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Über dieses Buch

This comprehensive handbook has become the definitive reference work in the field of nanoscience and nanotechnology, and this 4th edition incorporates a number of recent new developments.

It integrates nanofabrication, nanomaterials, nanodevices, nanomechanics, nanotribology, materials science, and reliability engineering knowledge in just one volume. Furthermore, it discusses various nanostructures; micro/nanofabrication; micro/nanodevices and biomicro/nanodevices, as well as scanning probe microscopy; nanotribology and nanomechanics; molecularly thick films; industrial applications and nanodevice reliability; societal, environmental, health and safety issues; and nanotechnology education.

In this new edition, written by an international team of over 140 distinguished experts and put together by an experienced editor with a comprehensive understanding of the field, almost all the chapters are either new or substantially revised and expanded, with new topics of interest added. It is an essential resource for anyone working in the rapidly evolving field of key technology, including mechanical and electrical engineers, materials scientists, physicists, and chemists.

Inhaltsverzeichnis

Frontmatter

1. Introduction to Nanotechnology

Nanotechnology refers to technology that is implemented at the nanoscale and has applications in the real world. Unique physical and chemical properties of nanomaterials can be exploited for applications that benefit society. Nanotechnology represents a

megatrend

and has become a

general purpose

technology. An executive action of 2000, the National Nanotechnology Initiative was formalized with the 21st Century Nanotechnology Research and Development Act in 2003. Through FY 2015 in the United States, federal R&D investment has been about $20 billion, with annual investment in FY 2015 of about $1.5 B, and more than double that by the private sector. The revenues from nanoenabled products continue growing, with over $200 B in FY 2012 in the US alone, and over $700 B worldwide. This represents an impressive return on investment. Basic research and development as well as research on potential safety issues of nanotechnology, workforce development, and education and curriculum should be continued.

A biological system can be exceedingly small. Many of the cells are very tiny, but they are very active; they manufacture various substances; they walk around; they wiggle; and they do all kinds of marvelous things – all on a very small scale. Also, they store information. Consider the possibility that we too can make a thing very small which does what we want – that we can manufacture an object that maneuvers at that level.

R.P. Feynman: There's Plenty of Room at the Bottom. In:

Annu. Meet. Am. Phys. Soc. California Institute of Technology, Pasadena

(1959)

Bharat Bhushan

Micro/Nanofabrication Techniques

Frontmatter

2. Molecule-Based Devices

The constituent components of conventional devices are carved out of larger materials relying on physical methods. This top-down approach to engineered building blocks becomes increasingly challenging as the dimensions of the target structures approach the nanoscale. Nature, on the other hand, assembles nanoscaled biomolecules relying on chemical strategies. Small molecular building blocks are joined to produce nanostructures with defined geometries and specific functions. It is becoming apparent that Nature's bottom-up approach to functional nanostructures can be mimicked to produce artificial molecules with nanoscaled dimensions and engineered properties. Indeed, examples of artificial nanohelicesnanohelix, nanotubesnanotube (NT) and molecular motors are starting to be developed. Some of these fascinating chemical systems have intriguing electrochemical and photochemical properties, which can be exploited to manipulate chemical, electrical and optical signals at the molecular level. This tremendous opportunity has led to the development of the molecular equivalent of conventional logic gates. Indeed, simple logic operations can be reproduced with collections of molecules operating in solution. Most of these chemical systems, however, rely on bulk addressing to execute combinational and sequential logic operations. It is essential to devise methods to reproduce these useful functions in solid-state configurations and, eventually, with single molecules. These challenging objectives are stimulating the design of clever devices that interface small assemblies of organic molecules with macroscaled and nanoscaled electrodes. These strategies have already produced rudimentary examples of diodes, switches and transistors based on functional molecular components. The rapid and continuous progress of this exploratory research will, hopefully, lead to an entire generation of molecule-based devices that might ultimately find useful applications in a variety of fields ranging from biomedical research to information technology.

Françisco M. Raymo

3. Introduction to Micro-/Nanofabrication

This chapter outlines and discusses important micro- and nanofabrication techniques. We focus on the most basic methods borrowed from the integrated circuit (ICintegratedcircuit (IC)) industry, such as thin-film deposition, lithography and etching, and then move on to look at microelectromechanical systems (MEMSmicroelectromechanical system (MEMS)) and nanofabrication technologies. We cover a broad range of dimensions, from the sub-millimeter to the nanometer scale. Although most of the current research is being geared towards the nanodomain, a good understanding of basic top-down methods for fabricating micron-sized objects can aid our understanding of this research. Due to space constraints, we focus here on the most important technologies; in the microdomain these include surface, bulk, and high-aspect-ratio micromachining; in the nanodomain we concentrate on e-beam lithography, epitaxial growth, scanning probe lithography, template manufacturing, and self-assembly. MEMS technology has matured rapidly, with some new technologies displacing older ones that have proven to be unsuited to manufacture on a commercial scale. However, due to limitations encountered on these methods used in the nanodomain, it appears that bottom-up methods or introduction of novel nanoforms and nanomaterials are the most feasible and promising solutions. Disruptive approaches are expected to have a major impact in a variety of application areas such as biology, medicine, environmental monitoring, and nanoelectronics.

Gemma Rius, Antoni Baldi, Babak Ziaie, Massood Z. Atashbar

4. 3-D Nanostructure Fabrication by Focused-Ion Beam, Electron- and Laser Beam

In this chapter, we describe three-dimensional (3-Dthree-dimensional (3-D)) nanostructure fabrication techniques using focused-ion-beam (FIBfocused ion beam (FIB))-induced chemical vapor deposition (CVDchemical vapor deposition (CVD)), electron-beam (EBelectron beam)-induced CVD, and femtosecond laser (fs-laserfemtosecond laser (fs-laser)) techniques. We first describe 30 keV Ga+ FIB-induced CVD using a phenanthrene (C14H10) source gas as the precursor. A diamond-like amorphous carbon film is deposited during this process; it has a Young's modulus exceeding 600 GPa, making it potentially highly desirable for various applications. A three-dimensional pattern generator system has been developed to make arbitrary three-dimensional nanostructures. We also discuss microstructure plastic art, which is a new field that has been made possible by microbeam technology, and we present examples of such art, including a micro wine glass with an external diameter of 2.75 μm and a height of 12 μm. We then discuss free-space nanowiring and show by using a mixture of C14H10 and W ( CO)6 that the electrical properties indicate an increase in metal content results in a lower resistivity. We also demonstrate that a Morpho butterfly scale quasistructure fabricated by FIB-induced CVD has almost the same optical characteristics as a real Morpho butterfly scale. We then discuss three-dimensional nanostructure fabrication using EB-induced CVD. Because of the nanometer resolution, EB-induced CVD is now indispensable for mask repair techniques for the 193 nm node. According to real-time observations by transmission electron microscopy, the W clusters, as the initial growth stage, are formed first followed by the W layer which forms as W clusters coalesce due to EB irradiation. We go on to discuss photonic crystals and Smith–Purcell electron optics as examples of three-dimensional nanostructure applications using EB-induced CVD. Finally, we describe femtosecond-laser-assisted micro/nano fabrication which has been recognized as a promising technique to fabricate three-dimensional structures inside transparent materials. The spatial resolution can reach submicrometer levels and even tens of nanometers owing to suppression of the involved heat diffusion and nonlinear adsorption. We discuss three-dimensional femtosecond laser nanofabrication using the direct laser writing technique and multiple beam interference lithography and describe the fabrication of photonic crystals in a photoresist.

