Nanostructured Crystals
In this section we discuss the properties of crystals made of ordered arrays of nanoparticles. There are some instances of what might be called natural nanocrystals. An example is the 12-atom boron cluster, which has an icosahedral structure, that is, one with 20 faces. There are a number of crystalline phases of solid boron containing the B 2 cluster as a subunit. One such phase with tetragonal symmetry has 50 boron atoms in the unit cell, comprising four B12 icosahedra bonded to each other by...
The Importance of Nanoscale
The Greek word nano (meaning dwarf) refers to a reduction of size, or time, by 10-9, which is one thousand times smaller than a micron. One nanometer (nm) is one billionth of a meter and it is also equivalent to ten Angstroms. As such a nanometer is 10-9 meter and it is 10,000 times smaller than the diameter of a human hair. A human hair diameter is about 50 micron (i.e., 50x 10-6 meter) in size, meaning that a 50 nanometer object is about 1 1000th of the thickness of a hair. One cubic...
Nanometers Micrometers Millimeters
A nanometer, 10 9m, is about ten times the size of the smallest atoms, such as hydrogen and carbon, while a micron is barely larger than the wavelength of visible light, thus invisible to the human eye. A millimeter, the size of a pinhead, is roughly the smallest size available in present day machines. The range of scales from millimeters to nanometers is one million, which is also about the range of scales in present day mechanical technology, from the largest skyscrapers to the smallest...
Nanodiamond Applications
Being extremely small and with high amount of surface atoms, nanodiamond has diversified applications. Some applications involve using the superhard properties of diamond. The others may adapt low frictional coefficient of diamond (Table 7.1). 7.1 LUBRICATION OF ENGINE OIL AND MACHINE GREASE Nanodiamond can reduce significantly the frictional coefficient by coating on the sliding surface. The nanodiamond coating reduces the contact area. Moreover, the inertness of the diamond surface reduces...
Wetetched Silicon Structures
Microsystems technology relies on anisotropic wet etching of silicon for many major applications. Bulk micromechanics depends on silicon crystal plane-dependent etching, and many surface micromechanical and SOI devices make use of silicon wet etching for auxiliary structures, even though main device features are defined by plasma etching. Because < 100> silicon is the workhorse of microsystems, the discussion concentrates on it. Both < 110> and < 111 > etching will be reviewed...
Silicon Wafer Dry Etching Notching Effect Benefit -prevent -prevention
Where, the tensors Eijkl and Sjkl are replaced by Em,n and Sm,n, respectively. This can be obtained by substituting the indices ij m and kl n. In a cubic structure it can be considered that x, y and z directions are replaced by 11, 22, 33 and the corresponding planes xy 12 and 21, xz 13 and 31, yz 23 and 32 are in symmetry. With this representation the stress and strain components can be represented as x E11 x + E12 y + E13 z + E14 xy + E15 xz + E16 yz Sx S11CTx + S12ay + S13 z + S14rxy +...
Float zone FZ crystal growth
If high purity or oxygen-free silicon is needed, float zone (FZ) crystal growth is used. In the FZ-method, a polysilicon ingot is placed on top of a single-crystal seed. The polycrystalline ingot is heated externally by an RF coil, which locally melts the ingot. The coil and the melted zone move upwards, and a single crystal solidifies on top of the seed crystal. The highest FZ-silicon resistivities are of the order of 20 000 ohm-cm, compared to 100 to 1000 ohm-cm for CZ. Because there is no...
Using Wet Etch and Wafer Bonding
The use of anisotropic wet etchants to remove silicon can be regarded as the beginning of the micromachining era. Back side etch was used to create movable structures such as beams, membranes, and plates, Fig. 5.20. Initially, the etching was timed to create a specified thickness. However, this technique proved inadequate in creating thin structures (< 20 m). Subsequent use of various etch stop techniques allowed the creation of thinner membranes in a more controlled fashion. As mentioned in...
Etching and Substrate Removal
Thin film and bulk substrate etching is another fabrication step that is of fundamental importance to both VLSI processes and micro nanofabrication. In the VLSI area, various conducting and dielectric thin films deposited for passivation or masking purposes must be removed at some point or another. In micro nanofabrication, in addition to thin film etching, very often the substrate silicon, glass, GaAs, etc. also needs to be removed in order to create various mechanical micro- nanostructures...
Characterising Etching Processes in Bulk Micromachining
Department of Electronics and Communication Engineering, Vellore Institute of Technology, Tamilnadu, India Machining is defined as a process of removing material from a workpiece in the form of chips in order to obtain exact shapes and sizes. It is a well-defined process method in machine design and tooling . It includes several methods, which are usually divided into three main classes such as cutting, abrasive processes, and nontraditional machining. Machining processes design and manufacture...
Ion Beam Etching
(1) diode reactors with horizontal target plates for single-wafer processing, (2) triodes with an extra electrode used for increased ion bombardment, and (3) hexodes designed for batch processing in which the vertically arranged cathode has the shape of a hexagon surrounded by the cylindrical chamber walls forming the anode. A disadvantage of the contact plasma reactors is that the flux of all the impinging species at the sample surface is difficult to control. A way to improve this is by way...
