NANOTECHNOLOGY CHAPTER 1::INTRODUCTION

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1 ABSTRACT Nano-RAM is a proprietary computer memory technology from the company Nantero and NANOMOTOR is invented by University of bologna and California nano systems. NRAM is a type of nonvolatile random access memory based on the mechanical position of carbon nanotubes deposited on a chip-like substrate. In theory the small size of the nanotubes allows for very high density memories. Nantero also refers to it as NRAM in short, but this acronym is also commonly used as a synonym for the more common NVRAM, which refers to all nonvolatile RAM memories.nanomotor is a molecular motor which works continuously without the consumption of fuels. It is powered by sunlight. The researches are federally funded by national science foundation and national academy of science. Carbon Nanotubes Carbon nanotubes (CNTs) are a recently discovered allotrope of carbon.they take the form of cylindrical carbon molecules and have novel properties that make them potentially useful in a wide variety of applications in nanotechnology, electronics, optics, and other fields of materials science. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized. A nanotube is a member of the fullerene structural family, which also includes buckyballs. Whereas buckyballs are spherical in shape, a nanotube is cylindrical, with at least one end typically capped with a hemisphere of the buckyball structure. Page 1

2 CHAPTER 1::INTRODUCTION NANOTECHNOLOGY There's an unprecedented multidisciplinary convergence of scientists dedicated to the study of a world so small, we can't see it -- even with a light microscope. That world is the field of nanotechnology, the realm of atoms and nanostructures. Nanotechnology is so new, no one is really sure what will come of it. Even so, predictions range from the ability to reproduce things like diamonds and food to the world being devoured by self-replicating nanorobots. In order to understand the unusual world of nanotechnology, we need to get an idea of the units of measure involved. A centimeter is one-hundredth of a meter, a millimeter is one-thousandth of a meter, and a micrometer is one-millionth of a meter, but all of these are still huge compared to the nanoscale. A nanometer (nm) is onebillionth of a meter, smaller than the wavelength of visible light and a hundredthousandth the width of a human hair. As small as a nanometer is, it's still large compared to the atomic scale. An atom has a diameter of about 0.1 nm. An atom's nucleus is much smaller -- about nm. Atoms are the building blocks for all matter in our universe. You and everything around you are made of atoms. Nature has perfected the science of manufacturing matter molecularly. For instance, our bodies are assembled in a specific manner from millions of living cells. Cells are nature's nanomachines. At the atomic scale, elements are at their most basic level. On the nanoscale, we can potentially put these atoms together to make almost anything. In a lecture called "Small Wonders: The World of Nanoscience," Nobel Prize winner Dr. Horst Störmer said that the nanoscale is more interesting than the atomic scale because the nanoscale is the first point where we can assemble Page 2

3 something -- it's not until we start putting atoms together that we can make anything useful. Experts sometimes disagree about what constitutes the nanoscale, but in general, you can think of nanotechnology dealing with anything measuring between 1 and 100 nm. Larger than that is the microscale, and smaller than that is the atomic scale. Nanotechnology is rapidly becoming an interdisciplinary field. Biologists, chemists, physicists and engineers are all involved in the study of substances at the nanoscale. Dr. Störmer hopes that the different disciplines develop a common language and communicate with one another [source: Störmer]. Only then, he says, can we effectively teach nanoscience since you can't understand the world of nanotechnology without a solid background in multiple sciences. One of the exciting and challenging aspects of the nanoscale is the role that quantum mechanics plays in it. The rules of quantum mechanics are very different from classical physics, which means that the behavior of substances at the nanoscale can sometimes contradict common sense by behaving erratically. You can't walk up to a wall and immediately teleport to the other side of it, but at the nanoscale an electron can -- it's called electron tunneling. Substances that are insulators, meaning they can't carry an electric charge, in bulk form might become semiconductors when reduced to the nanoscale. Melting points can change due to an increase in surface area. Much of nanoscience requires that you forget what you know and start learning all over again. At the nanoscale, objects are so small that we can't see them -- even with a light microscope. Nonscientists have to use tools like scanning tunneling microscopes or atomic force microscopes to observe anything at the nanoscale. Scanning tunneling microscopes use a weak electric current to probe the scanned material. Atomic force microscopes scan surfaces with an incredibly fine tip. Both microscopes send data to computer, which can assemble the information and project it graphically onto a monitor. Page 3

