Chemical Nanotechnology:
Molecular Electronics
Introduction
The ability to build products by molecular manufacturing would create a radical improvement in the manufacture of technologically advanced products. Everything from computers to weapons to consumer goods, and even desktop factories, would become incredibly cheap and easy to build. If this is possible, the policy implications are enormous.
Richard Smalley, a prominent nanotechnologist, has tried for several years to debunk this possibility. Most recently, he participated in apublished exchange with Eric Drexler, another prominent nanotechnologist, who has been the primary proponent and theorist of molecular manufacturing (also called molecular nanotechnology, or MNT).
This paper examines the arguments presented by each side and concludes that Smalley has failed to support his opinion that MNT cannot work as Drexler asserts. Much of Smalley’s discussion is off-topic, and his assertions about the limitations of enzyme chemistry are factually incorrect—a fatal weakness in his argument. He therefore does not provide a useful criticism of MNT. Trying to bring the debate back on topic, Drexler spends most of his time restating his earlier positions. Despite these problems, the current exchange represents a significant advance in the debate, since Smalley’s new focus on realistic chemistry (instead of the earlier “magic fingers”) permits detailed analysis of the technical merits of his claim.
The Term Paper on Organic Molecules Challenge Molecular Electron
Organic Molecules Challenge Silicon's Reign as King of Semiconductors There is a revolution fomenting in the semiconductor industry. It may take 30 years or more to reach perfection, but when it does the advance may be so great that today's computers will be little more than calculators compared to what will come after. The revolution is called molecular electronics, and its goal is to depose ...
The answer to the question of MNT’s capabilities will have a large effect on nanotechnology policy, and further research is urgently needed to find this answer. Smalley’s factual inaccuracies and continued failure to criticize the actual chemical proposals of MNT strongly suggest that his denial of the possibility may be unfounded. In view of this, while we agree with Smalley that some scenarios of molecular manufacturing are worrisome, we reject his conclusion that the possibility of MNT should be denied in order to avoid scaring children. This paper reviews the history of the MNT debate, analyzes the technical arguments on both sides, then briefly discusses the feasibility and desirability of further research and the potentially disastrous implications of continuing to ignore the possibility of molecular manufacturing.
Will chemistry play a role in nanotechnology?
It should be bracing to chemists to realize that chemistry is already playing a leading role in nanotechnology. In a sense, chemistry is (and has always been) the ultimate nanotechnology: Chemists make new forms of matter (and they are really the only scientists to do so routinely) by joining atoms and groups of atoms together with bonds. They carry out this subnanometer-scale activity—chemical synthesis— on megaton scales when necessary, and do so with remarkable economy and safety. Although the initial interest in nanotechnology centered predominantly on nanoelectronics, and on fanciful visions of the futurists, the first new and potentially commercial technologies to emerge from revolutionary nanoscience seem, in fact, to be in materials science; and materials are usually the products of chemical processes. Some examples follow below
Scope
The activities and interests of Group will include all areas of
chemical nanoscience and nanotechnology. For example:
• The fabrication and utilisation of novel nanostructured materials.
• The fabrication and utilisation of novel nanoparticle materials including metal, oxide and other inorganic systems.
• The fabrication of carbon and inorganic nanotubes and fullerenes and their utilisation in technological processes.
• The fabrication and utilisation of novel nanostructures using bottom-up self-assembly processes.
The Term Paper on Due Process Models
The existence of a political body can be framed on account the need to regulate human actions. Just the same, the force of criminal process is in place to protect the society from malicious intents of erring individuals. Two models of criminal process – the Crime Control and Due Process – therefore merit attention in this discussion. On the one hand, Crime Control emphasizes swift action ...
• The development of top-down lithographic processes and materials to fabricate nanostructured surfaces.
• The integration of bottom-up self-assembly processes with top-down lithographic processes to create three dimensional functioning and adaptive nanostructures.
• The fabrication and utilisation of novel nanostructured surfaces,
• The fabrication and utilisation of novel quantum dots in technological processes.
• The fabrication and utilisation of novel biologically relevant nanostructures.
• Investigation of the property-size relationship at the nanoscale.
• Health, safety and environmental implications of chemical nanoscience and nanotechnology.
Nanotubes
A one dimensional fullerene (a convex cage of atoms with only hexagonal and/or pentagonal faces) with a cylindrical shape. Carbon nanotubes discovered in 1991 by Sumio Iijima resemble rolled up graphite, although they can not really be made that way. Depending on the direction that the tubes appear to have been rolled (quantified by the ‘chiral vector’), they are known to act as conductors or semiconductors. Nanotubes are a proving to be useful as molecular components for nanotechnology. Strictly speaking, any tube with nanoscale dimensions, but generally used to refer to carbon nanotubes, which are sheets of graphite rolled up to make a tube. A commonly mentioned non-carbon variety is made of boron nitride, another is silicon. These noncarbon nanotubes are most often referred to as nanowires. The dimensions are variable (down to 0.4 nm in diameter) and you can also get nanotubes within nanotubes, leading to a distinction between multi-walled and single-walled nanotubes. Apart from remarkable tensile strength, nanotubes exhibit varying electrical properties (depending on the way the graphite structure spirals around the tube, and other factors, such as doping), and can be superconducting, insulating, semiconducting or conducting (metallic).
