Overcoming Materials Challenges to Achieve Carbon Nanotube Array Transistors with Current Density Exceeding Si and GaAs PDF Download
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Author: Gerald Joseph Brady
Publisher:
ISBN:
Category :
Languages : en
Pages : 172
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Book Description
Single walled carbon nanotubes (SWCNTs) have extraordinarily high current carrying capacity, tunable band gap, and can be solution processed at low temperatures making them an attractive candidate to complement or replace bulk semiconducting materials in next generation electronics. Critical materials roadblocks that have limited the performance of SWCNTs in electronics, however, are 1) the isolation of electronically homogeneous SWCNTs, 2) the hierarchical organization of SWCNT building blocks into organized assemblies, 3) reducing defects and impurities, and 4) making intimate electrical contacts to SWCNT films. Here I will present my progress in harnessing arrays of purely semiconducting SWCNTs as the active channel material for high-performance field-effect transistors (FETs) at short channel lengths (30 - 300 nm) where a majority of the SWCNTs directly span the source-drain channel. Conjugated polymers are used to selectively wrap and separate highly enriched semiconducting SWCNTs from electronically heterogeneous arc-discharge SWCNT powders. The semiconducting SWCNTs dispersed in organic-solvent are then aligned into arrays via a technique we pioneered that exploits solvent spreading and self-assembly of SWCNTs at the water-chloroform interface. Solvent rinsing and thermal annealing treatments are performed on the SWCNT array thin films to remove processing induced contaminants and residual polymer as confirmed by XPS, UV-Vis, and FTIR spectroscopy. The combination of high semiconducting purity, pristine quality achieved through surface treatment, and the ideal microstructure of the SWCNT array enables FETs with 7x higher current density than previous state-of-the-art SWCNT FETs. The saturated on-state current density exceeds Si and GaAs FETs of similar dimensions and off-state current density, which demonstrates the competitive advantage of these SWCNT arrays for logic, wireless communications, biological sensors and other semiconductor electronics technologies.
Author: Gerald Joseph Brady
Publisher:
ISBN:
Category :
Languages : en
Pages : 172
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Book Description
Single walled carbon nanotubes (SWCNTs) have extraordinarily high current carrying capacity, tunable band gap, and can be solution processed at low temperatures making them an attractive candidate to complement or replace bulk semiconducting materials in next generation electronics. Critical materials roadblocks that have limited the performance of SWCNTs in electronics, however, are 1) the isolation of electronically homogeneous SWCNTs, 2) the hierarchical organization of SWCNT building blocks into organized assemblies, 3) reducing defects and impurities, and 4) making intimate electrical contacts to SWCNT films. Here I will present my progress in harnessing arrays of purely semiconducting SWCNTs as the active channel material for high-performance field-effect transistors (FETs) at short channel lengths (30 - 300 nm) where a majority of the SWCNTs directly span the source-drain channel. Conjugated polymers are used to selectively wrap and separate highly enriched semiconducting SWCNTs from electronically heterogeneous arc-discharge SWCNT powders. The semiconducting SWCNTs dispersed in organic-solvent are then aligned into arrays via a technique we pioneered that exploits solvent spreading and self-assembly of SWCNTs at the water-chloroform interface. Solvent rinsing and thermal annealing treatments are performed on the SWCNT array thin films to remove processing induced contaminants and residual polymer as confirmed by XPS, UV-Vis, and FTIR spectroscopy. The combination of high semiconducting purity, pristine quality achieved through surface treatment, and the ideal microstructure of the SWCNT array enables FETs with 7x higher current density than previous state-of-the-art SWCNT FETs. The saturated on-state current density exceeds Si and GaAs FETs of similar dimensions and off-state current density, which demonstrates the competitive advantage of these SWCNT arrays for logic, wireless communications, biological sensors and other semiconductor electronics technologies.