4 NANO-RAM Basically in NANO-RAM, there are two words of different technologies and are attached together. First one is the Nanotechnology and second one is the Ramdom access memory. We have already taken information about the nanotechnology, lets see what is RAM. What these both contribute to the new research called NANO-RAM. Random-access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order (i.e., at random). "Random" refers to the idea that any piece of data can be returned in a constant time, regardless of its physical location and whether or not it is related to the previous piece of data. By contrast, storage devices such as magnetic discs and optical discs rely on the physical movement of the recording medium or a reading head. In these devices, the movement takes longer than data transfer, and the retrieval time varies based on the physical location of the next item. Most forms of modern random access memory (RAM) are volatile storage, including dynamic random access memory (DRAM) and static random access memory (SRAM). Content addressable memory and dual-ported RAM are usually implemented using volatile storage. Early volatile storage technologies include delay line memory and William s tube. Volatile memory, also known as volatile storage, is computer memory that requires power to maintain the stored information, unlike non-volatile memory which does not require a maintained power supply. It has been less popularly known as temporary memory. Page 4

5 Nano-Ram is the new era memory which is not now yet completely discovered but it shows a light towards the new age of electronics which totally has a new look and working strategies. It now travels from micrometer to nanometer with a great working capabilities and strengths. Nano-RAM is a proprietary computer memory technology from the company Nantero and NANOMOTOR is invented by University of bologna and California nano systems. RAM is a type of nonvolatile random access memory based on the mechanical position of carbon nanotubes deposited on a chip-like substrate. In theory the small size of the nanotubes allows for very high density memories. Nantero also refers to it as NRAM in short, but this acronym is also commonly used as a synonym for the more common NVRAM, which refers to all nonvolatile RAM memories. Nanomotor is a molecular motor which works continuously without the consumption of fuels. It is powered by sunlight. The research is federally funded by national science foundation and national academy of science. Page 5

6 CARBON NANOTUBES The term nanotubes is normally used to refer to the carbon nanotubes, which has received enormous attention from researchers over the last few years and promises, along with close relatives such as the nanohorn, a host of interesting applications. There are many others types of nanotubes, from various inorganic kinds such as, those made from boron nitride, to organic ones, such as those made from self-assembling cyclic peptides (proteins components) or from naturally occurring heat shock proteins(extracted from bacteria that thrive in extreme environments). However, carbon nanotubes excites the most interest, promise the greatest variety of application and currently appear to have by far the highest commercial potential. Carbon nanotubes were discovered in 1991 by Sumio Iijima of NEC and are effectively long, thin cylinders of graphite, which you wiil be familiar with as the material in a pencil or as the basis of some lubricants. Graphite is made up of layers of carbon atoms arranged in a hexagonal lattice, like chicken wire. Though the chicken wire structure itself is very strong, the layers themselves sure not chemically bonded to each other but held together by weak forces called Van der Waals. It is the sliding across each other of these layers that gives graphite its lubricating qualities and makes the mark on a piece of paper as you draw your pencil over it. Now imagine taking one of these sheets of chicken wire and rolling it up into a cylinder and joining the loose wore ends. The result is a tube that was once described by Richard Smalley (who shared the Nobel Prize for the discovery of a related form of carbon called buckminsterfullerene) as In one direction.the strongest damn thing you ll ever make in this universe. In addition to their remarkable strength, this is usually quoted a 100 times that of steel at onesixth of the weight (this is tensile strength-the ability to withstand a stretching force without breaking), carbon nanotubes have shown a surprising array of other properties. They can Page 6

7 conduct heat as efficiently as diamond, conduct electricity as efficiently as copper, yet also be semiconducting (like the materials that make up the chips in our computers). They can produce streams of electrons very efficiently (field emission), which can be used to create light in displays for televisions or computers, or even in domestic lighting, and they can enhance the fluorescence of materials they are close to. Their electrical properties can be made to change in the presence can act like miniature springs and they can even be stuffed with other material. Nanotubes and their variants hold promise for storing fuels such as hydrogen or methanol for use in fuel cells and they make good support for catalysts. Page 7