Structuring Metal Films
There are many good reasons to microstructure metal films thin metal foils with holes can be used as membranes (Figure 8.9(a)) for separating small particles, disjoint metal Figure 8.9 Etching micropatterns into metals. (a) Array of circular holes etched through a freestanding, 100 mm thick copper foil the holes correspond to disjoint, raised features in the gel stamp. (b) Disjoint metal plates obtained from the same foil the lines along which the foil is 'cut' correspond to the network of...
Electron Beam Resists
EBL is classified as a reactive processing in terms of Electron Beam Processing. In this process, ionization and excitation of constituent molecules of the material occur during the scattering of the incident electrons. Some excited molecules lose their energy by collisions with other molecules and change into radicals. All these ions, excited molecules, radicals, and the secondary electrons are called active species that induce chemical reactions inside the material. Electron beam resists are...
Arc Discharge Production of MWNTs
3.2.1 General Technical Features of the Production Process The carbon arc technique for generating MWNTs appears very simple, but obtaining high yields of tubes is difficult and requires careful control of experimental conditions. In the most common laboratory scale production scheme, the direct current (DC) arc operates in a 1- to 4-mm wide gap between two graphite electrodes 6 to 12 mm in diameter that are vertically or horizontally installed in a water-cooled chamber filled with helium gas...
Introduction To Bridging Ligands
Bridging ligands have received much interest recently due to their ability to couple metal centers in a covalent manner resulting in polymetallic complexes that often possess new and interesting properties. Bridging ligands of the type discussed herein bind to each metal through one or more donor atoms forming a coordinate covalent c-bond.
Variant 1 Classical styrene synthesis using an iron oxide catalyst
Styrene is synthesized in an industrial process that has been known for roughly 60 years the dehydrogenation of ethylbenzene. The dehydrogena-tion of ethylbenzene to produce styrene is a reversible endothermic balance reaction (Lieb & Hildebrand 1982) C6H5C2H5 C6H5C2H3 + H2 AH600 c 124.9 kJ mol (1) The dehydrogenation of ethylbenzene to produce styrene takes place at temperatures of 600 C in an ethylbenzene-water mixture and is assisted by potassium-promoted iron oxide catalysts. Along with...
In New Jersey, Solar Panels Beat the Stock Market with 324% Return on Investment
Say you live in New Jersey and have 25,500 to invest today. Where is the best place to put it for the next 15 years Stocks Bonds Try solar panels on your roof.Let's face it for many people, buying solar panels for the home is a serious investment. Here at 1BOG we knew that solar was a good investment in New Jersey, but we wanted provide our members with a better analysis of the long-term ROI (Return On Investment). Right now, an investment of 25,500 in a 7.
Zeta Potential For Gold Au
Iff7 106 105 104 103 102 101 Concentration of electrolyte equivalents per liter Fig. 3 Zeta potential profile of a positively charged alumina surface in the presence of various ions. Source From Ref. 3 . covalent bonding with surface atoms or be more physical, e.g., van der Walls forces between the ion and the surface or between the hydrocarbon chains of surfactant ions adsorbed. 3 Isoelectric Point and or Point of Zero Charge Although the isoelectric point iep and the point of zero charge pzc...
Bulk Micromachining
Bulk micromachining is one of the earliest processes in the field of microsystem technology 187-276 . While there are many different types of bulk micromachining, the basic concept is to create features out of a substrate. In general, a silicon, SOI, or glass wafer serves as the substrate material and the structures are created by way of removing (etching) the parts of the wafer that are not wanted, leaving the desired structure behind. Typically, this is done through a sequence of...
Thin Film Deposition and Doping
Thin-film deposition and doping are used extensively in micro nanofabrication technologies. Most of the fabri Fig. 5.2 Schematic drawing of the photolithographic steps with a positive photoresist (PR) cated micro nanostructures contain materials other than that of the substrate, which are obtained by various deposition techniques, or by modification of the substrate. The following is a list of a few typical applications for the deposited and or doped materials used in mi-cro nanofabrication...
Magnetic MEMS
The use of magnetic materials in MEMS is a recent development in which particular emphasis is given on ferromagnetic materials. These magnetic materials could be soft or hard. The design of ferromagnetic MEMS and the methods of integrating both soft and hard magnetic materials with it are a current research and development field. Soft ferromagnetic materials have found their usefulness in microsensors, microactuators, and microsystems. However, hard magnetic materials have unique advantages...
Conventional Micron Diamonds
Micron diamonds are indispensable for polishing industrial products including metals, ceramics, and plastics. There are several types of micron diamond fines. Most micron diamond fines are 4000 3000 2000 1500 1000 500 4000 3000 2000 1500 1000 500 Frequency cm ' Frequency cm1 Figure 5.10. The turning of hydrophilic diamond to hydrophobic by heating in hydrogen atmosphere (left). The conversion of hydrophilic diamond from hydrophobic one by heating in nitrogen atmosphere (right). Source Satoru...