Shinji Matsui, Hiroaki Misawa, Quan Sun

5. Nanoimprint Lithography

Nanoimprint lithography (NILnanoimprint lithography (NIL)lithographynanoimprint (NIL)) is an emerging high-resolution parallel patterning method, mainly aimed towards fields in which electron-beam and high-end photolithography are costly and do not provide sufficient resolution at reasonable throughput. In a top-down approach, a surface pattern of a stamp is replicated in a material by mechanical contact and three-dimensional material displacement. This can be done by shaping a liquid followed by a curing process for hardening, by variation of the thermomechanical properties of a film by heating and cooling, or by any other kind of shaping process using the difference in hardness of a mold and a moldable material. The local thickness contrast of the resulting thin molded film can be used as a means to pattern an underlying substrate at the wafer level by standard pattern transfer methods, but also directly in applications where a bulk modified functional layer is needed. This makes NIL a promising technique for high-volume manufacturing of nanostructured components. At present, structures with feature sizes smaller than 5 nm have been realized, and the resolution is limited by the ability to manufacture the stamp relief. For historical reasons, the term nanoimprint lithography refers to a hot embossing process (thermal NIL). In ultraviolet (UVultraviolet (UV)) NIL, a photopolymerizable resin is used together with a UV-transparent stamp. In both processes thin-film squeeze flow and capillary action play a central role in understanding the NIL process. In this chapter we will give an overview of NIL, with emphasis on general principles and concepts rather than specific process issues and state-of-the-art tools and processes. Material aspects of stamps and resists are discussed. Specific applications are presented, where imprint methods have significant advantages over other structuring methods. We conclude by discussing the areas where further development in this field is required.

Helmut Schift, Anders Kristensen

6. Stamping Techniques for Micro- and Nanofabrication

Soft-lithographic techniques that use rubber stamps and molds provide simple means to generate patterns with lateral dimensions that can be much smaller than 1 μm and can even extend into the single nanometer regime. These methods rely on the use of soft elastomeric elements typically made out of the polymer poly(dimethylsiloxane). The first section of this chapter presents the fabrication techniques for these elements together with data and experiments that provide insights into the fundamental resolution limits. Next, several representative soft-lithography techniques based on the use of these elements are presented:1.Microcontact printing, which uses molecular inks that form self-assembled monolayers.2.Near- and proximity-field photolithography for producing two- and three-dimensional structures with subwavelength resolution features.3.Nanotransfer printing, where soft or hard stamps print single or multiple layers of solid inks with feature sizes down to 100 nm.The chapter concludes with descriptions of some device-level applications that highlight the patterning capabilities and potential commercial uses of these techniques.

John A. Rogers, Etienne Menard

7. Materials Aspects of Micro- and Nanoelectromechanical Systems

One of the more significant technological achievements during the last twenty years has been the development of the field of microelectromechanical systems (MEMSmicroelectromechanical system (MEMS)) and its offshoot, nanoelectromechanical systems (NEMSnanoelectromechanical system (NEMS)). These developments were made possible by significant advancements in the materials and processing technologies used in the fabrication of MEMS and NEMS devices. While initial developments capitalized on a mature Si infrastructure built for the integrated circuit (ICintegratedcircuit (IC)) industry, recent advances have come about using materials and processes not typically associated with IC fabrication, a trend that is likely to continue as new application areas emerge.A well-rounded understanding of MEMS and NEMS technology requires a basic knowledge of the materials used to construct the devices, since material properties often govern device performance and dictate fabrication approaches. An understanding of the materials used in MEMS and NEMS involves an understanding of material systems, since such devices are rarely constructed of a single material, but rather a collection of materials working in conjunction with each other to provide critical functions. It is from this perspective that the following chapter is constructed. This chapter is not a summary of all materials used in MEMS and NEMS, as such a work would itself constitute a single text of significant size. It does, however, present a selection of some of the more popular materials, as well as those that illustrate the importance of viewing MEMS and NEMS in terms of material systems.

Christian A. Zorman

Nanomaterials and Nanostructures

Frontmatter

8. Carbon Nanotubes

Carbon nanotubes (CNTcarbon nanotube (CNT)s) are remarkable objects that once looked set to revolutionize the technological landscape in the near future. Since the 1990s and for twenty years thereafter, it was repeatedly claimed that tomorrow's society would be shaped by nanotube applications, just as silicon-based technologies dominate society today. Space elevators tethered by the strongest of cables, hydrogen-powered vehicles, artificial muscles: these were just a few of the technological marvels that we were told would be made possible by the science of carbon nanotubes.Of course, this prediction is still some way from becoming reality; most often the possibilities and potential have been evaluated, but actual technological development is facing the unforgiving rule that drives the transfer of a new material or a new device to market: profitability. New materials, even more so for nanomaterials, no matter how wonderful they are, have to be cheap to produce, constant in quality, easy to handle, and nontoxic. Those are the conditions for an industry to accept a change in its production lines to make them nanocompatible. Consider the example of fullerenes – molecules closely related to nanotubes. The anticipation that surrounded these molecules, first reported in 1985, resulted in the bestowment of a Nobel Prize for their discovery in 1996. However, two decades later, very few fullerene applications have reached the market, suggesting that similarly enthusiastic predictions about nanotubes should be approached with caution, and so should it be with graphene, another member of the carbon nanoform family which joined the game in 2004, again acknowledged by a Nobel Prize in 2010.There is no denying, however, that the expectations surrounding carbon nanotubes are still high, because of specificities that make them special compared to fullerenes and graphene: their easiness of production, their dual molecule/nano-object nature, their unique aspect ratio, their robustness, the ability of their electronic structure to be given a gap, and their wide typology etc. Therefore, carbon nanotubes may provide the building blocks for further technological progress, enhancing our standard of living.In this chapter, we first describe the structures, syntheses, growth mechanisms, and properties of carbon nanotubes. Then we introduce nanotube-based materials, which comprise on the one hand those formed by reactions and associations of all-carbon nanotubes with foreign atoms, molecules and compounds, and on the other hand, composites, obtained by incorporating carbon nanotubes in various matrices. Finally, we will provide a list of applications currently on the market, while skipping the potentially endless and speculative list of possible applications.

Marc Monthioux, Philippe Serp, Brigitte Caussat, Emmanuel Flahaut, Manitra Razafinimanana, Flavien Valensi, Christophe Laurent, Alain Peigney, David Mesguich, Alicia Weibel, Wolfgang Bacsa, Jean-Marc Broto

9. Nanowires

This chapter provides an up-to-date overview of research on inorganic nanowires, particularly metallic and semiconducting nanowires. Nanowires are one-dimensional, anisotropic structures, small in diameter, and large in surface-to-volume ratio. Their physical properties are different than those of structures of other scales and dimensionality. While the study of nanowires is particularly challenging, scientists have made immense progress in developing synthetic methodologies for the fabrication of nanowires, developing instrumentation for their characterization, and incorporating nanowires as functional elements in advanced materials and devices. The chapter is divided into three main sections addressing the synthesis, the physical properties, and the applications of nanowires. Yet, the reader will discover many links that make these aspects of nanoscience intimately interdependent.

Mildred S. Dresselhaus, Marcie R. Black, Vincent Meunier, Oded Rabin

10. Nanoribbons

Graphene nanoribbons have intriguing electronic structures, which are large edge geometry dependent. Armchair-edged graphene nanoribbons, which are energetically stable, have a ribbon-width-dependent intrinsic energy gap, while zigzag-edged ones have spin-polarized nonbonding edge states in the vicinity of the edge region. The edge state is the origin of electronic, magnetic and chemical activities. These features of the electronic structures can be characterized using microprobe techniques such as scanning tunneling microscopy/spectroscopy (STMscanningtunneling microscopy (STM)/STSscanningtunneling spectroscopy (STS)), atomic force microscopy (AFMatomic force microscopy (AFM)), transmission electron microscopy (TEMtransmission electron microscopy (TEM)), Raman spectroscopy, x-ray absorption, angle-resolved photoemission spectroscopy, electron transport, and magnetic measurements. Graphene nanostructures are synthesized using top-down and bottom-up methods, in the latter of which graphene nanostructures with atomically precise edges can be created. The presence of bandgap, which varies depending on the ribbon width and the edge geometry, makes graphene an important candidate for electronics device applications. The spin-polarized edge states localized in the vicinity of edges in zigzag-edged nanoribbons are expected to be utilized for spintronics applications.