8 CHAPTER 2::CARBON NANOTUBES STRUCTURE OF CARBON NANOTUBES Carbon nanotubes (CNTs; also known as buckytubes) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1 ] which is significantly larger than any other material. These cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential uses in architectural fields. They exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors. The nature of the bonding of a nanotube is described by applied quantum chemistry, specifically, orbital hybridization. The chemical bonding of nanotubes is composed entirely of sp 2 bonds, similar to those of graphite. This bonding structure, which is stronger than the sp 3 bonds found in diamonds, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces. Since carbon nanotubes were discovered on accident by Sumio Iijima in 1991 during another experiment, hundreds of studies have been started and dedicated to achieving a better understanding of the structure of carbon nanotubes. Although the structure of carbon nanotubes has been extensively studied by researchers and scientists in a wide variety of fields including materials science, architecture, agriculture and engineering, the full implications of this tiny microscopic wonder are still locked away in its unique natural creation, varied structural components and its ability to be both immensely flexible as well as incredibly strong. Carbon comes in many forms. Two well-known forms of carbon are graphite and Page 8

9 diamond. Graphite and diamond have drastically different mechanical properties such as hardness. Diamond is one of the hardest materials known to man. It can cut through glass. Graphite, on the other hand, is a very soft material, used in pencil lead. The difference in properties is due to the structure of the atoms and their bonds in the material, also known as the materials crystal structure. Graphite is made up of stacked sheets of hexagons with a carbon atom at each corner of the hexagon, and looks much like chicken wire. These sheets are stacked one on top of the other, but easily slip and slide. Diamond has a tetragonal crystal structure with very few slip planes. Carbon nanotubes are a fairly new form of carbon. A carbon nanotube structure looks like sheets of graphite that have been rolled up to form small tubes. This small difference in structure leads to a much stronger, stiffer material. Carbon nanotubes have a diameter of 1 to 10 nanometers, yet they are 50 times stronger than steel. The special nature of carbon combines with the molecular perfection of buckytubes (single-wall carbon nanotubes) to endow them with exceptionally high material properties such as electrical and thermal conductivity, strength, stiffness, and toughness. No other element in the periodic table bonds to itself in an extended network with the strength of the carbon-carbon bond. The delocalised pi-electron donated by each atom is free to move about the entire structure, rather than stay home with its donor atom, giving rise to the first molecule with metallic-type electrical conductivity. The high-frequency carbon-carbon bond vibrations provide an intrinsic thermal conductivity higher than even diamond. In most materials, however, the actual observed material properties - strength, electrical conductivity, etc. - are degraded very substantially by the occurrence of defects in their structure. For example, high strength steel typically fails at about 1% of its theoretical breaking strength. Page 9

10 Buckytubes, however, achieve values very close to their theoretical limits because of their perfection of structure - their molecular perfection. This aspect is part of the unique story of buckytubes. Buckytubes are an example of true nanotechnology: only a nanometer in diameter, but molecules that can be manipulated chemically and physically. They open incredible applications in materials, electronics, chemical processing and energy management. Basic Structure Buck tubes are single-wall carbon nanotubes, in which a single layer of graphite - graphene - is rolled up into a seamless tube. Graphene consists of a hexagonal structure like chicken wire. If you imagine rolling up graphene or chicken wire into a seamless tube, this can be accomplished in various ways. For example, carbon-carbon bonds (the wires in chicken wire) can be parallel or perpendicular to the tube axis, resulting in a tube where the hexagons circle the tube like a belt, but are oriented differently. Alternatively, the carbon-carbon bonds need not be either parallel or perpendicular, in which case the hexagons will spiral around the tube with a pitch depending on how the tube is wrapped. Above figure illustrates these point. Carbon nanotubes appear to be sheets of graphite cells that have been mended together to look almost like a latticework fence and then rolled up in a tube shape. Although this is a simple explanation for the look of the structure of carbon nanotubes, this is not how carbon nanotubes are created, nor does it explain their immense strength or other incredible structural abilities. Page 10