Historical High Pressure Synthesis Of Diamond
Numerous methods using high pressure technology have been invented to synthesize diamond in the past. In fact, high pressure technology was developed largely because of the need to synthesize diamond. Hannay developed sealed steel tubes that could contain organic volatiles at high temperatures to about 0.2 GPa (1880). Parsons built a piston-cylinder apparatus that could bring pressures up to 1 GPa (1888). The Nobel laureate Moissan quenched molten steel to attain a pressure of about 0.5 GPa...
Near Field Scanning Optical Microscopy for Bioanalysis at Nanometer Resolution
Viallet, and Tuan Vo-Dinh The nondestructive imaging of biomolecules in nanometer domains in their original location and position as adsorbed or deposited on a surface is of garners considerable experimental interest. Near-field scanning optical microscopy (NSOM) is an emerging technique with its astonishing resolving power of X and greater than the aperture. Thus, subwavelength details of the image are lost. Over the past decade, NSOM has evolved into a new frontier...
Near Field Scanning Optical Microscopy
A TopoMetrix Aurora-2 NSOM was used for our experiments. A schematic of the NSOM system is shown in Figure 12.3. The fiber-optic probe (aperture size 60-100 nm) attached to a piezoelectric tuning fork was mounted on the removable Aurora-2 microscope head and positioned above the sample. A resonating frequency ranging between 90 and 100 kHz was selected with less than 1 nm lateral amplitude at the probe end.
Graphite and Related Materials Rdk
Graphite may be the thermodynamically most stable modification of carbon. Still it is chemically attacked more easily than diamond due to its layered structure and the comparatively weak interaction between the graphene sheets. Altogether the graphite's reactivity toward many chemicals is rather low nevertheless. With chlorine, for example, it does not react at all under usual conditions, and even with fluorine reaction occurs only at more than 400 C. Suitable performance yields the...
Characterising the Surface Micromachining Process
From the definition of the surface micromachining process, one can note that deposition of materials layers is used to create the desired structure of a typical device. Fig. 6.3 illustrates the surface micromachining process. (d) Pliotomasking Fig. 6.3 Surface micromachining process A silicon substrate is used as the ground plane. The first step in the surface micromachining process is the deposition of a thin isolation layer. This layer is deposited with a dielectric material such as silicon...
Superlattices
The concept of a superlattice The concept of the superlattice (SL) was proposed by Leo Esaki and coworkers in the late 60s and later fabricated by molecular beam epitaxy (MBE) techniques. Superlattices can be considered one of the most important man-made or artificial materials. A superlattice consists of a periodic set of MQW in which the thickness of the energy barriers separating the individual wells is made sufficiently small. As the barriers become thinner, the electron wave...
The Structure And Chemical Reactivity Of Carbon Nanotubes
As can be seen in Figures 6.1A amp B, carbon nanotubes may be viewed as a graphite sheet that is rolled up into a nanoscale tube form single-walled carbon nanotubes, SWCNTs FIGURE 6.1. Schematic representation of A single- multi-walled carbon nanotube formation by rolling up graphene sheet s . B carbon nanotube formation based on a 2D graphene sheet of lattice vectors a1 and a2, the roll-up chiral vector Ch na1 ma2, and the chiral angle 0 between Ch and a1. When the graphene sheet is rolled up...
Closed Multiporphyrin Arrays
H-bonds are directional and the cooperative formation of closed self-assembled arrays can result in sometimes surprisingly stable materials (Fig. 11). These relatively weak intermolecular interactions can be exploited in materials wherein responses to thermal or solvent polarity are desired. Other than temperature and solvent as factors in the assembly, the concentration range for the closed structures is limited. As is well known in biology, open polymeric structures are favored at high...
Amplitude Modulation Tapping Mode AFMs
In tapping mode, or AM-AFM, the cantilever is excited externally at a constant frequency close to its resonance. Oscillation amplitude and phase during approach of tip and sample serve as the experimental observation channels. Figure 15.6 shows a diagram of a typical tapping-mode AFM setup. The oscillation amplitude and the phase (not shown in diagram) detected with the photodiode are analyzed with a lock-in amplifier. The amplitude is compared to the set-point, and the difference or error...
Friction and Adhesion
To investigate the friction properties of Z-15 and Z-DOL(BW) films on Si(100), the friction force versus normal load curves were measured by making friction measurements at increasing normal loads 28.21 . The representative results ofSi(100),Z-15, and Z-DOL(BW) are shown in Fig. 28.6. An approximately linear response of all three samples is observed in the load range of 5-130 nN. The friction force of solid-like Z-DOL(BW) is consistently smaller than that for Si(100), but the friction force of...
Strain Effects in Nanostructures Due to Lattice Mismatch in Multi Quantum Wells
In the MBE growth of layered systems the lattice mismatch between barrier and well induces biaxial strains in the interface regions. These strains cause shifts of the LO phonon wavenumber, which are proportional to the strain. For compressive (tensile) strain a blueshift (redshift) of the phonon wavenumber can be observed 43, 115, 137-139 . The amount of this shift may depend on the layer thickness 39, 140, 141 . For ZnSe on GaAs, from the beginning of the epilayer growth large elastic strains...
