29-08-2011, 11:32 AM
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INTRODUCTION
Electronics without silicon is unbelievable, but it will come true with the evolution of Diamond or Carbon chip. Now a day we are using silicon for the manufacturing of Electronic Chip's. It has many disadvantages when it is used in power electronic applications, such as bulk in size, slow operating speed etc. Carbon, Silicon and Germanium are belonging to the same group in the periodic table. They have four valance electrons in their outer shell. Pure Silicon and Germanium are semiconductors in normal temperature. So in the earlier days they are used widely for the manufacturing of electronic components. But later it is found that Germanium has many disadvantages compared to silicon, such as large reverse current, less stability towards temperature etc so in the industry focused in developing electronic components using silicon wafers.
Now research people found that Carbon is more advantages than Silicon. By using carbon as the manufacturing material, we can achieve smaller, faster and stronger chips. They are succeeded in making smaller prototypes of Carbon chip. They invented a major component using carbon that is CARBON NANOTUBE, which is widely used in most modern microprocessors and it will be a major component in the coming era.
Crystalline diamond film that could produce more resilient semiconductor chips than those made from silicon. Until now, synthetic diamonds have proved a poor semiconducting material. Their microscopic crystals are a disorderly hodgepodge, and their edges are not evenly aligned, impeding the flow of current. Now, Schreck and his colleagues have discovered that by growing the diamond film on a surface of iridium, instead of on silicon, they can keep its grain boundaries aligned. Adding atoms of boron or nitrogen enables the diamond film to conduct electricity. Manufacturers plan to build a diamond chip that can withstand temperatures of 500 C, compared to only about 150 C for silicon chips. The chips would be most useful in devices located near hot-burning engines, such as those used in automobiles or airplanes
WHAT IS DIAMOND CHIP?
In single definition, Diamond Chip or carbon Chip is an electronic chip manufactured on a Diamond structural Carbon wafer. OR it can be also defined as the electronic component manufactured using carbon as the wafer. The major component using carbon is (CNT) Carbon Nanotube. Carbon Nanotube is a nano dimensional made by using carbon. It has many unique properties.
HOW IS IT POSSIBLE?
Pure Diamond structural carbon is non-conducting in nature. In order to make it conducting we have to perform doping process. We are using Boron as the p-type doping Agent and the Nitrogen as the n-type doping agent. The doping process is similar to that in the case of Silicon chip manufacturing. But this process will take more time compared with that of silicon because it is very difficult to diffuse through strongly bonded diamond structure. CNT (Carbon Nanotube) is already a semi conductor.
A crystalline diamond film that could produce more resilient semiconductor chips than those made from silicon, commonly synthetic diamonds have proved a poor semi conducting material. Their microscopic crystals are a disorderly hodgepodge, and their edges are not evenly aligned, impeding the flow of current. Now but by growing the diamond film on a surface of iridium, instead of on silicon, they can keep its grain boundaries aligned. Adding atoms of boron or nitrogen enables the diamond film to conduct electricity. Manufacturers plan to build a diamond chip that can withstand temperatures of 500 C, compared to only about 150 C for silicon chips. The chips would be most useful in devices located near hot-burning engines, such as those used in automobiles or airplanes.
Diamond has an extremely high thermal conductivity, can withstand high electric fields, and can be made into a semiconductor -- ideal for power devices.
A diamond semiconductor that operates on the 81 GHz frequency, which is more than twice the speed of earlier devices, has been developed by the Nippon Telegraph and Telephone Corp. (NTT).According to NTT, this latest development will allow amplification in the millimeter-wave band from 30 to 300 GHz possible for the first time.
Diamond chips can work at a much higher frequency or faster speed and be placed in a high-temperature environment, such as a vehicle's engine. Diamond can also resist voltages up to around 200 volts, compared to around 20 volts for a silicon chip. This means power electronics, such as an inverter, can become much smaller in size. At present, a large number of silicon chips are used together to handle high voltages which makes devices large
However, diamond chips are not expected to completely replace silicon chips for another 20 years because of two major bottlenecks. Artificial diamond for chips is still much more expensive than silicon. A four-millimeter-square diamond substrate costs several tens of thousands of yen compared to virtually nothing for silicon, another problem is that electricity cannot travel smoothly through diamond. Thus, researches are seeking impurities that can be added to aid electricity flow.
CARBON NANOTUBE
Carbon nanotubes (CNTs):- are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 28,000,000:1, 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. Their final usage, however, may be limited by their potential toxicity and controlling their property changes in response to chemical treatment.
Nanotubes are members of the fullerene structural family, which also includes the spherical buckyballs. The ends of a nanotube might be capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to several millimeters in length (as of 2008). Nanotubes are categorized assingle-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).
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 sp2 bonds, similar to those of graphite. This bonding structure, which is stronger than the sp3 bonds found in diamonds, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces.
Types of carbon nanotubes and related structures
Single-walled
Most single-walled nanotubes (SWNT) have a diameter of close to 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder. The way the graphene sheet is wrapped is represented by a pair of indices (n,m) called the chiral vector. The integers n and m denote the number of unit vectors along two directions in the honeycomb crystal lattice of graphene. If m = 0, the nanotubes are called "zigzag". If n = m, the nanotubes are called "armchair". Otherwise, they are called "chiral".