Toshiaki Enoki, Shintaro Sato

11. Nanoparticles and Their Applications

Nanoparticles (NPnanoparticle (NP)s) are synthesized from several classes of materials including inorganic, organic, hybrid and biological materials. Inorganic NPs are synthesized by ball milling, vapor deposition, electrospraying, reduction of metal salts, sol-gel, coprecipitation and thermal decomposition. Organic NPs are synthesized by microemulsion, nanoprecipitation, dialysis and rapid expansion of supercritical solutions. Hybrid NPs are synthesized from both organic and inorganic materials. There are a number of naturally occurring biological NPs including lipoproteins, exosomes, ferritin, and viruses. Further, NPs can be synthesized from biomolecules including proteins, peptides and polysaccharides. The surface to volume ratio, superparamagnetism, hardness, Coulomb energy and catalytic activity of NPs are generally higher than those of bulk materials. Due to their unique structural, magnetic, mechanical and electrical properties, NPs are used in a wide range of applications including biosensing, drug delivery, bioimaging, catalysis, nanomanufacturing, lubrication, electronics, textile manufacturing, and water treatment systems. This chapter covers the classification, synthesis, properties and applications of NPs.

Seyedsina Moeinzadeh, Esmaiel Jabbari

12. Graphene

Graphenegraphene is the two-dimensional allotrope of carbon, consisting of a hexagonal arrangement of carbon atoms on a single plane. This chapter begins with a brief history of graphene, followed by a discussion of different methods to produce graphene. The atomic and electronic structure of graphene is then described. The intrinsic properties of graphene can be tailored by nanofabrication, chemistry, electromagnetic fields, etc. Various applications of graphene have been proposed in electronic, optoelectronic and mechanical products. In addition, graphene has emerged as a candidate in chemical, biochemical and biological applications. Derivatives of graphene such as graphene oxide or graphane are also of interest both in terms of fundamental properties and applications.

Aravind Vijayaraghavan, Maria Iliut

MEMS/NEMS

Frontmatter

13. MEMS/NEMS Devices and Applications

Microelectromechanical microelectromechanical system (MEMS)systems (MEMS) have played key roles in many important areas, for example, transportation, communication, automated manufacturing, environmental monitoring, healthcare, defense systems, and a wide range of consumer products. MEMS are inherently small, thus offering attractive characteristics such as reduced size, weight, and power dissipation and improved speed and precision compared to their macroscopic counterparts. Integrated circuits (ICintegratedcircuit (IC)fabrication technologynanoelectromechanical system (NEMS)) fabrication technology has been the primary enabling technology for MEMS besides a few special etching, bonding and assembly techniques. Microfabrication provides a powerful tool for batch processing and miniaturizing electromechanical devices and systems to a dimensional scale that is not accessible by conventional machining techniques. As IC fabrication technology continues to scale toward deep submicrometer and nanometer feature sizes, a variety of nanoelectromechanical systems (NEMS) have been rapidly emerging. Nanoscale mechanical devices and systems integrated with nanoelectronics will open a vast number of new exploratory research areas in science and engineering. NEMS will most likely serve as an enabling technology, merging engineering with the fundamental physics, quantum science, and life sciences in ways that are not currently feasible with microscale tools and technologies.MEMS has been applied to a wide range of fields. Hundreds of microdevices have been developed for specific applications. It is thus difficult to provide an overview covering every aspect of the topic. In this chapter, key aspects of microelectromechanical system (MEMS)MEMS technology and applications are illustrated by selecting a few demonstrative device examples, such as pressure sensors, inertial sensors, optical and wireless communication devices. Microstructure examples with dimensions on the order of submicrometer are presented with fabrication technologies for emerging NEMS applications.Although MEMS has experienced significant growth over the past decade, many challenges still remain. In broad terms, these challenges can be grouped into three general categories: (1) fabrication challenges; (2) packaging challenges; and (3) application challenges. Challenges in these areas will, in large measure, determine the commercial success of a particular MEMS device in both technical and economic terms. This chapter presents a brief discussion of some of these challenges as well as possible approaches to addressing them.

Philip X.-L. Feng, Darrin J. Young, Christian A. Zorman

14. Single-Walled Carbon Nanotube Sensor Concepts

Carbon nanotubes are excellent nanocomponents that offer unique properties that can be exploited in next-generation devices. Sensing applications is perhaps the class that has most to gain from single-walled carbon nanotubes (SWNTsingle-walled (carbon) nanotube (SWNT)carbon nanotube (CNT)single-wall (SWNT)s); virtually any property of SWNTs, such as electronic, electrical, mechanical and optical, can result or has already resulted in sensor concept demonstrators. The basic questions this chapter will attempt to address are, why use SWNTs? and how can SWNTs be used? in sensing applications. A tour through the gallery of basic nanotube properties is given in order to reveal the richness and uniqueness of this material's intrinsic properties. Together with examples from the literature, showing performance of SWNT-based sensors at least comparable to – but oftentimes surpassing – state-of-the-art micro- or macrodevices, nanotube properties should explain why there is so much effort currently being invested in this field. As nanotubes, like any other nano-object, are not easy to probe, a versatile strategy for accessing their properties, via the carbon nanotube field-effect transistor (CNFETcarbon nanotube (CNT)field-effect transistor (CNFET)) concept, will be described in this chapter. Furthermore, descriptions of CNFET device fabrication together with examples of SWNT sensor demonstrators utilizing the CNFET principle will be followed by proposals of how nanotubes can be utilized in sensors.

Cosmin I. Roman, Thomas Helbling, Miroslav Haluška, Christofer Hierold

15. Nanomechanical Cantilever Array Sensors

In recent years, mechanics has experienced a revival, as microfabrication technologies and nanotechnology are applied to produce tiny structures. The development of ultraprecise position sensing started three decades ago with a novel imaging technique called atomic force microscopy, which provides ultrahigh topography resolution on the atomic scale by raster-scanning the surface with a microfabricated cantilever beam that has a tiny tip at its free end. The high force sensitivity can not only be used for imaging, but also allows the measurement of surface forces during molecule adsorption processes on the cantilever surface, thus enabling cantilevers to act as chemical sensors. Because of their small size, cantilevers allow fast and reliable detection of small concentrations of molecules in air and solution. In addition to artificial nose and label-free biosensing applications, they have also been employed to measure physical properties of tiny amounts of materials in miniaturized versions of conventional standard techniques such as calorimetry, thermogravimetry, weighing, photothermal spectroscopy and monitoring of chemical reactions. In the past few years, the cantilever-sensor concept has been extended to medical applications and has entered clinics for pilot studies on patients. The small size and scalability of cantilever array sensors might turn out to be advantageous for diagnostic screening applications and disease monitoring, as well as for genomics or proteomics. Using microcantilever arrays allows simultaneous detection of several analytes and solves the inherent problem of thermal drifts often present when using single microcantilever sensors, as some of the cantilevers can be used as sensor cantilevers for detection, and others as passivated reference cantilevers that do not show affinity to the molecules to be detected.

Hans Peter Lang, Martin Hegner, Christoph Gerber

16. Microfluidic Devices and Their Applications

Microfluidics and nanofluidics is a field of science that operates in the micrometer and nanometer scale. A microfluidic–nanofluidic device consists of components such as valves, pumps and mixers for manipulating and transporting the fluid at this scale. In this chapter we review the history, physics, fabrication methods and applications of microfluidics and nanofluidics. This interdisciplinary field has a wide range of application areas including environmental sensing, medical diagnostics, drug discovery, drug delivery, microscale chemical production, combinatorial synthesis and assays, artificial organs, and micropropulsion, microscale energy systems. The global market for microfluidic devices was estimated at around $3.1 billion dollars in 2015 and is expected to rise to $7.5 billion dollars by 2020. In the future, microfluidics and nanofluidics will see miniaturization and development of novel microfabrication techniques along with more sensitive detection methods and diagnosis of diseases in a point-of-care platform. Developments in the fundamental physics of fluid flow and its control, microfabrication methods, microfluidic components, and applications in new and emerging areas are all anticipated.

Aditya Aryasomayajula, Pouriya Bayat, Pouya Rezai, P. Ravi Selvaganapathy

17. Microfluidic Micro/Nano Droplets

Microfluidic droplet technology has evolved rapidly since the first microfluidic droplet generator was reported over a decade ago. It has subsequently branched out and emerged as a practical solution to enhance the capabilities of many other fields, including, but not limited to: high-throughput screening, biosensing, drug delivery and synthetic biology. In this chapter, we will report on recent advancements in droplet microfluidic technologies that have emerged since Teh et al.'s comprehensive 2007 review. We begin with a brief history of droplet microfluidics and introduce methods of droplet production, manipulation, and sensing methodologies. The remainder of the chapter is dedicated to design considerations for various droplet production configurations, concluding with a discussion on applications, trends and the general direction that the field is headed.

