Entries with tag carbon nanotubes.

Scientists Create Sensitive Electronic Whiskers

Researchers from the US Lawrence Berkeley National Laboratory and the University of California, Berkeley, scientists have developed extremely sensitive sensors inspired by animal whiskers. These tactile sensors, sensitive to even very light pressure, consist of composite carbon-nanotube films and silver nanoparticles applied to fibers. The researchers explain the sensitivity is a product of using elastic fibers that respond to even the slightest amount of pressure. The scientists say the whiskers’ sensitivity and electrical can be tuned by changing the ratio of the components used. Mammals and insects use their hairlike whiskers as sensors for monitoring wind and for navigation. The researchers’ sensors were able to accurately complete 2D and 3D wind-flow mapping. They say their whiskers could also be used for spatial mapping as well as in sensors that measure wearers’ heartbeat and pulse rate. The scientists published their work in the Proceedings of the National Academy of Sciences. (National Monitor)(University of California Berkeley Research)(Proceedings of the National Academy of Sciences)
 

Stanford Researchers Build First Carbon-Nanotube Computer

Stanford University researchers have created the first working computer built exclusively using carbon-nanotube transistors. The computer can run a basic operating system, perform calculations, and switch between multiple processes running at the same time. The announcement is significant because researchers are looking for ways to replace silicon in transistors in order to create faster processors and higher-performing computers. The first nanotube transistor was developed in 1998. Researchers worldwide have been working to overcome problems inherent in growing carbon nanotubes and ensuring that the resulting device has no flaws that would impede its use. The Stanford researchers made the system on a single wafer with 197 dies. Each die contains five nanotube computers. Each computer consists of 178 carbon nanotube transistors. The device was made with standard chip-fabrication techniques and design tools, which would make the systems suitable for production in conventional facilities. Stanford professor Philip Wong said the system is a rudimentary first step in developing this type of computer. They published their research in Nature. (The Wall Street Journal)(Stanford News Service)(Nature -- 1) (Nature -- 2) 

New Fabrication Method Creates Large, Affordable Flexible Displays

A new method for printing large areas of carbon nanotube thin-film transistors on plastic surfaces would enable the creation of flexible displays and sensor networks. Researchers, led by Ali Javey, professor of electrical engineering and computer science at the University of California, Berkeley, used a conventional printing technology known as gravure printing to make uniform arrays of high-performing transistors from carbon nanotubes on flexible plastic sheets. This is the first time fully printed carbon nanotubes that are also high performance have been demonstrated. They report that their method creates transistor arrays with higher mobility than other, prior carbon nanotube printing technologies. Electron mobility is critical in display technologies. It translates into needing less current for OLEDs, for example. Researchers say the process could lead to  manufacturing large-area, low-power sensor arrays and displays using roll-to-roll printing and are now working on refining their method in hopes of printing more complex circuits. They published their findings in NanoLetters. (Technology Review)(NanoLetters)
 

Stanford Team Demonstrates Nanotube Chip

Stanford University researchers have demonstrated a computer chip consisting of carbon nanotube-based transistors. The team—led by professor Philip Wong—created the chip with semiconducting carbon nanotubes. The resulting device is highly conductive and can be significantly smaller than silicon-based devices, which is increasingly important as device sizes continue to shrink. However, growing nanotubes with semiconducting properties is challenging. Today, most methods create batches of nanotubes in which as many as 30 percent are metallic rather than semiconducting. To address this, the scientists grouped the nanotubes in a way that self-corrects errors, allowing the device to continue working despite flawed materials. Rather than explain this process, they built a chip for analog-to-digital conversion using the carbon nanotube circuit. The scientists next plan to determine whether their technology could scale enough for use as a CPU in conventional computers. They demonstrated their technology at the recent IEEE International Solid-State Circuits Conference in San Francisco.(PhysOrg)(Technology Review) 

New Technology Builds Sensors by Drawing

Carbon nanotubes have proven to be a promising technology for use in detecting leaks of harmful gasses, constructing sensors made with the material is typically a challenging, hazardous process ill-suited for large-scale production. MIT researchers have developed a pencil lead made from stable, compressed carbon nanotubes that can be used with a regular mechanical pencil to draw sensors on any paper surface. The pencil is used on a sheet of paper imprinted with tiny gold electrodes. An electrical current is applied and, if the current changes any, this means gas present in the environment has bound to the carbon nanotubes. The researchers developed a sensor to detect small amounts of ammonia gas. The researchers say they can add metal atoms to the nanotube walls or wrapping various materials around the tubes to enable the sensors to detect a wide range of gases. The researchers published their work in the journal Angewandte Chemie.
(EurekAlert)(MIT News Office)(Angewandte Chemie)
Carbon nanotubes have proven to be a promising technology for use in detecting leaks of harmful gasses, constructing sensors made with the material is typically a challenging, hazardous process ill-suited for large-scale production. MIT researchers have developed a pencil lead made from stable, compressed carbon nanotubes that can be used with a regular mechanical pencil to draw sensors on any paper surface. The pencil is used on a sheet of paper imprinted with tiny gold electrodes. An electrical current is applied and, if the current changes any, this means gas present in the environment has bound to the carbon nanotubes. The researchers developed a sensor to detect small amounts of ammonia gas. The researchers say they can add metal atoms to the nanotube walls or wrapping various materials around the tubes to enable the sensors to detect a wide range of gases. The researchers published their work in the journal Angewandte Chemie.
(EurekAlert)(MIT News Office)(Angewandte Chemie)

Carbon nanotubes have proven to be a promising technology for use in detecting leaks of harmful gasses, constructing sensors made with the material is typically a challenging, hazardous process ill-suited for large-scale production. MIT researchers have developed a pencil lead made from stable, compressed carbon nanotubes that can be used with a regular mechanical pencil to draw sensors on any paper surface. The pencil is used on a sheet of paper imprinted with tiny gold electrodes. An electrical current is applied and, if the current changes any, this means gas present in the environment has bound to the carbon nanotubes. The researchers developed a sensor to detect small amounts of ammonia gas. The researchers say they can add metal atoms to the nanotube walls or wrapping various materials around the tubes to enable the sensors to detect a wide range of gases. The researchers published their work in the journal Angewandte Chemie. (EurekAlert)(MIT News Office)(Angewandte Chemie)

 

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