Single-walled nanotubes are an important variety of carbon nanotube because they exhibit electric properties that are not shared by the multi-walled carbon nanotube (MWNT) variants. Single-walled nanotubes are the most likely candidate for miniaturizing electronics beyond the micro electromechanical scale currently used in electronics. The most basic building block of these systems is the electric wire, and SWNTs can be excellent conductors. One useful application of SWNTs is in the development of the first intramolecular field effect transistors (FET). Production of the first intramolecular logic gate using SWNT FETs has recently become possible as well. To create a logic gate you must have both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to protect half of an SWNT from oxygen exposure, while exposing the other half to oxygen. This results in a single SWNT that acts as a NOT logic gate with both p and n-type FETs within the same molecule.
Single-walled nanotubes are still very expensive to produce, around $1500 per gram as of 2000, and the development of more affordable synthesis techniques is vital to the future of carbon nanotechnology. If cheaper means of synthesis cannot be discovered, it would make it financially impossible to apply this technology to commercial-scale applications. Several suppliers offer as-produced arc discharge SWNTs for ~$50–100 per gram as of 2007.
Multi-walled
Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite. There are two models which can be used to describe the structures of multi-walled nanotubes. In the Russian Doll model, sheets of graphite are arranged in concentric cylinders, e.g. a (0,8) single-walled nanotube (SWNT) within a larger (0,10) single-walled nanotube. In the Parchment model, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper. The interlayer distance in multi-walled nanotubes is close to the distance between graphene layers in graphite, approximately 3.4 Å.
The special place of double-walled carbon nanotubes (DWNT) must be emphasized here because their morphology and properties are similar to SWNT but their resistance to chemicals is significantly improved. This is especially important when functionalization is required (this means grafting of chemical functions at the surface of the nanotubes) to add new properties to the CNT. In the case of SWNT, covalent functionalization will break some C=C double bonds, leaving "holes" in the structure on the nanotube and thus modifying both its mechanical and electrical properties. In the case of DWNT, only the outer wall is modified. DWNT synthesis on the gram-scale was first proposed in 2003 by the CCVD technique, from the selective reduction of oxide solutions in methane and hydrogen.
Torus
A nanotorus is theoretically described as carbon nanotube bent into a torus (doughnut shape). Nanotori are predicted to have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii. Properties such as magnetic moment, thermal stability etc. vary widely depending on radius of the torus and radius of the tube.
INTRODUCTION
Electronics without silicon is unbelievable, but it will come true with the evolution of Diamond or Carbon chip. Now a day we are using silicon for the manufacturing of Electronic Chip's. It has many disadvantages when it is used in power electronic applications, such as bulk in size, slow operating speed etc. Carbon, Silicon and Germanium are belonging to the same group in the periodic table. They have four valance electrons in their outer shell. Pure Silicon and Germanium are semiconductors in normal temperature. So in the earlier days they are used widely for the manufacturing of electronic components. But later it is found that Germanium has many disadvantages compared to silicon, such as large reverse current, less stability towards temperature etc so in the industry focused in developing electronic components using silicon wafers.
Now research people found that Carbon is more advantages than Silicon. By using carbon as the manufacturing material, we can achieve smaller, faster and stronger chips. They are succeeded in making smaller prototypes of Carbon chip. They invented a major component using carbon that is CARBON NANOTUBE, which is widely used in most modern microprocessors and it will be a major component in the coming era.
Crystalline diamond film that could produce more resilient semiconductor chips than those made from silicon. Until now, synthetic diamonds have proved a poor semiconducting material. Their microscopic crystals are a disorderly hodgepodge, and their edges are not evenly aligned, impeding the flow of current. Now, Schreck and his colleagues have discovered that by growing the diamond film on a surface of iridium, instead of on silicon, they can keep its grain boundaries aligned. Adding atoms of boron or nitrogen enables the diamond film to conduct electricity. Manufacturers plan to build a diamond chip that can withstand temperatures of 500 C, compared to only about 150 C for silicon chips. The chips would be most useful in devices located near hot-burning engines, such as those used in automobiles or airplanes
WHAT IS DIAMOND CHIP?
In single definition, Diamond Chip or carbon Chip is an electronic chip manufactured on a Diamond structural Carbon wafer. OR it can be also defined as the electronic component manufactured using carbon as the wafer. The major component using carbon is (CNT) Carbon Nanotube. Carbon Nanotube is a nano dimensional made by using carbon. It has many unique properties.
HOW IS IT POSSIBLE?
Pure Diamond structural carbon is non-conducting in nature. In order to make it conducting we have to perform doping process. We are using Boron as the p-type doping Agent and the Nitrogen as the n-type doping agent. The doping process is similar to that in the case of Silicon chip manufacturing. But this process will take more time compared with that of silicon because it is very difficult to diffuse through strongly bonded diamond structure. CNT (Carbon Nanotube) is already a semi conductor.
