITZERLAND) 2016; 16:E1351. [PMID: 27563903 PMCID: PMC5038629 DOI: 10.3390/s16091351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/15/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Graphene is a highly promising material in the development of new photodetector technologies, in particular due its tunable optoelectronic properties, high mobilities and fast relaxation times coupled to its atomic thinness and other unique electrical, thermal and mechanical properties. Optoelectronic applications and graphene-based photodetector technology are still in their infancy, but with a range of device integration and manufacturing approaches emerging this field is progressing quickly. In this review we explore the potential of graphene in the context of existing single photon counting technologies by comparing their performance to simulations of graphene-based single photon counting and low photon intensity photodetection technologies operating in the visible, terahertz and X-ray energy regimes. We highlight the theoretical predictions and current graphene manufacturing processes for these detectors. We show initial experimental implementations and discuss the key challenges and next steps in the development of these technologies.
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Affiliation(s)
- Jamie O D Williams
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Jack A Alexander-Webber
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Jon S Lapington
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Mervyn Roy
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Ian B Hutchinson
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Abhay A Sagade
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Marie-Blandine Martin
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | | | - Andrea Cabrero-Vilatela
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Ruizhi Wang
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Andrea De Luca
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Florin Udrea
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
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Shautsova V, Gilbertson AM, Black NCG, Maier SA, Cohen LF. Hexagonal Boron Nitride assisted transfer and encapsulation of large area CVD graphene. Sci Rep 2016; 6:30210. [PMID: 27443219 PMCID: PMC4957148 DOI: 10.1038/srep30210] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/29/2016] [Indexed: 11/24/2022] Open
Abstract
We report a CVD hexagonal boron nitride (hBN-) assisted transfer method that enables a polymer-impurity free transfer process and subsequent top encapsulation of large-area CVD-grown graphene. We demonstrate that the CVD hBN layer that is utilized in this transfer technique acts as a buffer layer between the graphene film and supporting polymer layer. We show that the resulting graphene layers possess lower doping concentration, and improved carrier mobilities compared to graphene films produced by conventional transfer methods onto untreated SiO2/Si, SAM-modified and hBN covered SiO2/Si substrates. Moreover, we show that the top hBN layer used in the transfer process acts as an effective top encapsulation resulting in improved stability to ambient exposure. The transfer method is applicable to other CVD-grown 2D materials on copper foils, thereby facilitating the preparation of van der Waals heterostructures with controlled doping.
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Affiliation(s)
- Viktoryia Shautsova
- Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ, UK
| | - Adam M Gilbertson
- Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ, UK
| | - Nicola C G Black
- Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ, UK.,National Physical Laboratory, Hampton Rd, Teddington, Middlesex TW11 0LW, UK
| | - Stefan A Maier
- Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ, UK
| | - Lesley F Cohen
- Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ, UK
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30
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Montanaro A, Mzali S, Mazellier JP, Bezencenet O, Larat C, Molin S, Morvan L, Legagneux P, Dolfi D, Dlubak B, Seneor P, Martin MB, Hofmann S, Robertson J, Centeno A, Zurutuza A. Thirty Gigahertz Optoelectronic Mixing in Chemical Vapor Deposited Graphene. NANO LETTERS 2016; 16:2988-93. [PMID: 27043922 DOI: 10.1021/acs.nanolett.5b05141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The remarkable properties of graphene, such as broadband optical absorption, high carrier mobility, and short photogenerated carrier lifetime, are particularly attractive for high-frequency optoelectronic devices operating at 1.55 μm telecom wavelength. Moreover, the possibility to transfer graphene on a silicon substrate using a complementary metal-oxide-semiconductor-compatible process opens the ability to integrate electronics and optics on a single cost-effective chip. Here, we report an optoelectronic mixer based on chemical vapor-deposited graphene transferred on an oxidized silicon substrate. Our device consists in a coplanar waveguide that integrates a graphene channel, passivated with an atomic layer-deposited Al2O3 film. With this new structure, 30 GHz optoelectronic mixing in commercially available graphene is demonstrated for the first time. In particular, using a 30 GHz intensity-modulated optical signal and a 29.9 GHz electrical signal, we show frequency downconversion to 100 MHz. These results open promising perspectives in the domain of optoelectronics for radar and radio-communication systems.
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Affiliation(s)
- Alberto Montanaro
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Sana Mzali
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Jean-Paul Mazellier
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Odile Bezencenet
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Christian Larat
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Stephanie Molin
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Loïc Morvan
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Pierre Legagneux
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Daniel Dolfi
- Thales Research and Technology , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Bruno Dlubak
- Unité Mixte de Physique CNRS/Thales , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Pierre Seneor
- Unité Mixte de Physique CNRS/Thales , 1, Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Marie-Blandine Martin
- Department of Engineering, University of Cambridge , Cambridge CB21PZ, United Kingdom
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge , Cambridge CB21PZ, United Kingdom
| | - John Robertson
- Department of Engineering, University of Cambridge , Cambridge CB21PZ, United Kingdom
| | - Alba Centeno
- Graphenea S.A. , Tolosa Hiribidea, 76 E-20018 Donostia, Spain
| | - Amaia Zurutuza
- Graphenea S.A. , Tolosa Hiribidea, 76 E-20018 Donostia, Spain
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31
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Wang Z, Shaygan M, Otto M, Schall D, Neumaier D. Flexible Hall sensors based on graphene. NANOSCALE 2016; 8:7683-7687. [PMID: 26997245 DOI: 10.1039/c5nr08729e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 μm thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT(-1) and 79 V AT(-1) were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm.