11 CLASSIFICATION OF CARBON NANOTUBES One of the major classifications of carbon nanotubes is into singledwalled varieties (SWNT s) which have a single cylinder wall and multi-walled varieties (MWNT s) which have cylinders within cylinders. The length of both type vary greatly, depending upon on the way they are made and are generally nanoscopic rather than microscopic i.e. greater than 100 micrometers. The aspect ratio (length divided by diameter) is typically greater than100 and can be up to 10,000, but recently even this was made to look small. IN May 2002, SWNT strand were made in which the SWNT s were claimed to be as long as 20 cm. Even more recently, the same group has made strand of SWNT s 160cm long, but the precise make up of these strand has not yet been made clear. A group in china has found, purely by accident that packs of relatively short carbon nanotubes can be drawn out into a bundle of fibers, making a thread only 0.2 mm in diameter but up to 30 cm long. The joins between the nanotubes in this thread represent a weakness but heating the thread has been found to increase the strength significantly, presumably through some sort of fusing of the individual tubes. SINGLE-WALLED CARBON NANOTUBES (SWNT S) Single-wall nanotubes (SWNT) are tubes of graphite that are normally capped at the ends. They have a single cylindrical wall. The structure of a SWNT can be visualized as a layer of graphite, a single atom thick, called graphene, which is rolled into a seamless Page 11

12 cylinder.most SWNT typically have a diameter of close to 1 nm. The tube length, however, can be many thousands of times longer. SWNT are more pliable yet harder to make than MWNT. They can be twisted, flattened, and bent into small circles or around sharp bends without breaking. SWNT have unique electronic and mechanical properties which can be used in numerous applications, such as fieldemission displays, nanocomposite materials, nanosensors, and logic elements. These materials are on the leading-edge of electronic fabrication, and are expected to play a major role in the next generation of miniaturized electronics. The ability of single-walled carbon nanotubes to bend at the extreme angle observed in figure 1opened the possibility that the proposed structure of SWNTs was not accurate since it is suspicious that a cylinder composed of a closed graphitic sheet could bend that far without visible damage to the tube. SWNT s can be conducting like metal or semiconducting and taking into account their small diameter and their huge aspect ratio, SWNT s are close to an ideal one dimensional system. The general composition of SWNT s COMPOSITION OF SWNTs Average outside diameter: 1.1 nm Length: 5-30 mm Components Contents (%) C Al 0.08 Cl 0.41 Co 2.91 S 0.29 Analysis Method: Energy Dispersive X-ray Spectroscopy Page 12

13 MULTI-WALLED CARBON NANOTUBES (MWNT s) Multi-walled carbon nanotubes are basically concentric cylindrical graphite tubes. In these more complex structures, the different SWNT s that form the MWNT may have quite different structures by length and chirality). MWNT s are typically 100 times longer than they are wide and have outer diameter mostly in the tens of nanometer. Although it is easier to produce significant quantities of MWNT s than SWNTs, their structures are less well understood than SWNT because of their greater complexity and variety. Multitudes of exotic shapes and arrangement, often with imaginative names such as bamboo-trunks, sea urchins etc. Many of the nanotube application now being considered or put into practice involve multi-walled nanotubes, because they are easier to produce in large quantities at a reasonable price and have been available in decent amount for much longer than SWNTs. They involve typically 8 to 15 walls and around 19 nanometers wide and 10 micrometer long. Many companies are moving into this space, notably formidable players like Mitsui, with plans to produce similar types of MWNT in hundred of tons a year, a quantity that is greater but not hugely so that the current production of Hyperion Catalysis. This is an indication that even these less impressive and exotic nanotubes hold promise of representing a sizable market in the near future. The composition of MWNT s is as shown in table: COMPOSITION OF MWNTs Page 13

14 Outside diameter: 8 nm Inside diameter: 2-5 nm Length: µm Components Contents (%) C Al 0.19 Cl 1.03 Co 1.10 S 0.24 Analysis Method: Energy Dispersive X-ray Spectroscopy BENEFITS OF CARBON NANOTUBES The underlying excitement over CNTs comes from their wide range of behaviors and properties. By learning about the properties of CNTs, it is possible to imagine enormous possibilities for their application. Strength and Elasticity: CNTs can be really strong. Their tensile strength, a measure of the amount of force which a specimen can withstand before tearing, is approximately 100 times greater than that of steel. Strength of CNTs results from the covalent sp² bonds formed between the individual carbon atoms. This bond is stronger than the sp 3 bond in diamonds. CNTs are held together by Van der Waals forces, forming a rope-like structure [10]. Another reason why they are so strong is because they are just one large molecule. Unlike other materials, carbon nanotubes do not have weak-spot, such as steel. CNTs also have a high elastic modulus, a measure of the material s tendency to deform elastically when a force is applied to it. Electrical and Magnetic: Metallic-like CNTs are better conductors than metals. The only other materials that can conduct better than CNTs are superconductors, which theoretically have zero electrical Page 14

