Any Digital Camera Can Take Multibillion-pixel Shots With New Device

Source:

http://www.sciencedaily.com/releases/2007/09/070926111630.htm

Science Daily — Researchers at Carnegie Mellon University, in collaboration with scientists at NASA's Ames Research Center, have built a low-cost robotic device that enables any digital camera to produce breathtaking gigapixel (billions of pixels) panoramas, called GigaPans.

The technology gives people a new way to make and share images of their environment. It is being used by students to document their communities and by the Commonwealth of Pennsylvania to make Civil War sites accessible on the Web. To promote further sharing of this imagery, Carnegie Mellon has launched a public Web site, http://www.gigapan.org/, where people can upload and interactively explore panoramic images of any format.
In cooperation with Google, researchers also have created a GigaPan layer on Google Earth. Anyone using Google Earth can now fly into these GigaPan panoramas in the context of exploring the world.
Researchers have begun a public beta process with the GigaPan hardware, Web site, and software. The hardware technology enabling GigaPan images is a robotic camera mount, jointly designed and manufactured by Charmed Labs of Austin Texas. The tripod-like mount makes it possible for a digital camera to take hundreds of overlapping images of landscapes, buildings or rooms. Then, using software developed by Carnegie Mellon and Ames, these images can be arranged in a grid and digitally stitched together into a single image that could consist of tens of billions of pixels.
These huge image files can then be explored by zooming in on features of interest in a manner similar to Google Earth. "We have taken imagery and made it a new tool for exploration and for enhancing global understanding," said Illah Nourbakhsh, associate professor in the School of Computer Science's Robotics Institute. Nourbakhsh and Randy Sargent, senior systems scientist at Carnegie Mellon West in Moffett Field, Calif., led GigaPan's development. "An ordinary photo makes it possible to cross language barriers," Nourbakhsh explained. "But a GigaPan provides so much information that it leads to conversations between the person who took the panoramas and the people who are exploring it and discovering new details."
Last spring, the Pennsylvania Board of Tourism began to use GigaPan to enable people to virtually explore Civil War sites. The technology is also being used for Robot250, an arts-based robotics program in the Pittsburgh area. Robot250 will increase technical literacy by teaching students, artists and other members of the public how to build customized robots.
Nourbakhsh and his colleagues recently began to work with UNESCO's International Bureau of Education and its Associated Schools Network on a project that will link school children in different parts of the world in exploring issues of cultural identity through a classroom project. Middle school children from Pittsburgh to South Africa to Trinidad and Tobago will use the GigaPan camera to share images of their neighborhoods, lives and cultures. "This project will explore curriculum development from the local to the global level," said IBE Director Clementina Acedo.
"It is an extraordinary opportunity to link a school-community based educational practice with high-end technology in the service of children's innovative learning, personal development and world communication. Plans call for the experiences of these children from poorer and richer countries to be presented at the 48th session of the International Conference of Education scheduled to take place in Geneva in November 2008.
Besides being a tool for education, Nourbakhsh and Sargent see the GigaPan system as an important tool for ecologists, biologists and other scientists. They plan to foster this effort by making several dozen GigaPans available to leading scientists with support from the Fine Foundation of Pittsburgh.
Nourbakhsh hopes the non-commercial GigaPan site will help to develop a community of GigaPan producers and users. "We're not interested in becoming just another photo-sharing site," he said. "We want as many people as possible involved. GigaPan is not just about the vision of the person who makes the image. People who explore the image can make discoveries and gain insights in ways that may be just as important."
Sargent got the idea for GigaPan when he was a technical staff member at Ames Research Center, helping to develop software for combining images from NASA's Mars Exploration Rovers into panoramas. He became convinced that the same technology could open people's eyes to the diversity of their own planet. "It is increasingly important to give people a broad view of the world, particularly to help us understand different cultures and different environments," he said. "It's too easy to have blinders on and to only see and understand what is local."
The GigaPan camera system is part of a larger effort known as the Global Connection Project, led by Nourbakhsh and Sargent. Its purpose is to make people all over the world more aware of their neighbors.
Note: This story has been adapted from material provided by Carnegie Mellon University.