[CMP] Nanotubes can be either electrically conductive or semiconductive, depending on their helicity, leading to nanoscale wires and electrical components. These one-dimensional fibers exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond, strength 100 times greater than steel at one sixth the weight, and high strain to failure. A nanotube’s chiral angle–the angle between the axis of its hexagonal pattern and the axis of the tube–determines whether the tube is metallic or semiconducting. Nanotubes Under Stress.A graphene sheet can be rolled more than one way, producing different types of carbon nanotubes. The three main types are armchair, zig-zag, and chiral. Examples
The Essay on Forms Of Steel Carbon Iron Properties
Informative Speech - Metals Purpose: My purpose is to inform the audience of how different types of steel are formed by explaining the different mechanical properties of Iron and Carbon compositions. I. Introduction A. Have you ever noticed that some steel, such as a long bridge is able to bend and have slack, whereas other types of steel are more brittle yet much harder, such as a propeller. If a ...
Carbon nanotubes possess many unique properties which make them ideal AFM probes. Their high aspect ratio provides faithful imaging of deep trenches, while good resolution is retained due to their nanometer-scale diameter. These geometrical factors also lead to reduced tip-sample adhesion, which allows gentler imaging. Nanotubes elastically buckle rather than break when deformed, which results in highly robust probes. They are electrically conductive, which allows their use in STM and EFM (electric force microscopy), and they can be modified at their ends with specific chemical or biological groups for high resolution functional imaging.
CNT exhibits extraordinary mechanical properties: the Young’s modulus is over 1 Tera Pascal. It is stiff as diamond. The estimated tensile strength is 200 Giga Pascal. These properties are ideal for reinforced composites, nanoelectromechanical systems (NEMS).
carbon nanotube Transistors exploit the fact that nm- scale nanotubes (NT) are ready-made molecular wires and can be rendered into a conducting, semiconducting, or insulating state, which make them valuable for future nanocomputer design. … Carbon nanotubes are quite popular now for their prospective electrical, thermal, and even selective-chemistry applications.
Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.
The Term Paper on Microporosity And Surface Functionality Of Activated Carbon
Abstract Activated carbons have been prepared from jute stick by both chemical and physical activation methods using ZnCl2 and steam, respectively. The activated carbons were characterized by evaluating surface area, iodine number, pore size distribution, surface functional groups and surface textural properties. Based on the analysis, the activated carbon prepared by chemical activation method, ...
structure of a multi-
Fig.- (a)walled nanotube FigFig.-(b) Fig
carbon nanotube with metal-semiconductor junction n
Fig.-(a) shows carbon nanotube with metal semi-conductor junction
Fig.-(b) shows structure of multiwalled nanotube
Bucky balls
“It is the roundest and most symmetrical large molecule known to man. Buckministerfullerine continues to astonish with one amazing property after another. Named after American architect R. Buckminister Fuller who designed a geodesic dome with the same fundamental symmetry, C60 is the third major form of pure carbon; graphite and diamond are the other two.” Bucky Balls – Andy Gion.
AKA: C60 molecules & buckminsterfullerene. Molecules made up of 60 carbon atoms arranged in a series of interlocking hexagons and pentagons, forming a structure that looks similar to a soccer ball [Steffen Weber, PhD.]. C60 is actually a “truncated icosahedron”, consisting of 12 pentagons and 20 hexagons. It was discovered in 1985 by Professor Sir Harry Kroto, and two Rice University professors, chemists Dr. Richard E. Smalley and Dr. Robert F. Curl Jr., [for which they were jointly awarded the 1996 Nobel Lauriate for chemistry] and is the only molecule composed of a single element to form a hollow spheroid [which gives the potential for filling it, and using it for novel drug-delivery systems. See Structure of a New Family of Buckyballs Created].
“The buckyball, being the roundest of round molecules, is also quite resistant to high speed collisions. In fact, the buckyball can withstand slamming into a stainless steel plate at 15,000 mph, merely bouncing back, unharmed. When compressed to 70 percent of its original size, the buckyball becomes more than twice as hard as its cousin, diamond.” The Buckyball – Rodrigo de Almeida Siqueira
Nanofabrication
As the critical dimensions in microelectronics have shrunk, the complex technologies necessary to circumvent the limitations on size imposed by optical diffraction has made photolithography increasingly complicated and expensive. Surprisingly, technologies that are very familiar in chemistry—printing, molding, and embossing—have emerged (in the forms of soft lithography and nanoimprint
The Essay on Fullerenes Molecule Carbon Molecules
Overall View of Fullerenes Natural Carbons can usually exist in several forms. The most common are Graphite and diamond, but most people don t know that there is a third type fullerenes. Many have mistaken these fullerenes for a new type of carbon. Fullerenes have been discovered in interstellar dust as well as in geological formations on Earth, but they are very new to us. As with many important ...
lithography) as potential competitors for (or complements
to) photolithography. The intrinsic limitations to the sizes of the patterns that can be replicated using printing and molding is set by van der Waals interactions, and perhaps by the granularity of matter at the molecular scale, but certainly not by optical diffraction. Self-assembly—a strategy best understood and most highly developed in chemistry—is also offering an appealing strategy for fusing
“bottom-up” and “top-down” fabrication, and leading to hierarchical structures of the types so widely found in nature Electrochemistry in the pores of membranes provides a widely useful route to nanoscale rods
These materials (affectionately known as “SAMs” by
those who work with them) are formed by allowing appropriate surfactants to assemble on surfaces (again, soap chemistry! See Figure 5).[47–49] They provide synthetic routes to nanometer-thick, highly structured films on surfaces that provide biocompatibility, control of corrosion, friction, wetting, and adhesion, and may offer routes to possible nanometer- scale devices for use in “organic microelectronics”. They have also changed the face of surface science as a research enterprise, moving it from the study of metals and metal oxides in high vacuum to the study of organic materials in circumstances more closely approximating the real world.