Gopakumar Kamalakshakurup, Derek Vallejo, Abraham Lee

18. Nanorobotics

Nanoroboticsnanorobotics is the study of roboticsrobotics at the nanometer scale, and includes robots that are nanoscale in size and large robots capable of manipulating objects that have dimensions in the nanoscale range with nanometer resolution. With the ability to position and orient nanometer-scale objects, nanorobotic manipulation is a promising way to enable the assembly of nanosystems including nanorobots.This chapter overviews the state of the art of nanorobotics, outlines nanoactuation, and focuses on nanorobotic manipulation systems and their application in nanoassembly, biotechnology and the construction and characterization of nanoelectromechanical systems (NEMSnanoelectromechanical system (NEMS)nanoelectromechanical system (NEMS)) through a hybrid approach.Because of their exceptional properties and unique structures, carbon nanotubes (CNTcarbon nanotube (CNT)carbon nanotube (CNT)s) and SiGe/Si nanocoils are used to show basic processes of nanorobotic manipulation, structuring and assembly, and for the fabrication of NEMS including nano tools, sensors and actuators.A series of processes of nanorobotic manipulation, structuring and assembly has been demonstrated experimentally. Manipulation of individual CNTs in three-dimensional (3-Dthree-dimensional (3-D)nanofabricationbionanotechnologynanoelectronic) free space has been shown by grasping using dielectrophoresis and placing with both position and orientation control for mechanical and electrical property characterization and assembly of nanostructures and devices. A variety of material property investigations can be performed, including bending, buckling, and pulling to investigate elasticity as well as strength and tribological characterization. Structuring of CNTs can be performed including shape modification, the exposure of nested cores, and connecting CNTs by van der Waals forces, electron-beam-induced deposition and mechanochemical bonding. Nanorobotics provides novel techniques for exploring the biodomain by manipulation and characterization of nanoscale objects such as cellular membranes, DNA and other biomolecules. Nano tools, sensors and actuators can provide measurements and/or movements that are calculated in nanometers, gigahertz, piconewtons, femtograms, etc., and are promising for molecular machines and bio- and nanorobotics applications. Efforts are focused on developing enabling technologies for nanotubes and other nanomaterials and structures for NEMS and nanorobotics. By combining bottom-up nanorobotic manipulation and top-down nanofabrication processes, a hybrid approach is demonstrated for creating complex 3-D nanodevices. Nanomaterial science, bionanotechnology, and nanoelectronics will benefit from advances in nanorobotics.

Bradley J. Nelson, Lixin Dong

BioMEMS/NEMS

Frontmatter

19. Applications of MEMS to Cell Biology

Relatively simple microscale devices such as cantilevers already have found distinct applications in the study of cells and subcellular structures. The ability to measure small forces, small features, and small masses has led to unique and elegant measurement solutions. In this chapter, we give a brief background of some relevant fundamental biology and provide examples of research in cell biology, ranging from mechanobiology, physiology, microbiology to cancer biology, where MEMS- and NEMS-based methods have had a significant and, most likely, lasting impact.

Georg E. Fantner, Pascal D. Odermatt, Haig Alexander Eskandarian

20. Contact-free Mechanical Manipulation of Biological Materials

In biotechnology and medicine, controlled studies on biological material are fundamental for developing new methodologies and therapeutic approaches. To explore the nature of biological processes and to test inherent material properties, it has become increasingly clear that new experimental methods must be developed in order to allow precise manipulations and quantification of biological materials on the microscopic level. Traditional methods often rely on physical contact with the sample, which can induce drastic artifacts in soft biological systems. To bypass this limitation, tools for contact-free manipulation were developed, which even enable the induction of whole-cell deformations to explore their mechanical properties. These approaches facilitate extensive investigations of single molecules, molecular ensembles, cells and even tissues, potentially reducing the need for animal studies. In this rapidly changing field, it is nearly impossible to provide a comprehensive overview of all available techniques since new methods are constantly being developed. In this chapter, we highlight many of the predominant approaches, aiming to investigate cellular as well as subcellular mechanical properties and processes.

Jörg Schnauß, Josef A. Käs, David M. Smith

21. Nano-Particles for Biomedical Applications

Nanoparticles (NPnanoparticle (NP)s) are extremely small particulates with an average size that ranges from a micron or less to a few nanometers. The large majority of NPs necessitate nanotechnology methods for their production. The size of NPs may vary over a significant range, which underlies their scientific potential in that NPs may help cross the bridge between bulk materials and molecular structures. More importantly, NPs are (nano)tech products and thus, in contrast to natural systems, they can be designed and engineered. On directly interacting with cells, including the structures of cells, their machinery and their waste products, NPs represent an unprecedented tool for addressing specific biological problems. In this chapter, we will briefly review some recent advances in nanoparticle research for biomedical applications, ranging from mesoporous silicon particles to gold and silver nanoparticles and polymeric nanocarriers for therapeutic, diagnosis, or theranostic (therapeutics + diagnosis) applications. We will offer a description of how, at the current state of the art, similar nanomedicine platforms are realized.

Paolo Decuzzi, Alessandro Coclite, Aeju Lee, Anna Lisa Palange, Daniele Di Mascolo, Ciro Chiappini, Hélder A. Santos, Maria Laura Coluccio, Gerardo Perozziello, Patrizio Candeloro, Enzo Di Fabrizio, Francesco Gentile

22. Biological Molecules in Therapeutic Nanodevices

In this chapter, we discuss the incorporation of molecules into therapeutic nanodevicenanodevices as functional device components. Our primary focus is on biological molecules, although we also discuss the use of organic molecules nanodevicesupramolecularas functional components of supramolecular nanodevices. Our primary device interest is in devices used in human therapy and diagnosis, though when it is informative, we discuss other nontherapeutic nanodevices containing biomolecular components. We discuss design challenges associated with devices built from prefabricated components (biological macromolecules) but that are not as frequently associated with fully synthetic nanodevices. Some design challenges (abstraction of device object properties, inputs, and outputs) can be addressed using existing systems engineering approaches and tools (including unified modeling language), whereas others (selection of optimal biological macromolecules from the billions available) have not been fully addressed. We discuss various assembly strategies applicable to biological macromolecules and organic molecules (self-assembly, chemoselective conjugation) and their advantages and disadvantages. We provide an example of a functional mesoscale device, a planar field-effect transistor (FETfield-effect transistor (FET)field-effect transistor (FET)protein sensingmolecularengineeringnanoscaleprotein interface) protein sensor, that depends on nanoscale components for its function. We also use the sensor platform to illustrate how protein and other molecular engineering approaches can address nanoscale technological problems, and argue that protein engineering is a legitimate nanotechnology in this application. In developing the functional FET sensor, both direct adsorption of protein analyte receptors as well as linkage of receptors to the sensing surface through a polymer layer were tested. However, in the realized FET sensor, interfaces consist of a polymer layer linked to the semiconductor surface and to an analyte receptor (a protein). Nanotribology and other surface-science investigations of the interfaces revealed phenomena not previously documented for nanoscale protein interfaces (lubrication by directly adsorbed proteins, increases in friction force associated with polymer-mediated increases in sample compliance). Furthermore, the studies revealed wear of polymer and receptor proteins from semiconductor surfaces by an atomic force microscopy (AFMatomic force microscopy (AFM)proteinsensorplanar immunoFETimmunoFETplanarinterfacialengineering) tip which was not a concerted process, but rather depth of wear increased with increasing load on the cantilever. These studies also revealed that the polymer–protein interfaces were disturbed by nanonewton forces, suggesting that interfaces of immunoFET protein sensors translated to in vivo use must likely be protected from, or hardened to endure, abrasion from tissue. The results demonstrate that nanoscience (in this case, nanotribology) is needed to design and characterize functional planar immunoFET sensors, even though the sensors themselves are mesoscale devices. The results further suggest that modifications made to the sensor interfaces to address these nanoscale challenges may be best accomplished by protein and interfacial engineering approaches.