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Affiliation(s)
- Zhenxing Wang
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
| | - Mehrdad Shaygan
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
| | - Martin Otto
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
| | - Daniel Schall
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
| | - Daniel Neumaier
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
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32
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Lyu H, Lu Q, Huang Y, Ma T, Zhang J, Wu X, Yu Z, Ren W, Cheng HM, Wu H, Qian H. Graphene Distributed Amplifiers: Generating Desirable Gain for Graphene Field-Effect Transistors. Sci Rep 2015; 5:17649. [PMID: 26634442 PMCID: PMC4669444 DOI: 10.1038/srep17649] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/03/2015] [Indexed: 11/11/2022] Open
Abstract
Ever since its discovery, graphene bears great expectations in high frequency electronics due to its irreplaceably high carrier mobility. However, it has long been blamed for the weakness in generating gains, which seriously limits its pace of development. Distributed amplification, on the other hand, has successfully been used in conventional semiconductors to increase the amplifiers’ gain-bandwidth product. In this paper, distributed amplification is first applied to graphene. Transmission lines phase-synchronize paralleled graphene field-effect transistors (GFETs), combining the gain of each stage in an additive manner. Simulations were based on fabricated GFETs whose fT ranged from 8.5 GHz to 10.5 GHz and fmax from 12 GHz to 14 GHz. A simulated four-stage graphene distributed amplifier achieved up to 4 dB gain and 3.5 GHz bandwidth, which could be realized with future IC processes. A PCB level graphene distributed amplifier was fabricated as a proof of circuit concept.
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Affiliation(s)
- Hongming Lyu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China.,Department of Electrical &Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA9
| | - Qi Lu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Yilin Huang
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Teng Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Jinyu Zhang
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Xiaoming Wu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Zhiping Yu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Hui-Ming Cheng
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Huaqiang Wu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China.,Tsinghua National Laboratory for Information Science and Technology (TNList), Beijing, 100084, China
| | - He Qian
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China.,Tsinghua National Laboratory for Information Science and Technology (TNList), Beijing, 100084, China
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33
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Lyu H, Wu H, Liu J, Lu Q, Zhang J, Wu X, Li J, Ma T, Niu J, Ren W, Cheng H, Yu Z, Qian H. Double-Balanced Graphene Integrated Mixer with Outstanding Linearity. NANO LETTERS 2015; 15:6677-6682. [PMID: 26378374 DOI: 10.1021/acs.nanolett.5b02503] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A monolithic double-balanced graphene mixer integrated circuit (IC) has been successfully designed and fabricated. The IC adopted the cross-coupled resistive mixer topology, integrating four 500 nm-gate-length graphene field-effect transistors (GFETs), four on-chip inductors, and four on-chip capacitors. Passive-first-active-last fabrication flow was developed on 200 mm CMOS wafers. CMOS back-end-of-line processes were utilized to realize most fabrication steps followed by GFET-customized processes. Test results show excellent output spectrum purity with suppressed radio frequency (RF) and local oscillation (LO) signals feedthroughs, and third-order input intercept (IIP3) reaches as high as 21 dBm. The results are compared with a fabricated single-GEFT mixer, which generates IIP3 of 16.5 dBm. Stand-alone 500 nm-gate-length GFETs feature cutoff frequency 22 GHz and maximum oscillation frequency 20.7 GHz RF performance. The double-balanced mixer IC operated with off-chip baluns realizing a print-circuit-board level electronic system. It demonstrates graphene's potential to compete with other semiconductor technologies in RF front-end applications.
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Affiliation(s)
- Hongming Lyu
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
| | - Huaqiang Wu
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
- Tsinghua National Laboratory for Information Science and Technology (TNList) , Beijing, China , 100084
| | - Jinbiao Liu
- Institute of Microelectronics, Chinese Academy of Sciences , Haidian District, Beijing, China 100029
| | - Qi Lu
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
| | - Jinyu Zhang
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
| | - Xiaoming Wu
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
| | - Junfeng Li
- Institute of Microelectronics, Chinese Academy of Sciences , Haidian District, Beijing, China 100029
| | - Teng Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang, China , 110016
| | - Jiebin Niu
- Institute of Microelectronics, Chinese Academy of Sciences , Haidian District, Beijing, China 100029
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang, China , 110016
| | - Huiming Cheng
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang, China , 110016
| | - Zhiping Yu
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
| | - He Qian
- Institute of Microelectronics, Tsinghua University , Beijing, China 100084
- Tsinghua National Laboratory for Information Science and Technology (TNList) , Beijing, China , 100084
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34
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