Carbon Nanotubes: The Building Blocks of Nanotechnology Development (original) (raw)
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Carbon nanotubes: synthesis, properties and engineering applications
Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp 2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.
CARBON NANOTUBES SCIENCE AND APPLICATIONS
The extraordinary mechanical properties and unique electrical properties of carbon nanotubes (CNTs) have stimulated extensive research activities across the world since their discovery by Sumio Iijima of the NEC Corporation in the early 1990s. Although early research focused on growth and characterization, these interesting properties have led to an increase in the number of investigations focused on application development in the past 5 years. The breadth of applications for carbon nanotubes is indeed wide ranging: nanoelectronics, quantum wire interconnects, field emission devices, composites, chemical sensors, biosensors, detectors, etc. There are no CNT-based products currently on the market with mass market appeal, but some are in the making. In one sense, that is not surprising because time-to-market from discovery typically takes a decade or so. Given that typical time scale, most current endeavors are not even halfway down that path. The community is beginning to move beyond the wonderful properties that interested them in CNTs and are beginning to tackle real issues associated with converting a material into a device, a device into a system, and so on. At this point in the development phase of CNT-based applications, this book attempts to capture a snap shot of where we are now and what the future holds. Chapter 1 describes the structure and properties of carbon nanotubes — though well known and described in previous textbooks — both as an introduction and for the sake of completeness in a book like this one. In understanding the properties, the modeling efforts have been trailblazing and have uncovered many interesting properties, which were later verified by hard characterization experiments. For this reason, modeling and simulation are introduced early in Chapter 2. Chapter 3 is devoted to the two early techniques that produced single-walled nanotubes, namely, arc synthesis and laser ablation. Chemical vapor deposition (CVD) and related techniques (Chapter 4) emerged later as a viable alternative for patterned growth, though CVD was widely used in early fiber development efforts in the 1970s and 1980s. These chapters on growth are followed by a chapter devoted to a variety of imaging techniques and characterization (Chapter 5). Important techniques such as Raman spectroscopy are covered in this chapter. The focus on applications starts with the use of single-walled and multiwalled carbon nanotubes in scanning probe microscopy in Chapter 6. In addition to imaging metallic, semiconducting, dielectric, and biological surfaces, these probes also find applications in semiconductor metrology such as profilometry and scanning probe lithography. Chapter 7 summarizes efforts to date on making CNT-based diodes and transistors and attempts to explain the behavior of these devices based on well-known semiconductor device physics theories explained in undergraduate and graduate textbooks. It is commonly forecast that silicon CMOS device scaling based on Moore’s law may very well end in 10 or 15 years. The industry has been solving the technical problems in CMOS scaling impressively even as we embark on molecular electronics, as has been the case with the semiconductor industry in the past 3 decades. Therefore, for those pursuing alternatives such as CNT electronics and molecular electronics, the silicon electronics is a moving target and the message is clear: replacing silicon-conducting channel simply with a CNT-conducting channel in a CMOS may not be of much value — alternative architectures;different state variable (such as spin)-based systems; and coupling functions such as computing, memory, and sensing are what can set the challengers apart from the incumbent. Unfortunately, at the writing of this book, there is very little effort in any of these directions, and it is hoped that such alternatives emerge, succeed, and flourish. Field emission by carbon nanotubes is very attractive for applications such as flat panel displays, x-ray tubes, etc. The potential for commercial markets in television and computer monitors, cell phones, and other such displays is so enormous that this application has attracted not only much academic research but also substantial industrial investment. Chapter 8 discusses principles of field emission, processes to fabricate the emitters, and applications. One application in particular, making an x-ray tube, is covered in great detail from principles and fabrication to testing and characterization. With every atom residing on the surface in a single-walled carbon nanotube, a very small change in the ambient conditions can change the properties (for example, conductivity) of the nanotube. This change can be exploited in developing chemical sensors. The nanotubes are amenable to functionalization by attaching chemical groups, DNA, or proteins either on the end or sidewall. This also allows developing novel sensors using nanotubes. Chapter 9 discusses principles and development of chemical and physical sensors. Likewise, Chapter 10 describes biosensor development. The mechanical, thermal, and physical properties of carbon nanotubes have resulted in numerous studies on conducting polymer films, composites, and other structural applications. Chapter 11 captures these developments. Finally, all other applications that elude the above prime categories are summarized in Chapter 12. This is an edited volume, and various authors who practice the craft of carbon nanotubes day to day have contributed to this volume. I have made an effort to make this edited volume into a cohesive text. I hope that the readers — students and other researchers getting into this field, industry, and even the established experts — find this a valuable addition to the literature in carbon nanotubes. I would like to thank Nora Konopka of the CRC Press for her support throughout this work. Finally, this book would not have been possible without the help and skills of my assistant Amara de Keczer. I would like to thank her also for the cover design of the book.