Stephen C. Lee, Bharat Bhushan

Nanometrology

Frontmatter

23. Scanning Probe Microscopy — Principle of Operation, Instrumentation and Probes

Since the introduction of the Scanning Tunneling Microscope (STM) in 1981 and Atomic Force Microscope (AFM) in 1985, many variations of probe-based microscopies, referred to as Scanning Probe Microscopes (SPM), have been developed. While the pure imaging capabilities of SPM techniques are dominated by the application of these methods at their early development stages, the physics of probe-sample interactions and the quantitative analyses of tribological, electronic, magnetic, biological, and chemical surfaces have now become of increasing interest. In this chapter, we introduce various STM and AFM designs, various operating modes, various probes (tips), and AFM instrumentation and analyses.

Bharat Bhushan, Othmar Marti

24. Low-Temperature Scanning Probe Microscopy

This chapter is dedicated to scanning probe microscopy (SPMscanningprobe microscopy (SPM)) operated at cryogenic temperatures, where the more fundamental aspects of phenomena important in the fields of nanoscience and nanotechnology can be investigated with high sensitivity under well-defined conditions. In general, scanning probe techniques allow the measurement of physical properties down to the nanometer scale. Some techniques, such as scanning tunneling microscopy (STMscanningtunneling microscopy (STM)) and scanning force microscopy (SFMscanningforce microscopy (SFM)), even go down to the atomic scale. Various properties are accessible. Most importantly, one can image the arrangement of atoms on conducting surfaces by STM and on insulating samples by SFM. However, electronic states (scanning tunneling spectroscopy), force interaction between different atoms (scanning force spectroscopy), magnetic domains (magnetic force microscopy), magnetic exchange interactions (magnetic exchange force microscopy and spectroscopy), local capacitance (scanning capacitance microscopy), local contact potential differences (Kelvin probe force microscopy), local temperature (scanning thermal microscopy), and local light-induced excitations (scanning near-field microscopy) can also be measured with high spatial resolution, among others. In addition, some modern techniques even allow the controlled manipulation of individual atoms/molecules and the visualization of the internal structure of individual molecules. Moreover, combined STM/SFM experiments are now possible, mainly thanks to the advent of tuning forks as sensing elements in low-temperature (LT) SPM systems.Probably the most important advantage associated with the low-temperature operation of scanning probes is that it leads to a significantly better signal-to-noise ratio than measuring at room temperature. This is why many researchers work below 100 K. However, there are also physical reasons to use low-temperature equipment. For example, visualizing the internal structure of molecules with SFM or the utilization of scanning tunneling spectroscopy with high energy resolution can only be realized at low temperatures. Moreover, some physical effects such as superconductivity or the Kondo effect are restricted to low temperatures. Here, we describe the advantages of low-temperature scanning probe operation and the basics of related instrumentation. Additionally, some of the important results achieved by low-temperature scanning probe microscopy are summarized. We first focus on the STM, giving examples of atomic manipulation and the analysis of electronic properties in different material arrangements, among others. Afterwards, we describe results obtained by SFM, reporting on atomic-scale and submolecular imaging, as well as three-dimensional (3-Dthree-dimensional (3-D)) force spectroscopy. Results obtained with the method of Kelvin probe force microscopy (KPFMKelvin probe force microscopy (KPFM)) that is used to study variations in local contact potential difference (LCPDlocalcontact potential difference (LCPD)) are briefly discussed. Magnetic force microscopy (MFMmagneticforce microscopy (MFM)), magnetic exchange force microscopy (MExFMmagneticexchange force microscopy (MExFM)), and magnetic resonance force microscopy (MRFMmagneticresonance force microscopy (MRFM)) are also introduced. Although the presented selection of results is far from complete, we feel that it gives an adequate impression of the fascinating possibilities of low-temperature scanning probe instruments.In this chapter low temperatures are defined as lower than about 100 K and are normally achieved by cooling with liquid nitrogen or liquid helium. Applications in which SPMs are operated close to 0∘C are not covered in this chapter.

Mehmet Z. Baykara, Markus Morgenstern, Alexander Schwarz, Udo D. Schwarz

25. Biomedical Sensing with the Atomic Force Microscope

In this chapter we highlight the use and advantages of the atomic force microscope (AFMatomic force microscopy (AFM)) in life science. Our aim is to present the wealth of experimental possibilities provided by this powerful toolbox with special regard to biomedical sensing applications. Originally invented in the 1980s to visualize solid surfaces on the nanometer scale, today AFM imaging is routinely used to nondestructively map the surface-ultrastructure of soft biological samples under physiological conditions with unprecedented lateral resolution. Owing to its force detection sensitivity that ranges from nano-Newtons down to a few pico-Newtons, the AFM has become an established technique for exploring kinetic and structural details of inter- and intramolecular interactions and biomolecular recognition processes. The combination of such single-molecule force measurements with topographical imaging has led to the development of recognition imaging, which allows for identification and mapping of specific components in complex biological samples with high spatial accuracy. In the following, the basic principles of biologically relevant AFM imaging modes, as well as the methods of single-molecule force spectroscopy (SMFSsingle-moleculeforce spectroscopy (SMFS)) and simultaneous topography and recognition imaging (TREC) will be introduced and discussed. Selected experiments will be presented in more detail to illustrate the combined application of these techniques in the elucidation of questions in molecular biology, pharmaceutical science and the medical field.

Constanze Lamprecht, Jürgen Strasser, Melanie Koehler, Sandra Posch, Yoojin Oh, Rong Zhu, Lilia A. Chtcheglova, Andreas Ebner, Peter Hinterdorfer

26. Superresolution Microscopy

There are many types of optical microscopy systems that produce superresolution. This discussion centers on optical microscopy techniques that have the potential to extract features from objects that are one the scale of 100 nm or less, which is much smaller than what can be achieved with a classical optical microscope.In order to achieve resolution on the order of 100 nm with visible-light photons, more information must be obtained from the system than a single image using classical illumination can produce. In some cases, the extra information is in the form of a series of images with a customized illumination pattern. In other systems, the object displays response characteristics that effectively reduce the size of the scanning laser spot used to illuminate it. In yet other systems, light is forced through a nanosized aperture and then scanned over the object.None of the systems described in this chapter actually change the characteristics or physics of the optical systems used to collect photons. Instead, classical optical systems are cleverly combined with advanced illumination techniques and postprocessing that produce superresolution images.In the introduction, basic concepts regarding classical resolution are reviewed, and terms are defined that are important with respect to understanding how superresolution microscopy works. Subsequent sections describe superresolution techniques, including scanning aperture techniques, 4-Pi microscopy, enhancement/depletion techniques, photoactivated localization, lattice light-sheet microscopy, and structured illumination. A short comparison of techniques for live-cell imaging is also provided. Although examples of the techniques are given, this chapter is not intended to be a state-of-the-art review inclusive of all variations. Instead, the intent is to provide a basic understanding of the primary classes of superresolution microscopy techniques.It is notable that work in this area has generated several recent Nobel prizes, because of the importance to science of being able to resolve structures and physiology at the nanoscale [26.1].

Tom D. Milster

Bio/Nanotribology and Bio/Nanomechanics

Frontmatter

27. Nanotribology, Nanomechanics and Materials Characterization

Nanotribology and nanomechanics studies are needed to develop a fundamental understanding of interfacial phenomena on a small scale, and to study interfacial phenomena in micro/nanoelectromechanical systems (MEMSmicroelectromechanical system (MEMS)/NEMSnanoelectromechanical system (NEMS)), magnetic storage devices, and many other applications. Friction and wear of lightly loaded micro/nanocomponents are highly dependent on surface interactions (a few atomic layers). These structures are generally coated with molecularly thin films. Nanotribology and nanomechanics studies are also valuable in the fundamental understanding of interfacial phenomena in macrostructures, and provide a bridge between science and engineering. An atomic force microscope (AFMatomic force microscopy (AFM)) tip is used to simulate a single-asperity contact with a solid or lubricated surface. AFMs are used to study the various tribological phenomena, which include surface roughness, adhesion, friction, scratching, wear, detection of material transfer, and boundary lubrication. In situ surface characterization of local deformation of materials and thin coatings can be carried out using a tensile stage inside an AFM. Mechanical properties such as hardness, Young's modulus of elasticity, and creep/relaxation behavior can be determined on micro- to picoscales using a depth-sensing indentation system in an AFM. Localized surface elasticity and viscoelastic mapping near surface regions can be obtained with nanoscale lateral resolution. Finally, an AFM can be used for nanofabrication/nanomachining.