15 resistance. It has also been observed that, under the influence of a large magnetic field, the band gap of semi-conducting CNTs can be slightly lowered. Optical: A defect-free carbon nanotube is like an optical fiber. Fibers with large cores are called multi-mode fibers because several wavelengths (or eigenmodes) are allowed to propagate, usually at different speeds, along the fiber. For data transmission, so-called single-mode fibers are preferred because they allow for higher data rates. A single-wall nanotube is almost a single-mode fiber for electrons. Theory predicts the existence of two propagating eigenmodes for a single-wall nanotube, independent of its diameter. Chemical: The chemical reactivity of a CNT is, compared with a graphene sheet, enhanced as a direct result of the curvature of the CNT surface. Carbon nanotube reactivity is directly related to the pi-orbital mismatch caused by an increased curvature. Therefore, a distinction must be made between the sidewall and the end caps of a nanotube. For the same reason, a smaller nanotube diameter results in increased reactivity. Covalent chemical modification of either sidewalls or end caps has been shown to be possible Page 15

16 CHAPTER 3:: NANO-RAM STRUCTURE OF NANO-RAM Nano-RAM is a proprietary computer memory technology from the company Nantero and NANOMOTOR is invented by University of bologna and California nano systems. RAM is a type of nonvolatile random access memory based on the mechanical position of carbon nanotubes deposited on a chip-like substrate. In theory the small size of the nanotubes allows for very high density memories. Nantero also refers to it as NRAM in short, but this acronym is also commonly used as a synonym for the more common NVRAM, which refers to all nonvolatile RAM memories. Nanomotor is a molecular motor which works continuously without the consumption of fuels. It is powered by sunlight. The researches are federally funded by national science foundation and national academy of science. The design is quite simple. Nanotubes can serve as individually addressable electromechanical switches arrayed across the surface of a microchip, storing hundreds of gigabits of information may be even a terabit. An electric field applied to nanotubes would cause it to flex downward into depression etched onto the chip s surface, where it would contact rather another nanotube or touch a metallic electrode. Once bent, the nanotubes can remain that way, including when the power is turned off, allowing for non-volatile operation. Vanderwaals forces, which are weak molecular forces of attractions, would hold the switch in place until application of fields of different polarity causes the nanotube to return to its straightened position. Page 16

17 This nano electromechanical memory, called NRAM, is a memory with actual moving parts, with dimensions measured in nanometers. Its carbon nanotube based technology makes advantage of vaanderwaals force to create basic on off junctions of a bit. Vaanderwaals forces interaction between atoms that enable noncovalant binding. They rely on electron attractions that arise only at nano scale levels as a force to be reckoned with. The company is using this property in its design to integrate nanoscale material property with established cmos fabrication technique. Nantero's technology is based on a well-known effect in carbon nanotubes where crossed nanotubes on a flat surface can either be touching or slightly separated in the vertical direction (normal to the substrate) due to Van der Waal's interactions. In Nantero's technology, each NRAM "cell" consists of a number of nanotubes suspended on insulating "lands" over a metal electrode. At rest the nanotubes lie above the electrode "in the air", about 13 nm above it in the current versions, stretched between the two lands. A small dot of gold is deposited on top of the nanotubes on one of the lands, providing an electrical connection, or terminal. A second electrode lies below the surface, about 100 nm away. NRAMs are built by depositing masses of nanotubes on a pre-fabricated chip containing rows of bar-shaped electrodes with the slightly taller insulating layers between them. Tubes in the "wrong" location are then removed, and the gold terminals deposited on top. Any number of methods can be used to select a single cell for writing, for instance the second set of electrodes can be run in the opposite direction, forming a grid, or they can be selected by adding voltage to the terminals as well, meaning that only those selected cells have a total voltage high enough to cause the flip. Currently the method of removing the unwanted nanotubes makes the system impractical. The accuracy and size of the epitaxial machinery is considerably "larger" that the cell size otherwise possible. Existing experimental cells have very low densities Page 17