Author: Sean Michael Foradori
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Semiconducting, single walled carbon nanotubes (CNTs) are exceptional electronic materials with high current carrying capacity, a tunable band gap, and nanoscale dimensions. Single CNTs in research devices have demonstrated these excellent material properties. Extrapolation of these single CNT results to devices with many CNTs in tightly packed and highly aligned arrays indicates that CNTs can exceed the performance of existing silicon based devices in many applications by operating at lower voltages and using less energy. The performance of array based devices has not yet met these high expectations, however, due in part to practical challenges in fabricating arrays and integrating those arrays into devices. Aligned arrays can be deposited using many different processes to generate a wide range of CNT packing densities and array morphologies. The morphology and packing density both can affect device performance. Polymer wrapped CNTs with high semiconductor purity are often used in these arrays, but the polymer wrapper must be removed from the CNT array to achieve the best device performance. Chapter 2 examines the impact of CNT bundles on the performance of field effect transistors (FETs) with relatively weak gates. These bundles, colinear aggregates containing multiple CNTs, are formed during some array fabrication processes and can behave differently from individual CNTs. When using relatively weak gates, bundles have a current density similar to individual CNTs, but they have different threshold voltages than individual CNTs, meaning their conductivity turns on and off at different gate voltages. Arrays with a mixture of individual and bundled CNTs make devices with poor subthreshold swing because the gate cannot turn the whole array off at any particular voltage; the array turns off gradually as the gate voltage changes. Chapter 3 examines bundles in FETs with strong ion gel gates. A strong gate can turn on multiple CNTs in a bundle, increasing their current density relative to individual CNTs. An FET with a strong gate and a CNT array containing many bundles will have a higher transconductance than a device with an array containing only individual CNTs. This can be useful in radio frequency transistors because their high frequency performance improves as transconductance increases, but is degraded by parasitic capacitance effects if the channel width is increased. By using an array of bundled CNTs instead of an array of individual CNTs, the transconductance can be increased without increasing the channel width. Chapter 4 describes a strategy to fabricate monolayer arrays with high packing density and very little bundling. Passing a substrate through a macroscopic liquid-liquid interface can deposit aligned arrays of CNTs at the liquid-liquid-substrate contact line. The new strategy uses lithographically defined, microscopic water droplets on substrates to form a contact line that is more stable and improves the array deposition. The advantage of patterned microscopic droplets is that the contact line is pinned by the hydrophilic/hydrophobic border of the chemical pattern, and is decoupled from the motions of the substrate and macroscopic liquid-liquid interface. This relatively stable contact line moves as each CNT is deposited, allowing subsequent CNTs to deposit adjacent to the previously deposited ones, improving the alignment and increasing the packing density to 250 CNTs ℗æm-1 with very little bundling. Devices made using these arrays have exceptionally high current density and transconductance of 1.9 mA ℗æm-1 and 1.2 mS ℗æm-1 at a channel length of 60 nm using just a 0.6 V drain voltage. This is a >2x performance improvement over arrays formed with similar conditions but deposited at the contact line of the macroscopic interface. Finally, Chapter 5 investigates a yttrium (Y) based post-deposition process used to mitigate the effects of wrapping polymer in CNT FETs. Though this process has been used for several years, very little information has been reported about how it works. We use physical and spectroscopic measurements to examine the mechanism, selectivity, extent of etching, and range of conditions available for removing the wrapping polymer PFO-BPy from CNTs. The Y-treatment process consists of depositing 3 nm of metallic Y on the sample, annealing in air at a fixed temperature and time, then etching the sample in dilute HCl for 5 seconds, and rinsing in DI water. Annealing at 90°C or cooler for 30 minutes will oxidize ~0.5 nm of a PFO-BPy film, forming highly oxidized carbonate, carboxylate and/or carbonyl groups, allowing it to dissolve in dilute aqueous acid. Repeated Y-treatment cycles will etch more material, and thicker layers of up to 2.5 nm can be etched by annealing at 250°C for 120 minutes. Reactions with sp2 based CNTs and graphene only occur at elevated temperatures, allowing selective removal of wrapping polymer from CNTs at lower temperatures. Furthermore, the yttrium process can remove all parts of the PFO-BPy polymer molecule, in contrast to high-temperature vacuum annealing which only removes alkyl side groups and leaves much of the polymer chain intact.
Author: Changjian Zhou
Publisher: CRC Press
ISBN: 1000064719
Category : Technology & Engineering
Languages : en
Pages : 279
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Book Description
This book presents a comprehensive review of research on applications of carbon nanotubes (CNTs) and graphene to electronic devices. As nanocarbons in general, and CNTs and graphene in particular, are becoming increasingly recognized as the most promising materials for future generations of electronic devices, including transistors, sensors, and interconnects, a knowledge gap still exists between the basic science of nanocarbons and their feasibility for cost-effective product manufacturing. The book highlights some of the issues surrounding this missing link by providing a detailed review of the nanostructure and electronic properties, materials, and device fabrication and of the structure–property–application relationships.
Author: Zhifeng Ren
Publisher: Springer Science & Business Media
ISBN: 3642304907
Category : Science
Languages : en
Pages : 310
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Book Description
This book gives a survey of the physics and fabrication of carbon nanotubes and their applications in optics, electronics, chemistry and biotechnology. It focuses on the structural characterization of various carbon nanotubes, fabrication of vertically or parallel aligned carbon nanotubes on substrates or in composites, physical properties for their alignment, and applications of aligned carbon nanotubes in field emission, optical antennas, light transmission, solar cells, chemical devices, bio-devices, and many others. Major fabrication methods are illustrated in detail, particularly the most widely used PECVD growth technique on which various device integration schemes are based, followed by applications such as electrical interconnects, nanodiodes, optical antennas, and nanocoax solar cells, whereas current limitations and challenges are also be discussed to lay the foundation for future developments.