Composition
Detailed knowledge of composition and its distribution within and around QDs is important for a thorough understanding of the QD growth mechanism and of the structure-property relationship of QDs. However, the determination of quantitative composition profiles of QDs is a very challenging task because of the small size of the QDs. As a result, the composition of QDs has been less investigated compared to their shape and size. Most investigations of QD composition suggest that the average...
Band Structure and Density of States of Carbon Nanotubes
It is essential to give a correct and conclusive description of the electronic properties of carbon nanotubes to get an understanding of their broad potential for applications. Chemists and physicists have developed two fundamentally different concepts of the matter. They are either based on considering electrons in molecular orbitals, especially in frontier orbitals, and on examining the n-system, or they pursue a solid-state physical approach that employs density-of-state functions and the...
SBA2 P63mmc Fm3m
SBA-2 was first synthesized by Stucky's group in 1995 by using Gemini surfactant C H2 +1N+(CH3)2(CH2)sN+ (CH3)3 (Cn_s_i) 10 . Based on powder XRD results, the material was believed to consist of discrete supercages in a hexagonal close-packed (hcp) arrangement and the space group was determined to be P63 mmc. The unit cell dimensions are a 6 nm and c 10 nm which can be tuned by changing Figure 5. TEM image of 3D porous single crystal of Cr2O3 synthesized using SBA-15 as a template which has...
Crystallography of Titanate Nanotubes
In an early study, Kasuga et al.1 characterized their product as anatase. In a recent paper, the crystal structure of nanotubular titanates was still been RSC Nanoscience amp Nanotechnology No. 12 Titanate and Titania Nanotubes Synthesis, Properties and Applications By Dmitry V. Bavykin and Frank C. Walsh Dmitry V. Bavykin and Frank C. Walsh 2010 Published by the Royal Society of Chemistry, www.rsc.org interpreted as anatase,2 despite the fact that the crystal structure of these nanotubes is...
Electron Diffraction Modes And Geometry
Electron optics in a microscope can be configured for different modes of illumination from a parallel beam to convergent beams. Figure 1 illustrates three modes of electron diffraction using different illuminations, 1) selected area electron diffraction (SAED), 2) nano-area electron diffraction (NED) and 3) convergent-beam electron diffraction (CBED). Variations from these three techniques include large-angle CBED 9 , convergent-beam imaging 10 , electron nanodiffraction 11 and their...
The Assemblies of NiC and NiO Particle Systems
Powder X-ray diffraction profiles of Fig. 1A clearly show the presence of a majority of fcc Ni, with a small amount of hexagonal Ni3C present from carbon-encapsulated Ni nanoparticles. Additionally, that the hexagonal Ni3C phase is detectable using XRD suggests that the hexagonal Ni3C most likely is one single phase along with majority of fcc Ni phase in these assemblies of Ni C nanoparticles. However, the main reflection peaks of XRD Fig. 1B for pure Ni nanoparticles coated with NiO layers are...
Periodic Phases 31 MCM41 P6mm
MCM-41 is the simplest and most extensively studied meso-porous silica 4 . In a typical example of synthesis, the alkyltrimethylammonium surfactants, C H2b+1-N(CH3)+X-(X Cl or Br, n 8-10, 12, 14, 16), one of so-called anionic surfactants described as S+I-, were used. According to the simplest picture of the LCT mechanism, these surfactant molecules form micellar rods (Fig. 1a), which further self-assemble into a hexagonal array (Fig. 1b). Silicate ions deposit on the surface of the micellar...
Melt Quenching Technique
The melt quenching technique is widely used to prepare glasses and glass-ceramics. It needs higher temperature compared to that required for the sol-gel technique, but it takes less time. The TiO2, BaTiO3, SrTiO3, doped vanadate glasses or the VP glasses or other low melting TMO glasses VP type base glasses , in general, can be prepared by a fast quenching method 48, 50 . For example, VP glass can be used to prepare a typical 80V205-20P205 xTiO2 type FGNC with different concentrations of TiO2 x...
Magnetic Micro Nano Bead Based Biochemical Detection System
In the past few years, a large number of microfluidic prototype devices and systems have been developed, specifically for biochemical warfare detection systems and portable diagnostic applications. The BioMEMS team at the University of Cincinnati has been working on the development of a remotely accessible generic microfluidic system for biochemical detection and biomedical analysis, based on the concepts of surface-mountable microfluidic motherboards, sandwich immunoassays, and electrochemical...
Optical Printing
Optical lithography comprises the formation of images with visible or near-UV radiation (A 300-380 nm) in a resist (e.g., Novolac) using shadow or projection printing. Shadow printing may be employed where the gap between mask and wafer is small. In case of projection printing, some sort of image-forming system (e.g., a 4 1 demagnification lens) is interposed between mask and wafer. The linewidth limit of optical printing lies near 0.4 m, although 0.2 m features may eventually be printed under...
Piezoelectric Actuation Mechanism
It is important to mention that the piezoelectric actuation is based on inverse piezoelectric effect, although the piezoelectric detection is based on direct piezoelectric effect. Note a piezoelectric material provides its own internal biasing requirement, either due to absence of a center of symmetry in the case of single-crystal materials such as aluminum nitride (AIN) or zinc oxide (ZnO) or due to a permanent polarization present in ferroelectric materials such lead-zirconate-titanate (PZT)....
