(p109)
"When CNTs first burst onto the technology scene in 1991 after a paper published in the journal Nature by Sumio Iijima the future looked so bright that materials scientists just had to wear shades. CNTs were expected to transform the electronics industry through the production of transistors that were much smaller, faster and more efficient than anything that could be achieved with silicon chip technology.
It hasn't worked out that way because there were a number of unforeseen problems in producing CNT-based electronics on an industrial scale. Now, however, those problems are being solved and the CNT revolution promised 25 years ago may be on the horizon."
"The type of CNT that is of interest in the electronics industry is a single-walled tube made from a carbon lattice that is one carbon atom thick. The tube has a diameter of 1 nanometer (nm) which is about 1/10,000th the diameter of a human hair."
"Carbon and silicon are both semiconductors. However, because of their small size, the number of transistors made from CNTs that can be placed on a chip is much greater than the number (currently in the single-digit billions) that can be placed on a silicon chip. CNT chips are not only smaller, they're faster, more efficient and they generate much less heat than silicon chips. In other words, CNT chips would give you lightening speed and much longer battery life without overheating and the need for fans to dissipate excess heat."
"Theoretically, integrated circuits made from CNTS are a vast improvement over silicon. Practically, there are three problems that have made it difficult to produce CNTs for electronics at an industrial scale.
"While it has long been appreciated that semiconducting single-wall carbon nanotubes (CNTs) have all the required electrical, thermal, mechanical and chemical properties to be an ideal electronic material for next generation electronic devices, it has taken 15 years from the first reports on CNT field-effect transistors (FETs) to the appearance of the first CNT computer. The motivation behind the development of CNT electronics is the realization that the Si-based complementary metal–oxide–semiconductor (CMOS) technology will reach absolute limits on its performance by around 2020 , and improvements on transistor speed and performance will have to come from new materials rather than from scaling silicon further."
"CNT technology is predicted to be able to outperform silicon-based CMOS technologies by several technology generations and is the most promising CMOS technology that can be scaled down to 5 nm:"
"A classic FET is a three terminal device which includes such key components as the source (S), drain (D) and gate (G) electrodes; a channel between the source and drain; and a dielectric (typically oxide) separating the gate from the channel."
https://spectrum.ieee.org/semiconductors/devices/how-well-put-a-carbon-nanotube-computer-in-your-hand
"A carbon-nanotube field-effect transistor (FET) resembles a conventional silicon FET. The main difference is the current-carrying channel, which is made from carbon nanotubes [yellow] instead of silicon."
108EN Carbon nanotube (CNT) electronics
https://www.forbes.com/sites/kevinmurnane/2016/09/08/carbon-nanotubes-are-getting-closer-to-making-our-electronic-devices-obsolete/#5e7b9dec33d6"When CNTs first burst onto the technology scene in 1991 after a paper published in the journal Nature by Sumio Iijima the future looked so bright that materials scientists just had to wear shades. CNTs were expected to transform the electronics industry through the production of transistors that were much smaller, faster and more efficient than anything that could be achieved with silicon chip technology.
It hasn't worked out that way because there were a number of unforeseen problems in producing CNT-based electronics on an industrial scale. Now, however, those problems are being solved and the CNT revolution promised 25 years ago may be on the horizon."
"The type of CNT that is of interest in the electronics industry is a single-walled tube made from a carbon lattice that is one carbon atom thick. The tube has a diameter of 1 nanometer (nm) which is about 1/10,000th the diameter of a human hair."
"Carbon and silicon are both semiconductors. However, because of their small size, the number of transistors made from CNTs that can be placed on a chip is much greater than the number (currently in the single-digit billions) that can be placed on a silicon chip. CNT chips are not only smaller, they're faster, more efficient and they generate much less heat than silicon chips. In other words, CNT chips would give you lightening speed and much longer battery life without overheating and the need for fans to dissipate excess heat."
"Theoretically, integrated circuits made from CNTS are a vast improvement over silicon. Practically, there are three problems that have made it difficult to produce CNTs for electronics at an industrial scale.
- The mixture problem. There are two types of CNTs that are intermixed when the nanotubes are created. One type is a semiconductor which is what you need for creating integrated circuits. The other type, which is metallic, conducts electricity like a wire and markedly degrades or destroys an integrated circuit's performance. Reliable integrated circuits made from CNTs demand nanotubes that are 100% semiconductors. The problem has been finding a way to separate the metallic CNTs from the semiconductors.
- The electrical resistance problem. Conducting electricity through the connection between the nanotube and the metallic components of an integrated circuit is difficult because electrical resistance increases as the size of the connection decreases.
- The alignment problem. Today's state-of-the-art computer chips have over seven billion (mrd) transistors on 14 nanometer chips. Switching from silicon to CNTs allows many more transistors to be placed in the same space. Fitting billions (mrds) of transistors on a minuscule surface demands precise alignment and spacing of the nanotubes. The problem has been finding ways to reliably achieve this precision layout."
"While it has long been appreciated that semiconducting single-wall carbon nanotubes (CNTs) have all the required electrical, thermal, mechanical and chemical properties to be an ideal electronic material for next generation electronic devices, it has taken 15 years from the first reports on CNT field-effect transistors (FETs) to the appearance of the first CNT computer. The motivation behind the development of CNT electronics is the realization that the Si-based complementary metal–oxide–semiconductor (CMOS) technology will reach absolute limits on its performance by around 2020 , and improvements on transistor speed and performance will have to come from new materials rather than from scaling silicon further."
"CNT technology is predicted to be able to outperform silicon-based CMOS technologies by several technology generations and is the most promising CMOS technology that can be scaled down to 5 nm:"
"A classic FET is a three terminal device which includes such key components as the source (S), drain (D) and gate (G) electrodes; a channel between the source and drain; and a dielectric (typically oxide) separating the gate from the channel."
https://spectrum.ieee.org/semiconductors/devices/how-well-put-a-carbon-nanotube-computer-in-your-hand
"A carbon-nanotube field-effect transistor (FET) resembles a conventional silicon FET. The main difference is the current-carrying channel, which is made from carbon nanotubes [yellow] instead of silicon."