Bharat Bhushan

28. Surface Forces and Nanorheology of Molecularly Thin Films

In this chapter, we describe the static and dynamic normal forces that occur between surfaces in vacuum or liquid and the different modes of friction that can be observed between:1.Bare surfaces in contact (dry or interfacial friction)2.Surfaces separated by a thin liquid film (lubricated friction)3.Surfaces coated with organic monolayers (boundary friction).Experimental methods suitable for measuring normal surface forces, and adhesion and friction (lateral or shear) forces of different magnitude at the molecular level are described. We explain the molecular origin of van der Waals, electrostatic, solvation and polymer-mediated interactions, and basic models for the contact mechanics of adhesive and nonadhesive elastically deforming bodies. The effects of interaction forces, molecular shape, surface structure and roughness on adhesion and friction are discussed.Simple models for the contributions of the adhesion force and external load to interfacial friction are illustrated with experimental data on both unlubricated and lubricated systems, as measured with the surface forces apparatus. We discuss rate-dependent adhesion (adhesion hysteresis) and how this is related to friction. Some examples of the transition from wearless friction to friction with wear are shown.Lubrication in different lubricant thickness regimes is described together with explanations of nanorheological concepts. The occurrence of and transitions between smooth and stick–slip sliding in various types of dry (unlubricated and solid boundary lubricated) and liquid lubricated systems are discussed based on recent experimental results and models for stick–slip involving memory distance and dilatancy.

Dong Woog Lee, Marina Ruths, Jacob N. Israelachvili

29. Atomic Scale Friction Phenomena

Frictionfriction has long been the subject of research: the empirical da Vinci–Amontons friction laws have been common knowledge for centuries. Macroscopic experiments performed by the school of Bowden and Tabor revealed that macroscopic friction can be related to the collective action of small asperities. Over the last 25 years, experiments performed with the atomic force microscope have provided new insights into the physics of single asperities sliding over surfaces. This development, together with the results from complementary experiments using surface force apparatus and the quartz microbalance, have led to the new field of nanotribology. At the same time, increasing computing power has permitted the simulation of processes that occur during sliding contact involving several hundreds of atoms. It has become clear that atomic processes cannot be neglected when interpreting nanotribology experiments. Even on well-defined surfaces, experiments have revealed that atomic structure is directly linked to friction force. This chapter will describe friction force microscopy (FFMfriction force microscopy (FFM)) experiments that reveal, more or less directly, atomic processes during sliding contact.We will begin by introducing friction force microscopy, including the calibration of cantilever force sensors and special aspects of the ultrahigh vacuum environment. The empirical Prandtl–Tomlinson modelTomlinson model often used to describe atomic stick–slip results is therefore presented in detail. We review experimental results regarding atomic friction, including thermal activation, velocity dependence, and temperature dependence. The geometry of the contact is crucial to the interpretation of experimental results, such as the calculation of the lateral contactlateralcontact stiffness stiffness. The onset of wear on the atomic scale has recently been studied experimentally and it is described here. The chapter ends with a discussion of recent experiments aimed at detecting the dissipative forces acting when a sharp tip is moved parallel and very close to a solid surface without being in contact with it, or when small entities such as single polymer chains, graphene nanoribbons, or large organic molecules are manipulated.

Enrico Gnecco, Rémy Pawlak, Marcin Kisiel, Thilo Glatzel, Ernst Meyer

30. Computer Simulations of Nanometer-Scale Indentation and Friction

Engines and other machines with moving parts are often limited in their design and operational lifetime by friction and wear. This limitation has motivated the study of fundamental tribological processes with the ultimate aim of controlling and minimizing their impact. The recent development of miniature apparatus, such as microelectromechanical system (MEMS)microelectromechanical systems (MEMSmicroelectromechanical system (MEMS)nanometer-scaledeviceatomic frictions) and nanometer-scale devices, has increased interest in atomic-scale friction, which has been found to, in some cases, be due to mechanisms that are distinct from the mechanisms that dominate in macroscale friction.Presented in this chapter is a review of computational studies of tribological processes at the atomic and nanometer nanometerscale. In particular, a review of the findings of computational studies of nanometer-scaleindentationnanometer-scale indentation, nanometer-scalefrictionfriction and lubrication nanometer-scalelubricationis presented, along with a review of the salient computational methods that are used in these studies, and the conditions under which they are best applied.

Susan B. Sinnott, Seong-Jun Heo, Donald W. Brenner, Judith A. Harrison, Douglas L. Irving

31. Cellular Nanomechanics

Numerousnanomechanicsapplications of nanotechnology have been developed to understand mechanobiology of living cells and probe their unique mechanical properties in health and disease. In addition, since biological materials exhibit such a wide spectrum of properties, they offer new concepts for nonbiological biomimetic applications. In this chapter, the biomechanical properties of a cell and its subcellular compartments are described. First, a qualitative picture is presented of the relevant building blocks: the cytoskeleton, cell membrane, nucleus, adhesive complexes, and motor proteins. Next, the various methods used to probe cellular and subcellular mechanics are described, and some of the quantitative results presented. These measurements are then discussed in the context of several theories and computational methods that have been proposed to help interpret the measurements and provide nanomechanical insight into their origin. Finally, current understanding is summarized in the context of directions for future research.

Roger D. Kamm, Jan Lammerding, Mohammad R. K. Mofrad

32. Nanomechanical Properties of Nanostructures and Scale Effects

Structural integrity is of paramount importance in all devices. Load applied during the use of devices can result in component failure. Cracks can develop and propagate under tensile stresses, leading to failure. Knowledge of the mechanical properties of nanostructures is necessary for the design of realistic micro/nanoelectromechanical systems (MEMSmicroelectromechanical system (MEMS)/NEMSnanoelectromechanical system (NEMS)) and biological micro/nanoelectromechanical systems (bioMEMS/bioNEMS) devices. Elastic and inelastic properties are needed to predict deformation from an applied load in the elastic and inelastic regimes respectively. The strength property is needed to predict the allowable operating limit. Some properties of interest are hardness, elastic modulus, bending strength, fracture toughness, and fatigue strength. Many of the mechanical properties are scale dependent. Therefore, these should be measured at relevant scales. Atomic force microscopy and nanoindenters can be used to evaluate the mechanical properties of micro/nanoscale structures.Commonly used materials in MEMS/NEMS are single-crystal silicon and silicon-based materials, e. g., SiO2 and polysilicon films deposited by low-pressure chemical vapor deposition. Single-crystal SiC deposited on large-area silicon substrates is used for high-temperature micro/nanosensors and actuators. Amorphous alloys can be formed on both metal and silicon substrates by sputtering and plating techniques, providing more flexibility in surface integration. Electroless deposited Ni-P amorphous thin films have been used to construct microdevicesmicrodevice, especially using the so-called Lithographie, Galvanoformung, Abformung (LIGAlithography, electroforming and molding (LIGA)lithography, electroforming and molding (LIGA)technique) techniques. Micro/nanodevices need conductors to provide power, as well as electrical/magnetic signals to make them functional. Electroplated gold films have found wide application in electronic devices because of their ability to make thin films and because they process simply. Polymers, such as poly(methyl methacrylate) (PMMApoly(methyl methacrylate) (PMMA)), poly(dimethylsiloxane) (PDMSpoly(dimethylsiloxane) (PDMS)nanofluidicdevicepolymerbiocompatiblebiomedicaldevice), and polystyrene are commonly used in BioMEMS/BioNEMS such as micro/nanofluidic devices because of the ease of manufacturing and reduced cost. Many polymers are biocompatible, so they may be integrated into biomedical devices.This chapter presents a review of mechanical property measurements on the micro/nanoscale of various materials of interest and stress and deformation analyses of nanostructuresnanostructurestress and deformation analysis.