Superconductors and the Superconducting Magnetic Flux Quantum
Superconductivity a Macroscopic Quantum State Superconductivity is less familiar (the effect requires a low temperature) and, perhaps, is more difficult to understand than ferromagnetism, the useful cooperative electron effect discussed earlier. In superconductors, each electron spin is paired with its opposite member across the Fermi surface. Each pair (k ,-kfl) has zero momentum p K and zero spin this pair is a Bose particle (like a photon, e.g. in a laser). An indefinitely large number of...
Bohrs Model of the Nuclear Atom
The structure of the atom is completely nanophysical, requiring quantum mechanics for its description. Bohr's semi-classical model of the atom was a giant step toward this understanding, and still provides much useful information. By in- Nanophysics and Nanotechnology An Introduction to Modern Concepts in Nanoscience. Second Edition. Edward L. Wolf Copyright 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN 3-527-40651-4 troducing, in 1913, a completely arbitrary quantum number, Bohr 1...
Energy Storage vs Energy Conversion Devices
Although each energy storage and conversion device is characterized by its particular structural and functional dissimilarities, they share common electrochemical foundations. In general terms, we can envisage these devices as electrode pairs in contact with a charge-carrier medium. The negative electrode is called the anode (oxidation reactions take place) where electrons are delivered to the external circuit. The positive electrode is called the cathode, where reduction reactions take place....
Subtractive and Additive Creation of Nanostructures
The predominant lithographic microtechnique is subtractive fabrication, which removes a deposited material from certain locations (cf. Section3.1). Subtractive principles can be transferred to nanotechnology. An analogous layer deposition can be used, but with reduced thicknesses. However, methods with a high lateral resolution and a high precision with respect to positioning are required for fabrication. These requirements exclude standard optical projection methods as applied in...
Crystal Structure of TiO2
TiO2 exists as three polymorphs, brookite, anatase and rutile. Among these, rutile is the most stable phase. Both the anatase and rutile structures are commonly used in photocatalysis applications. Figure 10.1 illustrates the crystal structures of TiO2 in the form of TiO6 octahedrons. Each octahedron can be considered as one Ti4 cation surrounded by six O2 anions. In rutile, each distorted octahedron is in contact with ten neighbor octahedrons two sharing edge oxygen pairs and eight sharing...
Flatband Potential and Donor Density
Flatband potential is an important parameter in deciding the performance of a semiconductor electrolyte junction towards hydrogen generation. The higher the flatband potential, the greater is the ability of the photoelectrode to split water. The most frequently used method for determination of the flatband potential at a semiconductor electrolyte interface is by Mott Schottky plots. If C is the junction capacitance at electrode potential Vapp, the Mott Schottky equation is given by where eo is...
Degenerate Semiconductors
In Section 3.4 we gave the name non-degenerate semiconductors to those for which the Fermi level EF is located in the gap at an energy of about 3kT or more away from the band edges. Since for these semiconductors, classical statistics could be applied, we derived simple expressions, Eqs (3.12) and (3.15), for the concentration of electrons and holes, respectively. Under these premises we also derived Eqs (3.24), (3.25), and (3.26) which give the location of the Fermi level for n-type, p-type,...
Excitonic Effects In Quantum Wells
In the case of confined systems for electrons and holes, such as quantum wells, wires, and dots, the excitonic effects are much more important than in bulk solids. In effect, the binding energy of the electron-hole system forming an exciton is much higher in quantum confined systems than in the case of solids, and, therefore, the excitonic transitions can be observed even at temperatures close to room temperature, as opposed to the bulk case for which low temperatures are needed. This makes the...
Living Water and Hydrophobic Interactions
Biomolecules have evolved and flourished in aqueous environments, and basic interactions among biomolecules and their pervasive hosts, water molecules, are extremely important. The properties of intracellular water are controversial. Many authors believe that more than 90 percent of intracellular water is in the bulk phase-water as it exists in the oceans (Cooke and Kuntz, 1974 Schwan and Foster, 1977 Fung and McGaughy, 1979). This traditional view is challenged by others who feel that none of...
MEMS Technology for Satellite Communications and Space Systems Applications
Wireless satellite communications and space-based sensors are the major beneficiaries of the MEMS technology. Minimum size, power consumption, and high reliability are the critical requirements for both the applications, which can be satisfied by deploying MEMS-based devices and sensors. MEMS technology conserves energy and minimizes power consumption, weight, and size. RF-MEMS devices such as switches, phase shifters, switched antennas, filters, and amplifiers have become critical to...
Where to Buy Ferrofluids
The science department or the science teacher can order sealed display cells of ferrofluids from Educational Innovations, Inc., at http www.teachersource.com (click on Browse or Search the Catalog , Electricity Magnetism Engines and then Ferrofluids ). A Ferrofluid Experiment Booklet is also available (item FF-150) for about 6. References .HTM READING MATERIAL Karn, Barbara, VickiColvin, Paul Alivasatos, Tina Masciangioli (Eds.). Nanotechnology and the Environment.