Carbon nanotubes-properties and applications: a review
Carbon letters
The carbon nanotube (CNT) represents one of the most unique inventions in the field of nanotechnology. CNTs have been studied closely over the last two decades by many researchers around the world due to their great potential in different fields. CNTs are rolled graphene with hybridization. The important aspects of CNTs are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful as fillers in different materials such as polymers, metallic surfaces and ceramics. CNTs also have potential applications in the field of nanotechnology, nanomedicine, transistors, actuators, sensors, membranes, and capacitors. There are various techniques which can be used for the synthesis of CNTs. These include the arc-discharge method, chemical vaporize deposition (CVD), the laser ablation method, and the sol gel method. CNTs can be single-walled, double-walled and multi-walled. CNTs have unique mechanical, electrical and...
Preprint, 2021
Carbon nanotubes (CNTs), composed of graphene/graphite sheets, have been used since the 1990s and become one of the most important materials owing to its massive applications in energy, environmental and life sciences. In general, there are two types of known CNTs such as single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). They have broader and novel elds of application in the fabric and textile industries, wastewater treatment, energy storage, and also as structural reinforcement materials. CNTs are reported to synthesize by arc discharge, laser ablation and chemical vapor deposition (CVD) methods where CVD technique is found to be the most versatile and largely used method. In all the methods synthesized CNTs contain various degrees of impurities which are puri ed by oxidation treatment, ultra-sonication, magnetic puri cation, etc. CNTs have wide range of industrial applications due to their remarkable mechanical, thermal, electrical, chemical and biological properties. In this review, medical and biomedical applications of CNTs and CNTs-based composites are specially focused due to their signi cant applications in these elds along with their structure, classi cation, preparation and related properties. Besides, CNTs' toxicity and biosafety, especially on the human body, are also discussed in this review article.
CARBON NANOTUBES: SYNTHESIS, PROPERTIES AND TECHNOLOGICAL APLLICATIONS
This project reviews synthesis, properties and technological applications of carbon nanotubes. The different synthesis methods of carbon nanotubes are illustrated briefly. The energy dependence of density of states was used to determine the optical properties of CNT. Finally, brief description of optical and electronic properties was presented. Using MATLAB Code the theoretical simulation of electronic band structure as a function of wave vector, the band gap as a function of tube diameter and the density of state as a function of energy band are generated.
An Overview on Carbon Nanotubes
2012
ABSTRACT: In different fields like semiconductors, field emission, conductive plastics, energy storage, conductive adhesives and connectors, molecular electronics, thermal materials carbon nanotubes are applicable. Carbon nanotubes are generally produced by three main techniques: arc discharge, laser ablation, chemical vapour deposition. In arc discharge, a vapour is created by an arc discharge between two carbon electrodes with or without catalyst. Nanotubes self-assemble from the resulting carbon vapour. In the laser ablation technique, a high-power laser beam impinges on a volume of carbon -containing feedstock gas (methane or carbon monoxide). At the moment, laser ablation produces a small amount of clean nanotubes, whereas arc discharge methods generally produce large quantities of impure material. In general, chemical vapour deposition (CVD) results in Multi Walled Nanotubes or poor quality Single Walled Nanotubes. The SWNTs produced with CVD have a large diameter range, which...
A Review on Carbon Nanotubes: Preparation, Properties and Applications
Journal of Research Updates in Polymer Science, 2020
Carbon nanotubes(CNTs) have achieved attention in recent times because of their extraordinary physicochemical properties like strength, flexibility, sensors, conducting etc. Carbon nanotubes(CNTs) are known as nano-architectured allotropes of carbon, having graphene sheets which are rolled up into cylinder that forms carbon nanotubes. In the field of nanotechnology, carbon nanotubes are the one of the most unique invention. The eye-catching features of carbon nanotubes are their electronic, mechanical, optical and chemical characteristics, which open a way to future applications. Carbon nanotubes can be single walled and multi walled which can be produced in various ways. The most common techniques used nowadays are: arc discharge, laser ablation and chemical vapour deposition. In this review article,the applications of CNTs in various technologically important fields are discussed in detail.