Bharat Bhushan

Molecularly-Thick Films for Lubrication

Frontmatter

33. Nanotribology of Ultrathin and Hard Amorphous Carbon Films

One of the best materials to use in applications that require very low wear and reduced friction is diamond, especially in the form of a diamond coating. Unfortunately, true diamond coatings can be deposited only at high temperatures and on selected substrates, and they require surface finishing. However, the mechanical, thermal, and optical properties of hard, amorphous carbon – commonly known as a diamond-like carbon (DLCdiamond-like carbon (DLC)) coating – can be tailored to be similar to those of diamond. It can also be deposited at a wide range of thicknesses using a variety of deposition processes on various substrates at or near room temperature. The coatings reproduce the topography of the substrate, removing the need for surface finishing. Various physical and chemical characterization techniques have been used to study the structure, stoichiometry, and mechanical and tribological properties. The friction and wear properties of some DLC coatings make them very attractive for some tribological applications. The most significant current industrial applications of DLC coatings are in magnetic storage devices, micro/nanoelectromechanical systems, and various other consumer products including razor blades, sunglasses, and optical windows.In this chapter, the state-of-the-art in the chemical, mechanical, and tribological characterization of ultrathin amorphous carbon coatings as thin as 5 nm is presented.

Bharat Bhushan

34. Self-Assembled Monolayers for Nanotribology and Surface Protection

In many applications, hydrophobic and lubricating films are needed to minimize adhesion, stiction, friction, and wear. In various applications, surfaces need to be protected from exposure to the operating environment, and hydrophobic films are of interest. Self-assembled monolayers are molecularly thick, well organized, and chemically bonded to the substrate. Some can be insensitive to the environment and can provide lower adhesion, friction, and wear. Ordered molecular assemblies with high hydrophobicity and desirable nanotribological properties can be engineered using chemical grafting of various polymer molecules with suitable functional head groups, spacer chains, and nonpolar surface terminal groups.In this chapter, we present an overview of self-assembled monolayers (SAMself-assembled monolayer (SAM)s) with hydrophobicity and desirable nanotribological properties. SAMs are produced by various organic precursors. We first present a primer to organic chemistry, followed by an overview of selected SAMs with various substrates, spacer chains, and terminal groups in the molecular chains, and an overview of nanotribological properties of SAMs. The contact angle, adhesion, friction, and wear properties of SAMs having various spacer chains with different surface terminal and head groups (hexadecane thiol, biphenyl thiol, perfluoroalkylsilane, alkylsilane, perfluoroalkylphosphonate, and alkylphosphonate) and on various substrates (Au, Si, and Al) are surveyed. Chemical degradation mechanisms and environmental effects are presented. Based on the contact angle and nanotribological properties of various SAM films discovered using an atomic force microscope (AFMatomic force microscopy (AFM)), it is found that perfluoroalkylsilane and perfluorophosphonate SAMs exhibit attractive hydrophobic and nanotribological properties.

Bharat Bhushan

35. Nanoscale Boundary Lubrication Studies

Boundary films are formed by physisorption, chemisorption, and chemical reaction. A good boundary lubricant should have a high degree of interaction between its molecules and the solid surface. As a general rule, liquids are good lubricants when they are polar and thus able to grip solid surfaces (or be adsorbed). In this chapter, we present an overview of various perfluoropolyethers (PFPEperfluoropolyether (PFPE)s) and ionic liquid films. PFPEs exhibit the highest chemical and thermal stability. Ionic liquid films possess efficient heat transfer properties and some electrical conductivity properties of interest. We present a summary of nanodeformation, molecular conformation, and lubricant spreading studies, followed by an overview of the nanotribological properties of polar and nonpolar PFPEs and ionic liquid films studied by atomic force microscopy (AFMatomic force microscopy (AFM)), and chemical degradation studies using a high vacuum tribotest apparatus.

Bharat Bhushan

Biomimetics and Bioinspired Surfaces

Frontmatter

36. Plant Surfaces: Structures and Functions for Biomimetic Applications

This chapter presents an overview of plant surface structuresplant surfacestructure and their evolution, combines surface chemistry and architecture with their functions and refers to possible biomimetic applicationsbiomimeticapplication.Within some 3.5 billion years biological species evolved highly complex multifunctional surfacesmultifunctional surface for interacting with their environments, providing some 10 million living prototypesliving prototype (i. e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structureshierarchicalstructure and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step in the invasion of terrestrial habitats some 350−450 million years ago by plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it many biological role modelsbiologicalrole model.Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing features. Superhydrophilicitysuperhydrophilicity and superhydrophobicitysuperhydrophobicity are focal points in this chapter. We estimate that superhydrophobic plant leaves (e. g., grasses) comprise in total an area of around 250 million km2, which is about 50% of the total surface of our planet.A survey of structures and functions based on our own examinations of almost 20000 species is provided; for further references we refer to [36.1]. A basic difference exists between aquatic nonvascular and land-living vascular plants; the latter exhibit a particularly intriguing surface chemistrysurfacechemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular waxepicuticular wax and the curvature of single cells up to complex multicellular structuresmulticellularstructure. A descriptive terminology for this diversity is provided.Simplified, the functions of plant surface characteristics may be grouped into six categories:1.Mechanical properties2.Influence on reflection and absorption of spectral radiation3.Reduction of water loss or increase of water uptake, moisture harvesting4.Adhesionadhesion and nonadhesion (lotus effectlotuseffect, insect trapping)5.Dragdrag and turbulence increase6.Air retention underwater for drag reductiondragreduction or gas exchange (Salvinia effectSalviniaeffect).This list is far from complete.A short overview of the history of bionicsbionics and the impressive spectrum of existing and anticipated biomimetic applications are provided. The major challenge for engineers and materials scientists, the durability of the fragile nanocoatings, is also discussed.

Wilhelm Barthlott, Matthias Mail, Bharat Bhushan, Kerstin Koch

37. Bioinspired Nanostructured Anti-Biofouling and Anti-inorganic Surfaces

In this chapter, biofouling and inorganic fouling areantibiofouling introduced. I then summarize fields susceptible to fouling followed by discussion of biofouling and inorganic fouling formation mechanisms, antifouling strategies from living nature, and current prevention and cleaning techniques. Finally, demonstrations of the antifouling uses of bioinspired rice leaf surfaces are presented. The data shows that micropatterned surfaces facilitate antifouling.

Bharat Bhushan

Micro/Nanodevice Reliability

Frontmatter

38. MEMS/NEMS and BioMEMS/BioNEMS: Tribology, Mechanics, Materials and Devices

A number of micro/nanoelectromechanical systems (MEMSmicroelectromechanical system (MEMS)/NEMSnanoelectromechanical system (NEMS)) and bioMEMS/bioNEMS are used in commercial applications and/or are under development. Surface area-to-volume ratio in MEMS/NEMS is large, and surface forces such as adhesion, friction, and meniscus and viscous forces become very large compared to inertial and electromagnetic forces. Some devices are designed to execute expected functions with short durations, typically in the millisecond to picosecond range. The expected life of the devices for high-speed contacts can vary from a few hundred thousand to many billions of cycles, e. g., over a hundred billion cycles for digital micromirror devices (DMDdigitalmicromirror device (DMD)s). This puts serious requirements on materials in systems involving relative motion. Thus, there is a need for a fundamental understanding of adhesion, friction/stiction, wear, lubrication, and the role of surface contamination and environment, all on the nanoscale. Most mechanical properties are known to be scale dependent. Therefore, the properties of nanoscale structures need to be measured. For bioMEMS/bioNEMS, adhesion between biological molecular layers and the substrate, and friction and wear of biological layers can be important. Component-level studies are required to provide a better understanding of the tribological phenomena occurring in MEMS/NEMS. This chapter presents an overview of nanoscale adhesion, friction, and wear studies of materials and lubrication for MEMS/NEMS and bioMEMS/bioNEMS, and component-level studies of stiction phenomena in MEMS/NEMS devices.

Bharat Bhushan

39. Friction and Wear in Micro- and Nanomachines

The prediction and characterization of multilength-scale tribological phenomena is challenging, yet essential for the advancement of micro- and nanomachine technology. Here, we consider theoretical underpinnings of multiasperity friction, review various approaches to measure micro- and nanoscale friction and discuss the effect of monolayer coatings to reduce friction and wear. We then overview a theoretical framework known as rate-and-state friction (RSFrate-and-state friction (RSF)), in which friction is considered to be a continuous function of velocity and interface state. A microscale test platform that is used to measure friction over multiple decades of velocity and normal load is presented and results are reported. Using the RSF framework, we quantitatively predict and validate the transition from stick-slip to steady sliding, enabling the creation of a microscale kinetic phase diagram. Next, we take a brief look at continued progress in spinning micromachine motor technology. Finally, we discuss wear- and tribopolymer-related phenomena in micro- and nanoswitches, which are promising devices to complement transistors due to their low on resistance and steep subthreshold swing. We anticipate great progress towards reliable, contacting micro- and nanomachines by linking theory and experiment to nano- and microscale tribological phenomena and by improving the testing, materials and processing methods used to characterize these phenomena.