The Industrial Structure Giving Rise to Nanotechnology
We don't make the products you use, we make the products you use better. The phrase is a familiar one. We don't make the products you use, we make the products you use better. Although used in commercials by BASF, a company that adds value to existing products with its chemicals and plastics, this phrase could also be used to describe nanotechnology companies. Nanotechnology will serve to improve a number of different types of products in different industries. As we saw in Chapter 1,...
Venture Investment in Nanotechnology
Many nanotech start-ups are not yet ready for venture capital investment. First, despite the enormous resources being dedicated to exploring and engineering at the nanoscale, the field is still in its infancy. Many start-up companies have just recently spun out of breakthroughs in universities and cannot reasonably expect to develop commercial products for at least seven to ten years. Even nanotech companies that can demonstrate functional products lack the ability to scale up for mass...
Tensile stress positive a
Figure 7.12 Thin-film stresses a film that must be elongated to fit a wafer is under tensile stress (positive) and a film that is compressed to fit a wafer, is under compressive (negative) stress Stresses in thin films cause wafer curvature, as shown in Figure 7.12. Imagine a free film attached to a massive wafer and forcefit to the wafer size. Next, imagine, stress relaxation through the wafer curvature. A film under tensile stress will result in a concave shape, while a compressively stressed...
Applications of CNT Emitters
The range of potential applications for CNT-based field emission is very large. Any system that uses an electron source could potentially host a CNT field emission device. CNT field emitters are particularly suited when high efficiency is necessary, such as for most space and portable applications, when fast switching or ultrahigh frequency modulation are required and also, when very high current densities are desirable. Several applications for CNT emitters are discussed below. Vacuum...
Semiconductor Lithography
Electron beam lithography (EBL) is a specialized technique 57, 58 for creating the extremely fine patterns required by the modern electronics industry for integrated circuits. Derived from the early scanning electron microscopes, the technique in brief consists of scanning a beam of electrons across a surface covered with a resist film sensitive to those electrons, thus depositing energy in the desired pattern in the resist film. The process of forming the beam of electrons and scanning it...
Variant 1 the cathoderay tube CRT
The cathode-ray tube is the oldest and best known facility for generating moving images. A CRT monitor consists of a vacuum-filled (10-6 to 10-7 torr) glass bulb plus a heated cathode (voltage about 25 kV), also known as the hot cathode or electron gun (Abrams et al. 2003). When heated, the electrons of the negatively charged cathode begin to oscillate and are then emitted from it. Between the cathode and the anode exists an accelerating potential of several kV. Due to this voltage difference,...
DUV and VacuumUV Lithography
Serial processes are time-consuming and therefore not applicable for a cost-efficient and highly productive fabrication of devices with small structures. Therefore, large complexes of structures are transferred together in the size of a chip or larger areas. Such group transfer processes require a high optical precision and highly homogeneous illumination. Again, the wavelength limits the resolution. So a process of continuous stepwise improvement of equipment and technologies ranging from...
Classification and Structure of Doped Fullerenes
Fullerene solids are unique insofar as they can be doped in several different ways, including endohedral doping (where the dopant is inside the fullerene shell), substitutional doping (where the dopant is included in the fullerene shell), and the most commonly practiced exohedral doping (where the dopant is outside or between fullerene shells). Doped fullerenes in the crystalline phase are often called fullerides, in contrast to the term fullerite, which refers to the crystalline phase prior to...
NFMM Characterization of Magnetic Domains
We demonstrate the measurement of electromagnetic properties of magnetic layers in a HD platter by using a NSMM. As the magnetization changed, the intensity of the reflection coefficient Sn varied. The electromagnetic properties of a hard disk were estimated by measuring the microwave reflection coefficient Sn. Figure 5.25A shows the estimated microwave reflection coefficient dependence on the magnetic relative permeability of the CoCrPtTa soft magnetic layer of the HD plater. The inset shows a...
Biosensing of Fluids by a NFMM
The real-time detection and quantification of concentration of glucose, NaCl and other compounds in fluids with high sensitivity, selectivity, and accuracy is required in many different areas. Accurate and rapid measurement of the glucose concentration is very important in biological analysis and clinical monitoring and in the food processing industry 73-76 . Aqueous NaCl solutions play a fundamental role in many chemical processes in a variety of chemical and biological systems 77,78 . Here,...
Finite Element Model
Another, perhaps more natural observable in NFMM experiments, is the reflection coefficient Su as a function of frequency from which, of course, the frequency shift can be obtained or Sn as a function of material property for a fixed frequency 20,21 . However, to model Sn is not very straightforward in that one cannot work solely with electrostatics. Furthermore, there are distance scales of very different sizes, for example, the cavity of order centimeters and the tip-sample distance of order...
Nearfield Interaction
An important strategy for understanding natural and artificial materials is to study the interaction of the material with electromagnetic fields. The properties of metals, semiconductors, and dielectrics at low frequency have been a fruitful area of investigation. The first experiments were transmission experiments done in the far-field region from source, and typically required that the sample size be of the scale of the wavelength 22-26 . In the second generation some experiments were carried...