18 compared to existing systems, some new method of construction will have to be introduced in order to make the system practical. As we see the structure and the construction of the Nano-Ram, now let study how the data is being stored in ths Nano-Ram. STORAGE IN NANO-RAM Nantero has created multiple prototype devices, including an array of ten billion suspended nano tube junctions on a single silicon wafer. NRAM technology will achieve very high memory densities: at least times our current best. Nantero's design for NRAM involves the use of suspended nanotube junctions as memory bits, with the "up" position representing bit zero (Off) and the "down" position representing bit one (On). Bits are switched between states through the application of electrical fields. The wafer (A small adhesive disk of paste) was produced using only standard semiconductor processes, maximizing compatibility with existing semiconductor factories. NRAM works by balancing the on ridges of silicon. Under differing electric charges, the tubes can be physically swung into one or two positions representing one and zeros. Because the tubes are very small-under a thousands of time-this movement is very fast and needs very little power, and because the tubes are a thousand times conductive as copper it is very to sense to read back the data. Once in position the tubes stay there until a signal resets them. The bit itself is not stored in the nano tubes, but rather is stored as the position of the nanotube. Up is bit 0 and down is bit 1.Bits are switched between the states by the application of the electric field. The technology work by changing the charge placed on a latticework of crossed nanotube. By altering the charges, engineers can cause the tubes to bind together or separate, creating ones and zeros that form the basis of computer memory. If we have two Page 18

19 nano tubes perpendicular to each other one is positive and other negative, they will bend together and touch. If we have two similar charges they will repel. These two positions are used to store one and zero. The chip will stay in the same state until you make another change in the electric field. So when you turn the computer off, it doesn't erase the memory.we can keep all the data in the NRAM and gives your computer an instant boot. What causes this to act as a memory is that the two positions of the nanotubes are both stable. In the off position the mechanical strain on the tubes is low, so they will naturally remain in this position and continue to read "0". When the tubes are pulled into contact with the upper electrode a new force, the tiny Van der Waals force, comes into play and attracts the tubes enough to overcome the mechanical strain. Once in this position the tubes will again happily remain there and continue to read "1". These positions are fairly resistant to outside interference like radiation that can erase or flip memory in a conventional DRAM. NRAMs are built by depositing masses of nanotubes on a pre-fabricated chip containing rows of bar-shaped electrodes with the slightly taller insulating layers between them. Tubes in the "wrong" location are then removed, and the gold terminals deposited on top. Any number of methods can be used to select a single cell for writing, for instance the second set of electrodes can be run in the opposite direction, forming a grid, or they can be selected by adding voltage to the terminals as well, meaning that only those selected cells have a total voltage high enough to cause the flip. Page 19

20 ADVANTAGES OF NANO-RAM Permanently nonvolatile High speed similar to DRAM/SRAM High density similar to DRAM Unlimited lifetime Low power consumption Data storage CMOS-compatible manufacturing process Page 20

21 APPLICATIONS AND LIMITATIONS APPLICATIONS: Computer and Laptops (Enabling instant on performance, with no for boot up) Mobile devices (Faster storage of more data for PDA s and handhelds) Embedded memory (More powerful microprocessor, microcontroller, other logic device) High speed network serve Faster and Denser LIMITATIONS: Over supply of DRAM Is relatively costly NRAM is still in research phase Page 21

22 CONCLUSION This paper gives an over-view of application of nanotechnology in field of electronics. Moore s law has held true for almost 40 years now, but the current lithographic technology has physical limits when it comes to making things smaller and the semiconductor industry which often refers to the collection of these as the red brick wall thinks that the wall will be hit in around fifteen years. At the point a new technology will have to take over and nanotechnology offers a variety of potentially viable options and carbon nanotube are one of the most commonly mentioned building blocks of nanotechnology.we could say that the prospects of nanotechnology are very bright.nanotechnology will be an undeniable force in near future. Beginning &usage of NRAM will give rise to instant ON computers. Nonvolatile memories will enable instant booting of computers. Large memories can be building with nanotube technology. Nonvolatile memories offer much better performance combined with data storage when the power is turned OFF. Page 22

23 REFERENCES Carbon Nanotube Based Nonvolatile Random Access Memory for Molecular Computing: Thomas Rueckes, Kyoungha Kim, Ernesto Joselevich, Greg Y. Tseng, Chin-Li Cheung, Charles M. Lieber Nano Engineered Memory solutions-ieee journal Emerging technologies MIT technology review Page 23