Maarten P. de Boer, Sameer S. Shroff, Frank W. DelRio, W. Robert Ashurst

40. Failure Mechanisms in MEMS/NEMS Devices

The commercialization of MEMS/NEMS devices is proceeding slower than expected, because the reliability problems of microscopic components differ from macroscopically known behavior. In this chapter, we provide an overview of the state of the art in MEMS/NEMS reliability. We discuss the specific, MEMS-related problems caused by stiction due to surface forces and electric charge. Materials issues such as creep and fatigue are treated as well. Nanoscale wear is covered briefly. MEMS packaging is also discussed, because the reliability of MEMS/NEMS components critically depends on the available protection from the environment.

W. Merlijn van Spengen, Robert Modliński, Robert Puers, Anne Jourdain

41. Mechanical Properties of Micromachined Structures

To be able to accurately design structures and make reliability predictions, it is first necessary to know the mechanical properties of the materials that make up the structural components. In the fields of microelectromechanical systems (MEMSmicroelectromechanical system (MEMS)) and nanoelectromechanical systems (NEMSnanoelectromechanical system (NEMS)residual stressstressresidualYoung's moduluspolysilicon (poly-Si)), the devices are necessarily very small. The processing techniques and microstructures of the materials in these devices may differ significantly from bulk structures. Also, the surface area to volume ratio in these structures is much higher than in bulk samples, and so the surface properties become much more important. In short, it cannot be assumed that mechanical properties measured using bulk specimens will apply to the same materials when used in MEMS and NEMS. This chapter will review the techniques that have been used to determine the mechanical properties of micromachined structures, especially residual stress, strength, and Young's modulus. The experimental measurements that have been performed will then be summarized, in particular the values obtained for polycrystalline silicon (polysilicon).

Harold Kahn

42. High Volume Manufacturing and Field Stability of MEMS Products

Low-volume microelectromechanical systems (MEMSmicroelectromechanical system (MEMS))/nanoelectromechanical systems (NEMSnanoelectromechanical system (NEMS)) production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high-volume production adds requirements on design, process control, quality, product stability, market size, market maturity, internal capacity, and capital investment or transfer to foundry and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers and gyroscopes that are in high-volume production. What is described here also applies to other MEMS products such as pressure sensors, image projection systems, microphones, etc. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard well-controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. When transferring to an external foundry, existing processes are modified to utilize the foundry equipment and processes where possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products, partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high-volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost – a result that is normally achieved only after a product is in high-volume production. During the early years, IC companies reduce cost and financial risk by using existing facilities for low-volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are significant factors in MEMS product cost. MEMS devices have extremely high surface-to-volume ratio, so performance and stability may depend on the control of surface characteristics after packaging. Looking into the future, the competitive advantage of IC suppliers is decreasing because MEMS foundries are growing and small companies are learning to integrate MEMS/NEMS devices with die from CMOS foundries in one package. Packaging challenges still remain, because most MEMS/NEMS products must interact with the environment without degrading stability or reliability.

T. Kieran Nunan, Mark G. da Silva

43. Packaging and Reliability Issues in Micro/Nano Systems

The potential of microelectromechanical systems (MEMSmicroelectromechanical system (MEMS))/nanoelectromechanical systems (NEMSnanoelectromechanical system (NEMS)) technologies has been viewed as a revolution comparable to or even greater than that of microelectronics. The scientific and engineering advancements in MEMS/NEMS could enable applications that were previously unthinkable, from space systems, environmental instruments, to appliances for use in daily life. As presented in previous chapters, development of core MEMS/NEMS processes has already demonstrated many commercial applications as well as potential for advanced functionality in the future. However, low-cost and reliable packaging for protection of these MEMS/NEMS products remains a very difficult challenge. Without addressing these packaging and reliability issues, no commercial products can be sold on the market. Packaging design and modeling, packaging material selection, packaging process integration, and packaging cost are the main issues to be considered when developing a new MEMS packaging process. In this chapter, we present the fundamentals of MEMS/NEMS packaging technology, including packaging processes, hermetic and vacuum encapsulation, wafer-level packaging, three-dimensional (3-Dthree-dimensional (3-D)) packaging, polymer-MEMS assembly and encapsulation, thermal issues, packaging reliability, and future packaging trends. Specifically, development of MEMS packaging will rely on successful implementation of several unique techniques, including packaging design kits for system and circuit designers, low-cost and high-yield wafer-level, chip-scale packaging techniques, effective testing techniques at wafer level to reduce overall testing costs, and reliable fabrication of an interposer [43.1] with vertical through interconnects for device integration.

Yu-Chuan Su, Jongbaeg Kim, Yu-Ting Cheng, Mu Chiao, Liwei Lin

Nanotechnology and Society and Education

Frontmatter

44. Nanotechnologies in Societal Context

This chapter provides an overview of the past decade of research on the societalsocietal aspects and implications of nanotechnology in the USA. It starts by providing key terms and definitions and then outlines the contours of the social, ethical, governance, and participatory research in the USA, with key examples of nanoELSInanoELSI work. The chapter argues that all these elements are different facets of responsible development and responsible innovation, and that the National Nanotechnology Initiative's investment in nanoELSI research, education and outreach has provided an unprecedented advance in scholarship and policy. The chapter proposes that nanoELSI has in some respects developed new forms of hybrid social science, ethics, historical, legal, sociological, psychological interdisciplinarity in addition to the interdisciplinary collaborations that form the basis of much nanoscale science and engineering innovation. Integration of the societal and the technical is an ongoing challenge, and the chapter cites some notable advances in this area as well.

Barbara Herr Harthorn

45. Environment, Health and Safety Issues in Nanotechnology

With the rapid development of nanotechnology and its application, lots of nanomaterials or nanorelated products are now used in society. Nanotechnology offers substantial economic and societal benefits, but its impacts on environment, health, and safety (EHS) issues are not clearly understood or defined. Interactions between nanomaterials (sourced from nanotechnology development) and the human body and even with the ecological system have attracted much concern. In this chapter, the impacts of the development of nanotechnology on EHS issues has been surveyed focusing on present knowledge of the most important nanomaterials, dominant physicochemical characteristics which contribute to relevant toxicities, and state-of-the-art techniques and established biomarkers within this research field. This information may not be enough to fill the knowledge gap concerning the impacts of nanotechnology on EHS, but should help scientists and authorities to realize the risks involved and to take steps for sustainable development in the foreseeable future.

Rui Chen, Chunying Chen

46. Nanoscience and Nanotechnology Convergence

A series of major conferences that emerged from the National Nanotechnology Initiative explored connections to other fields of science and engineering, resulting after 15 years in a comprehensive vision of how science, technology, and society could converge. One of two initial orientations focused on the human and ethical implications of nanotechnology, thus connecting nanoscience to the social sciences. The other considered the current partnership and possible future unification of four NBIC domains: Nanotechnology, Biotechnology, Information technology, and new technologies based in Cognitive science. Most recently, the extensive series of book-length conference reports has led to a comprehensive overview, Handbook of Science and Technology Convergence, that outlines concepts, research methods, and educational approaches across four platforms that comprehensively define the world in which humans live:1.Foundational technologies2.Human-scale phenomena3.The Earth-scale system4.Societal-scale implications.

William S. Bainbridge

47. Global Perspectives of Nanotechnology Education

The continued advancement of research and applications described in this book depends on the quality of the next generation of scientists and engineers who will lead the nanoetchnology revolution. This chapter first reviews the growth of nanotechnology education then describes the successful efforts of educators on six continents in developing the nanotechnology talents of their students. Examples of educational programs at the primary, secondary, undergraduate, and graduate levels, for teacher training, vocational education training, and for informal education of the general public are each presented.

Kurt Winkelmann, Bharat Bhushan

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