Fausto Intilla

www.oloscience.com

Quantum Device Traps, Detects And Manipulates The Spin Of Single Electrons

Source:

http://www.sciencedaily.com/releases/2007/09/070927135543.htm

Science Daily — A novel device, developed by a team led by University at Buffalo engineers, simply and conveniently traps, detects and manipulates the single spin of an electron, overcoming some major obstacles that have prevented progress toward spintronics and spin-based quantum computing.

Published online recently in Physical Review Letters, the research paper brings closer to reality electronic devices based on the use of single spins and their promise of low-power/high-performance computing.
"The task of manipulating the spin of single electrons is a hugely daunting technological challenge that has the potential, if overcome, to open up new paradigms of nanoelectronics," said Jonathan P. Bird, Ph.D., professor of electrical engineering in the UB School of Engineering and Applied Sciences and principal investigator on the project. "In this paper, we demonstrate a novel approach that allows us to easily trap, manipulate and detect single-electron spins, in a scheme that has the potential to be scaled up in the future into dense, integrated circuits."
While several groups have recently reported the trapping of a single spin, they all have done so using quantum dots, nanoscale semiconductors that can only demonstrate spin trapping in extremely cold temperatures, below 1 degree Kelvin.
The cooling of devices or computers to that temperature is not routinely achievable, Bird said, and it makes systems far more sensitive to interference.
The UB group, by contrast, has trapped and detected spin at temperatures of about 20 degrees Kelvin, a level that Bird says should allow for the development of a viable technology, based on this approach.
In addition, the system they developed requires relatively few logic gates, the components in semiconductors that control electron flow, making scalability to complex integrated circuits very feasible.
The UB researchers achieved success through their innovative use of quantum point contacts: narrow, nanoscale constrictions that control the flow of electrical charge between two conducting regions of a semiconductor.
"It was recently predicted that it should be possible to use these constrictions to trap single spins," said Bird. "In this paper, we provide evidence that such trapping can, indeed, be achieved with quantum point contacts and that it may also be manipulated electrically."
The system they developed steers the electrical current in a semiconductor by selectively applying voltage to metallic gates that are fabricated on its surface.
These gates have a nanoscale gap between them, Bird explained, and it is in this gap where the quantum point contact forms when voltage is applied to them.
By varying the voltage applied to the gates, the width of this constriction can be squeezed continuously, until it eventually closes completely, he said.
"As we increase the charge on the gates, this begins to close that gap," explained Bird, "allowing fewer and fewer electrons to pass through until eventually they all stop going through. As we squeeze off the channel, just before the gap closes completely, we can detect the trapping of the last electron in the channel and its spin."
The trapping of spin in that instant is detected as a change in the electrical current flowing through the other half of the device, he explained.
"One region of the device is sensitive to what happens in the other region," he said.
Now that the UB researchers have trapped and detected single spin, the next step is to work on trapping and detecting two or more spins that can communicate with each other, a prerequisite for spintronics and quantum computing.
Co-authors on the paper are Youngsoo Yoon, Ph.D., a UB doctoral student in electrical engineering; L. Mourokh of Queens College and the College of Staten Island of the City University of New York; T. Morimoto, N. Aoki and Y. Ochiai of Chiba University in Japan; and J. L. Reno of Sandia National Laboratories.
The research was funded by the U.S. Department of Energy. Bird, who also has received funding from the UB Office of the Vice President for Research, was recruited to UB with a faculty recruitment grant from the New York State Office of Science, Technology and Academic Outreach (NYSTAR).
Note: This story has been adapted from material provided by University at Buffalo.

Fausto Intilla

www.oloscience.com

Nanowire Generates Power By Harvesting Energy From The Environment

Source:

http://www.sciencedaily.com/releases/2007/09/070927121113.htm

Science Daily — As the sizes of sensor networks and mobile devices shrink toward the microscale, and even nanoscale, there is a growing need for suitable power sources. Because even the tiniest battery is too big to be used in nanoscale devices, scientists are exploring nanosize systems that can salvage energy from the environment.