Vibrational Modes
In this chapter we review the lattice mode structure for the isolated fullerene molecules and for the corresponding molecular solid. Explicit results are given for C60, C70, and higher fullerenes. The effects of doping, photopolymerization, and pressure on the vibrational spectra are reviewed. 11.1. Overview of Mode Classifications Because solid C60 is very nearly an ideal molecular solid, its vibrational modes can be subdivided naturally into two classes intermolecular vibrations (or lattice...
Four Generations of Nano Product Development
In the case of the incorporation of nanomaterials into products, several generations of changes to manufacturing can be anticipated . Current products in the marketplace today typically fall into the 1st generation, where relatively minor modifications to existing processing equipment were needed to incorporate nanomaterials into the product For example, surface coatings of nanofibers and nanowhiskers have been used for improved filtration and for the nano-pants fabric made by Nano-Tex 3 . More...
Silica Based Porous Materials
A wide variety of different porous materials are known. Following the classification by IUPAC, they can be grouped by the size of their pores microporous solids with pore diameters up to 2 nm with zeolites and metal-organic frameworks (so-called MOF structures) as the most prominent representatives, mesoporous solids with pore sizes between 2 and 50 nm, e.g. aerogels, pillared clays, or M41S phases, and macroporous solids with pore sizes larger than 50 nm, such as foams or glasses. In addition,...
Physical Properties Of Micelles
Again, the common aspects of the self-assembly of surfactant (and amphiphilic polymer) systems are that it is a thermodynamic, random, and nonhierarchical process with molecular-length scale. This section provides details on this issue. The definitions of three important parameters for micelles also will be given critical micelle concentration (cmc), aggregation number (n), and degree of counterion binding on the surface of micelles (a) (Tanford, 1980 Zana, 1991 Nagarajan and Ruckenstein, 2000...
Atomic and Molecular Basis of Nanotechnology
The molecular theory of matter starts with quantum mechanics and statistical mechanics. According to the quantum mechanical Heisenberg Uncertainty Principle the position and momentum of an object cannot simultaneously and precisely be determined 8 . Then the first question that may come into mind is, how could one be able to brush aside the Heisenberg Uncertainty Principle, Figure 2, to work at the atomic and molecular level, atom by atom as is the basis of nanotechnology. The Heisenberg...
Fullerene Materials for Lithiumion Battery Applications
AMER Corporation, Tucson, Arizona 85706, USA Fullerene International Corporation, New York, NY 10022, USA Novel and high-performance anode materials based on modified fullerene materials, for lithium-ion rechargeable batteries were developed. The technical feasibility of lithium-ion intercalation and de-intercalation based on the degree of anion or atomic modification of the fullerene was examined. In this approach the fullerene molecule is viewed as a large anchor molecule to which various...
Coacervation Phase Separation
Coacervation-phase separation is a method to use a coacervation-inducing agent to reach the coacervation-phase separation during after the solvent evaporation to form the microcapsules or the nanocapsules. The coating can be controlled by changing the parameters during the process, so that the drug content, particle size distribution, biomedical properties, etc. of the microcapsules nanocapsules can be controlled. This procedure has been employed widely for preparation of microcapsules...
The Vibrating Uniform Lattice
The elastic, spring-like nature of the interatomic bonds, together with the massive atoms placed at regular intervals these are the items we isolate for a model of the classical mechanical dynamics of the crystal lattice see Box 2.3 for brief details on Lagrangian and Hamiltonian mechanics . Here we see that the regular lattice displays unique new features unseen elsewhere acoustic dispersion is complex and anisotropic, acoustic energy is quantized, and the quanta, called phonons, act like...
Absorption and Emission Spectroscopy of Carbon Nanotubes
Compared to the vibrational spectroscopy of carbon nanotubes, their absorption and luminescence spectroscopy kind of lives in the shadows. This is, however, not due to a lack of information these methods could provide to the understanding of the nanotubes' electronic structure. There are rather experimental complications that arise from the inhomogeneity of the available materials. These methods could especially elucidate the structure of bands farther distant from the Fermi level. Due to the...
Microtubule Organizing Centers MTOC and Centrioles
MTOC and their chief components, centrioles, are the specific apparatus within living cells which trigger and guide reorganization of cytoplasm such as occurs during growth, generation of form and function (differentiation) and cell movement. The enigmatic MTOC determine where, when, and how these functions occur (Figure 5.11). MTOC (or centrosomes) contain centrioles and pericentriolar substance which facilitates tubulin assembly by somehow lowering Cc. Centrioles are the common structure in...
Ion Beam Lithography
In analogy with the use of electrons, ions can also be applied for lithography 91 . They too can be generated as well as accelerated by the electrode arrangements, filtered according to their energy and locally guided by electronic optics. Ion beams are utilized in four directions of nanolithography - to fabricate structures in ion-beam-sensitive resists - for structure transfer from structured resist layers in functional layer by ion beam etching - to structure directly by local etching using...
Holographic datastorage system HDSS
The late twentieth century had some pretty fancy dreams. For example, the 1978 movie Superman flew fantastic special effects at audiences faster than a speeding bullet including a glowing green crystal (a gift from Superman's alien father) that created the Fortress of Solitude at the North Pole complete with a data-retrieval system that housed the entire history of Superman's home planet and all the engineering smarts needed to create that crystal palace. (Automatically, at that.) Impressive as...