A crystalline diamond film that could produce more resilient semiconductor chips than those made from silicon, commonly synthetic diamonds have proved a poor semi conducting material. Their microscopic crystals are a disorderly hodgepodge, and their edges are not evenly aligned, impeding the flow of current. Now but by growing the diamond film on a surface of iridium, instead of on silicon, they can keep its grain boundaries aligned. Adding atoms of boron or nitrogen enables the diamond film to conduct electricity. Manufacturers plan to build a diamond chip that can withstand temperatures of 500 C, compared to only about 150 C for silicon chips. The chips would be most useful in devices located near hot-burning engines, such as those used in automobiles or airplanes.
Diamond has an extremely high thermal conductivity, can withstand high electric fields, and can be made into a semiconductor -- ideal for power devices.
A diamond semiconductor that operates on the 81 GHz frequency, which is more than twice the speed of earlier devices, has been developed by the Nippon Telegraph and Telephone Corp. (NTT).According to NTT, this latest development will allow amplification in the millimeter-wave band from 30 to 300 GHz possible for the first time.
Diamond chips can work at a much higher frequency or faster speed and be placed in a high-temperature environment, such as a vehicle's engine. Diamond can also resist voltages up to around 200 volts, compared to around 20 volts for a silicon chip. This means power electronics, such as an inverter, can become much smaller in size. At present, a large number of silicon chips are used together to handle high voltages which makes devices large
However, diamond chips are not expected to completely replace silicon chips for another 20 years because of two major bottlenecks. Artificial diamond for chips is still much more expensive than silicon. A four-millimeter-square diamond substrate costs several tens of thousands of yen compared to virtually nothing for silicon, another problem is that electricity cannot travel smoothly through diamond. Thus, researches are seeking impurities that can be added to aid electricity flow.
CARBON NANOTUBE
Carbon nanotubes (CNTs):- are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 28,000,000:1, 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. Their final usage, however, may be limited by their potential toxicity and controlling their property changes in response to chemical treatment.
Nanotubes are members of the fullerene structural family, which also includes the spherical buckyballs. The ends of a nanotube might be capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to several millimeters in length (as of 2008). Nanotubes are categorized assingle-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).
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 sp2 bonds, similar to those of graphite. This bonding structure, which is stronger than the sp3 bonds found in diamonds, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces.
Types of carbon nanotubes and related structures
Single-walled
Most single-walled nanotubes (SWNT) have a diameter of close to 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder. The way the graphene sheet is wrapped is represented by a pair of indices (n,m) called the chiral vector. The integers n and m denote the number of unit vectors along two directions in the honeycomb crystal lattice of graphene. If m = 0, the nanotubes are called "zigzag". If n = m, the nanotubes are called "armchair". Otherwise, they are called "chiral".
Single-walled nanotubes are an important variety of carbon nanotube because they exhibit electric properties that are not shared by the multi-walled carbon nanotube (MWNT) variants. Single-walled nanotubes are the most likely candidate for miniaturizing electronics beyond the micro electromechanical scale currently used in electronics. The most basic building block of these systems is the electric wire, and SWNTs can be excellent conductors. One useful application of SWNTs is in the development of the first intramolecular field effect transistors (FET). Production of the first intramolecular logic gate using SWNT FETs has recently become possible as well. To create a logic gate you must have both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to protect half of an SWNT from oxygen exposure, while exposing the other half to oxygen. This results in a single SWNT that acts as a NOT logic gate with both p and n-type FETs within the same molecule.
Single-walled nanotubes are still very expensive to produce, around $1500 per gram as of 2000, and the development of more affordable synthesis techniques is vital to the future of carbon nanotechnology. If cheaper means of synthesis cannot be discovered, it would make it financially impossible to apply this technology to commercial-scale applications. Several suppliers offer as-produced arc discharge SWNTs for ~$50–100 per gram as of 2007.
Multi-walled
Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite. There are two models which can be used to describe the structures of multi-walled nanotubes. In the Russian Doll model, sheets of graphite are arranged in concentric cylinders, e.g. a (0,8) single-walled nanotube (SWNT) within a larger (0,10) single-walled nanotube. In the Parchment model, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper. The interlayer distance in multi-walled nanotubes is close to the distance between graphene layers in graphite, approximately 3.4 Å.
The special place of double-walled carbon nanotubes (DWNT) must be emphasized here because their morphology and properties are similar to SWNT but their resistance to chemicals is significantly improved. This is especially important when functionalization is required (this means grafting of chemical functions at the surface of the nanotubes) to add new properties to the CNT. In the case of SWNT, covalent functionalization will break some C=C double bonds, leaving "holes" in the structure on the nanotube and thus modifying both its mechanical and electrical properties. In the case of DWNT, only the outer wall is modified. DWNT synthesis on the gram-scale was first proposed in 2003 by the CCVD technique, from the selective reduction of oxide solutions in methane and hydrogen.
Torus
A nanotorus is theoretically described as carbon nanotube bent into a torus (doughnut shape). Nanotori are predicted to have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii. Properties such as magnetic moment, thermal stability etc. vary widely depending on radius of the torus and radius of the tube.