Now, researchers at the University of Illinois have shown that a single nanowire can produce power by harvesting mechanical energy. Made of piezoelectric material, the nanowire generates a voltage when mechanically deformed. To measure the voltage produced by such a tiny wire, however, the researchers first had to build an extremely sensitive and precise mechanical testing stage.
"With the development of this precision testing apparatus, we successfully demonstrated the first controlled measurement of voltage generation from an individual nanowire," said Min-Feng Yu, a professor of mechanical science and engineering, and a researcher at the university's Beckman Institute. "The new testing apparatus makes possible other difficult, but important, measurements, as well."
Yu and graduate students Zhaoyu Wang, Jie Hu, Abhijit Suryavanshi and Kyungsuk Yum describe the measurement, and the measurement device, in a paper accepted for publication in the journal Nano Letters, and posted on the journal's website.
The nanowire was synthesized in the form of a single crystal of barium titanate, an oxide of barium and titanium used as a piezoelectric material in microphones and transducers, and was approximately 280 nanometers in diameter and 15 microns long.
The precision tensile mechanical testing stage is a finger-size device consisting of two coplanar platforms -- one movable and one stationary -- separated by a 3-micron gap. The movable platform is driven by a single-axis piezoelectric flexure stage with a displacement resolution better than 1 nanometer.
When the researchers' piezoelectric nanowire was placed across the gap and fastened to the two platforms, the movable platform induced mechanical vibrations in the nanowire. The voltage generated by the nanowire was recorded by high-sensitivity, charge-sensing electronics.
"The electrical energy produced by the nanowire for each vibrational cycle was 0.3 attojoules (less than one quintillionth of a joule)," Yu said. "Accurate measurements this small could not be made on nanowires before."
While the researchers created mechanical deformations in the nanowire through vibrations caused by external motion, other vibrations in the environment, such as sound waves, should also induce deformations. The researchers' next step is to accurately measure the piezoelectric nanowire's response to those acoustic vibrations.
"In addition, because of the fine precision offered by the mechanical testing stage, it should also be possible to quantitatively compare the intrinsic properties of the nanowire to those of the bulk material," Yu said. "This will allow us to study the scale effect related to electromechanical coupling in nanoscale systems."
Funding was provided by the National Science Foundation. Part of the work was carried out in the University's Center for Microanalysis of Materials, which is partially supported by the U.S. Department of Energy.
Note: This story has been adapted from a news release issued by University of Illinois at Urbana-Champaign.

Fausto Intilla

www.oloscience.com

Robot For Lunar Prospecting Under Development

Source:

http://www.sciencedaily.com/releases/2007/09/070920145347.htm

Science Daily — Researchers in the Robotics Institute of Carnegie Mellon University's School of Computer Science are building a robotic prospector for NASA that can creep over rocky slopes and then anchor itself as a stable platform for drilling deep into extraterrestrial soils.