Disadvantages of Polymeric Nanoparticles
Although polymeric nanoparticles have many advantages such as various fabrication methods, versatile drug loading, and drug release methods , they still have some drawbacks. The main limitation is that some preparation methods use toxic organic solvents that could degrade certain drugs when they come into contact during the formulation process or could be hazardous to the environment as well as to the physiological system Birnbaum et al. 2000 . Other disadvantages include poor drug...
Force probes in a bottle
A rigid molecule that changes shape when exposed to light can be used to explore the influence of mechanical force on chemical reactions involving small functional groups. Jeremy M. Lenhardt and Stephen L. Craig Figure 1 Molecular force probes are synthesized by forming a relatively unstrained ring that is then photochemically switched into a highly strained state. The force probe, stiff stilbene, is shown in red and the reacting group (trans-3,4-dimethylcyclobutene trans,trans-2,4-hexadiene)...
High Pressure Origin Of Diamond
As early as 1694, Florentine academicians suspected that diamond was made of carbon when they found that the precious stone could be burned completely in air. In 1772, this speculation was confirmed by the French chemist Antoine Lavoisier who discovered that the gas released from a burnt diamond was indeed carbon dioxide. In 1797, Smithson Tennant proved beyond any doubt that diamond is made of carbon by burning a diamond in pure oxygen. He measured the amount of carbon dioxide released and...
Graphite and Its Structure
The structure of graphite had been elucidated from 1917 on by Debye, Scherrer, Grimm, Otto, and Bernal. It is characterized by a succession of distinct so-called graphene layers that spread over an xy-plane. They are stacked in a z-direction, and there are only weak van der Waals interactions among them (Figure 1.7). Within one graphene layer, the carbon atoms are situated at the corners of regular hexagons that constitute a two -dimensional lattice. From each C -atom there are three o-bonds...
Commercial Production Of Diamond Superabrasives
Natural diamond was the only superabrasive capable to machine tungsten carbide tools before 1957. During the World War I, the consumption of natural diamond surged to 0.4 ton a year. When World War II broke out, this demand increased drastically to 4 tons per year. At then only South Africa can export natural diamond, so US has stocked piled strategic supply of natural diamond that was released only after 2000. In 1941, Percy Bridgman was supported by General Electric, Norton, and Carborandum...
Applications Of Zeta Potential And Electrophoretic Mobility
As mentioned earlier, the zp is a good indicator to explain the stability mechanisms of different colloidal Fig. 6 Total energy of interaction curves for silica particles and their corresponding coagulation behavior. Source From Ref. 48 . Fig. 6 Total energy of interaction curves for silica particles and their corresponding coagulation behavior. Source From Ref. 48 . and emulsion systems, and the adsorption mechanism between any organic or inorganic species at any solid-liquid interface. The...
Interaction Mechanisms Between Mineral Particles
DLVO Theory and the Interaction Energy Curves The DLVO (Derjaguin and Landau, 1941 44 Verwey and Overbeek, 1948 45 ) theory explains the stability of colloidal systems including nanosized particles considering the total potential energy of interaction between colloidal particles depending on the distance between them. The total or net interaction energy is equal to the summation of the EDL interaction energy (VER) and the van der Walls interaction energy (VVA) and given as The EDL interaction...
Chemical shrink of dark field structures
The resist thinning method does not work for dark field patterns any loss of linewidth will result in wider structures. A poor man's method of small DF structures is based on resist flow resist will flow when heated above glass-transition temperature. This flow will, under favourable conditions, make holes and trenches smaller in a controlled fashion. This method has been successfully used in contact hole scaling studies. A more advanced version for making narrow dark field patterns consists of...
Silicon Dioxide
Silicon dioxide (SiO2) is one of the most widely used materials in the fabrication of MEMS. In polysilicon surface micromachining, SiO2 is used as a sacrificial material, since it can be easily dissolved using etchants that do not attack polysilicon. SiO2 is widely used as etch mask for dry etching of thick polysilicon films, since it is chemically resistant to dry etching processes for polysilicon. SiO2 films are also used as passivation layers on the surfaces of environmentally sensitive...
Application Of Focused Ion Beam Instrumentation
Thus far, we have discussed in depth the tremendous power of the FIB machine, with its wide-ranging functions and capabilities. Yet the capabilities by themselves are not the direct reason for the great industrial interest in FIB technology instead, it is the abundance of applications yielded by these capabilities that have given rise to excitement. These applications seem to come with a promise of commercial success, and will therefore be discussed in detail in this review. We will begin with...
Processing Of Infrared Photodetectors
An infrared FPA device consists of two parts. The first one is the sensor array which is used to convert the infrared radiation into the electrically readable signal. In a QWIP, this signal is the photocurrent. The second part of the QWIP is the electrical circuit array, also called the readout circuit (ROC), which is used to transfer the electrically readable signals generated in very pixels of the array in a series manner. Such a signal transferring mode is very convenient for further data...