Author: Ashok Srivastava
Publisher: CRC Press
ISBN: 9814613118
Category : Science
Languages : en
Pages : 153
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Book Description
Discovery of one-dimensional material carbon nanotubes in 1991 by the Japanese physicist Dr. Sumio Iijima has resulted in voluminous research in the field of carbon nanotubes for numerous applications, including possible replacement of silicon used in the fabrication of CMOS chips. One interesting feature of carbon nanotubes is that these can be me
Author: Kazuhiko Matsumoto
Publisher: Springer
ISBN: 443155372X
Category : Technology & Engineering
Languages : en
Pages : 295
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Book Description
This book focuses on carbon nanotubes and graphene as representatives of nano-carbon materials, and describes the growth of new technology and applications of new devices. As new devices and as new materials, nano-carbon materials are expected to be world pioneers that could not have been realized with conventional semiconductor materials, and as those that extend the limits of conventional semiconductor performance. This book introduces the latest achievements of nano-carbon devices, processes, and technology growth. It is anticipated that these studies will also be pioneers in the development of future research of nano-carbon devices and materials. This book consists of 18 chapters. Chapters 1 to 8 describe new device applications and new growth methods of graphene, and Chapters 9 to 18, those of carbon nanotubes. It is expected that by increasing the advantages and overcoming the weak points of nanocarbon materials, a new world that cannot be achieved with conventional materials will be greatly expanded. We strongly hope this book contributes to its development.
Author: Ali Javey
Publisher: Springer Science & Business Media
ISBN: 0387692851
Category : Technology & Engineering
Languages : en
Pages : 275
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Book Description
This book provides a complete overview of the field of carbon nanotube electronics. It covers materials and physical properties, synthesis and fabrication processes, devices and circuits, modeling, and finally novel applications of nanotube-based electronics. The book introduces fundamental device physics and circuit concepts of 1-D electronics. At the same time it provides specific examples of the state-of-the-art nanotube devices.
Author: Prasanta Ghosh
Publisher: BoD – Books on Demand
ISBN: 1838811842
Category : Technology & Engineering
Languages : en
Pages : 184
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Book Description
Carbon Nanotubes - Redefining the World of Electronics is a compendium of current, state-of-the-art information about carbon nanotubes (CNTs) and their potential applications in electronics. Chapters cover such topics as the incorporation of CNTs into electronic devices, CNT-based rubber composites for electronic components, the role of CNTs in different energy storage and conversion systems, and ternary implementations of carbon nanotube field-effect transistor (CNTFET) circuits.
Author: Fouad Sabry
Publisher: One Billion Knowledgeable
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 500
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Book Description
What Is Carbon Nanotube Field Effect Transistor A carbon nanotube field-effect transistor, also known as a CNTFET, is a kind of field-effect transistor that makes use of a single carbon nanotube or an array of carbon nanotubes as the channel material in place of bulk silicon, as is done in the conventional MOSFET construction. Since they were first exhibited in 1998, there have been significant advancements in CNTFET technology. How You Will Benefit (I) Insights, and validations about the following topics: Chapter 1: Carbon nanotube field-effect transistor Chapter 2: Carbon nanotube Chapter 3: JFET Chapter 4: Schottky barrier Chapter 5: Electron mobility Chapter 6: Nanoelectromechanical systems Chapter 7: Threshold voltage Chapter 8: Organic field-effect transistor Chapter 9: Ballistic conduction Chapter 10: Hybrid solar cell Chapter 11: Potential applications of carbon nanotubes Chapter 12: Carbon nanotubes in photovoltaics Chapter 13: Optical properties of carbon nanotubes Chapter 14: Carbon nanotube nanomotor Chapter 15: NanoIntegris Chapter 16: Ballistic conduction in single-walled carbon nanotubes Chapter 17: Tunnel field-effect transistor Chapter 18: Field-effect transistor Chapter 19: Carbon nanotubes in interconnects Chapter 20: Synthesis of carbon nanotubes Chapter 21: Vertically aligned carbon nanotube arrays (II) Answering the public top questions about carbon nanotube field effect transistor. (III) Real world examples for the usage of carbon nanotube field effect transistor in many fields. (IV) 17 appendices to explain, briefly, 266 emerging technologies in each industry to have 360-degree full understanding of carbon nanotube field effect transistor' technologies. Who This Book Is For Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of carbon nanotube field effect transistor.
Author: Aida Todri-Sanial
Publisher: Springer
ISBN: 3319297465
Category : Technology & Engineering
Languages : en
Pages : 340
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Book Description
This book provides a single-source reference on the use of carbon nanotubes (CNTs) as interconnect material for horizontal, on-chip and 3D interconnects. The authors demonstrate the uses of bundles of CNTs, as innovative conducting material to fabricate interconnect through-silicon vias (TSVs), in order to improve the performance, reliability and integration of 3D integrated circuits (ICs). This book will be first to provide a coherent overview of exploiting carbon nanotubes for 3D interconnects covering aspects from processing, modeling, simulation, characterization and applications. Coverage also includes a thorough presentation of the application of CNTs as horizontal on-chip interconnects which can potentially revolutionize the nanoelectronics industry. This book is a must-read for anyone interested in the state-of-the-art on exploiting carbon nanotubes for interconnects for both 2D and 3D integrated circuits.