Called "Scarab," this four-wheeled robot will never leave the Earth. But it will demonstrate technologies that a lunar rover will need to find concentrations of hydrogen, possibly water and other volatile chemicals on the moon that could be mined to produce fuel, water and air that are essential for supporting lunar outposts.
Scarab is equipped with a Canadian-made drill for obtaining meter-long geological core samples and features a novel rocker-arm suspension that enables the robot to plant its belly on the ground for drilling operations.
"A lunar prospector will face a hostile environment in the perpetual darkness of craters at the moon's southern pole, where ground temperatures are minus 385 degrees and no energy source is at hand," said William "Red" Whittaker, the Fredkin Research Professor and principal investigator of the NASA-funded project. "It's a place where humans can't work effectively, but where Scarab will thrive, even while operating on the electrical power required to illuminate a 100-watt light bulb."
Robotic prospecting on the moon poses substantial, sometimes conflicting challenges. Scarab must be agile enough to travel miles over sandy, rock-strewn soil, but also serve as a stable drilling platform. Operating for months in total darkness, it cannot rely on solar energy or batteries for power. Instead it will use a radioisotope source that places a premium on energy efficiency. To navigate in total darkness, Scarab must rely on new, low-power, laser-based sensors.
"As a consequence of the power restrictions, it's not very speedy," said David Wettergreen, associate research professor of robotics and leader of Scarab's software and autonomy development. With a top speed of just four inches per second, Scarab tries the patience of even the most laid-back observer. When faced with particularly large obstacles or drilling tasks, it may pause to store up extra power.
To optimize efficiency, the robot must be as light as possible. But to operate the coring drill, the vehicle also has to be massive enough to apply sufficient downward pressure on the drill and counter the torque of the rotating drill. Researchers estimate it must weigh at least 250 kilograms, or about 550 pounds.
The suspension allows Scarab to make the most of its weight by enabling it to lower its 5 1/2-foot-by-3-foot body to the ground for drilling operations. "One of the design innovations was to put the drill in the center of the robot," Wettergreen said, rather than attaching it to an arm. "Scarab can apply its entire mass onto the drill, so that everything is assisting the drilling operation."
The suspension also makes it possible for Scarab to raise its body as much as 21 inches off the ground, so it can straddle rocks or lean as it negotiates steep slopes.
"It's a good combination vehicle that does two things very well," said John Caruso, project manager at NASA's Glenn Research Center in Cleveland. "Scarab is successful because it achieves the design simplicity of a single-purpose machine while accomplishing the multiple purposes of driving and drilling in darkness."
Also important is that the vehicle has been developed as an integrated package based on the requirements of an entire prospecting mission, Caruso said. NASA hasn't announced such a mission as yet, he noted, but developing the technology now will ultimately lower the technical risk for such an undertaking. Glenn Research Center is developing radioisotope power sources for deep space and lunar applications.
The drill is being built by the Northern Centre For Advanced Technology Inc. in Sudbury, Ontario, and will be capable of processing and analyzing the geologic cores it obtains.
Researchers at NASA's Ames Research Center are collaborating to evaluate navigational sensors and algorithms for operation in darkness, such as a "light striper" being built at Carnegie Mellon that detects obstructions by shining laser beams and then looking for distortions in the beams.
Researchers at the Robotics Institute have been working since March to build the robot and develop its autonomous navigation and scientific software. The carbon-composite body was designed and built by a team of engineers headed by John Thornton, a student who also builds streamlined racers featured in Carnegie Mellon's annual Buggy Races.
Development work continues on software that can use all of Scarab's motions to best advantage and enable it to navigate autonomously in the dark. A field experiment planned for the end of the year will put driving and drilling in the dark together in a complete demonstration of the lunar mission concept.
The project is funded through NASA's Johnson Space Center in Houston and its In-situ Resource Utilization program.
Whittaker has announced that he is assembling a team to compete for the Google Lunar X-Prize and its $20 million grand prize for operating a privately funded robot on the moon by 2012. That effort is separate and distinct from the NASA-funded Scarab project, which is developing technologies that could be used on the moon but are being tested on Earth.
Note: This story has been adapted from a news release issued by Carnegie Mellon University.

Fausto Intilla

www.oloscience.com

Nanomaterials With A Bright Future

Source:

http://www.sciencedaily.com/releases/2007/09/070913185042.htm

Science Daily — An innovative and inexpensive way of making nanomaterials on a large scale has resulted in novel forms of advanced materials that pave the way for exceptional and unexpected optical properties.

The new fabrication technique, known as soft lithography, or SIL, offers many significant advantages over existing techniques, including the ability to scale-up the manufacturing process to produce devices in large quantities.
The optical nanomaterials in this research are called 'plasmonic metamaterials' because their unique physical properties originate from shape and structure rather than material composition only. Two examples of metamaterials in the natural world are peacock feathers and butterfly wings. Their brightly colored patterns are due to structural variations at the hundreds of nanometers level, which cause them to absorb or reflect light.
Through the development of a new nanomanufacturing technique, Odom and her co-workers have succeeded in making gold films with virtually infinite arrays of perforations as small as 100 nanometers--500-1000 times smaller than a human hair. On a magnified scale, these perforated gold films look like Swiss cheese except the perforations are well-ordered and can spread over macroscale distances. The researchers' ability to make these optical metamaterials inexpensively and on large wafers or sheets is what sets this work apart from other techniques.
"One of the biggest problems with nanomaterials has always been their 'scalability,'" Odom said. "It's been very difficult or prohibitively expensive to pattern them over areas larger than about one square millimeter. This research is exciting not only because it demonstrates a new type of patterning technique that is cheap, but also one that can produce very high quality optical materials with interesting properties."
For example, if the perforations or holes are patterned into microscale "patches," they show dramatically different transmission behavior of light compared to an infinite array of holes. The patches appear to focus light while the infinite arrays do not.
Moreover, their optical transmission can be altered simply by changing the geometry of perforations rather than having to "cook" a new composition of materials. This feature makes them very attractive in terms of tuning their behavior to a given need with ease. These materials can also be superior as optical sensors, and they open the possibility of ultra-small sources of light. Furthermore, given their precise organization, they can serve as templates for making their own clones or for making other ordered structures at the nanoscale, such as arrays of nanoparticles.
"The work of Professor Odom is an outcome of a grant mechanism at NSF called Small Grants for Exploratory Research that is aimed at exploring high-risk, high-payoff ideas that are potentially transformative to the field said Harsh Deep Chopra, director of NSF's Metals Program in the Division of Materials Research. "The early results are encouraging and suggest the potential for a new generation of optical devices." This work is supported both the Metals Program and the Materials Research Science and Engineering Centers Program in the Division of Materials Research at NSF.
The research, funded by the National Science Foundation (NSF) and led by Teri Odom of Northwestern University, appears in the September 2007 issue of Nature Nanotechnology.
Note: This story has been adapted from a news release issued by National Science Foundation.

Fausto Intilla

www.oloscience.com

Toward Next-generation Integrated Circuits Made From Carbon Nanotubes

Source:

http://www.sciencedaily.com/releases/2007/09/070917112542.htm

Science Daily — Scientists in Israel are reporting the first simple and inexpensive method for building the large-scale networks of single-walled carbon nanotubes (SWCNT) needed for using these microscopic wisps in a future generation of faster, smaller, and more powerful computers and portable electronic devices.

In a study scheduled for the Sept. 12 issue of ACS' Nano Letters Yael Hanein and colleagues point out that no assembly method has solved all of the key problems involved in fabrication of large networks. Those problems range from aligning SWCNTs in a preset pattern to integrating carbon nanotube circuits into an integrated circuit environment similar to those at the heart of conventional microprocessors.
The study describes a method to manufacture and assemble large arrays of SWCNTs into an integrated circuit format. It can be used on a variety of surfaces and produced on an industrial scale. The process involves creating networks of nanotubes suspended between silicon pillars, which are then transferred onto other surfaces by direct stamping, the researchers say.
Article: "A Complete Scheme for Creating Predefined Networks of Individual Carbon Nanotubes"
Note: This story has been adapted from a news release issued by American Chemical Society.

Fausto Intilla

www.oloscience.com

New Backpack 'Exoskeleton' Lightens The Burden In An Unexpected Way

Source:

http://www.sciencedaily.com/releases/2007/09/070919170025.htm

Science Daily — Researchers in the MIT Media Lab's Biomechatronics Group have created a device to lighten the burden for soldiers and others who carry heavy packs and equipment.
Their invention, known as an exoskeleton, can support much of the weight of a heavy backpack and transfer that weight directly to the ground, effectively taking a load off the back of the person wearing the device.
The researchers report that their prototype can successfully take on 80 percent of an 80-pound load carried on a person's back, but there's one catch: The current model impedes the natural walking gait of the person wearing it.
"You can definitely tell it's affecting your gait," said Conor Walsh, a graduate student who worked on the project, but "you do feel it taking the load off and you definitely feel less stress on your upper body."
The research team was led by Hugh Herr, principal investigator of the Biomechatronics Group and associate professor in the MIT Media Lab. Earlier this summer, Herr and his colleagues unveiled the world's first robotic ankle for lower-limb amputees.
Eventually Herr hopes to create assistive leg devices that can be useful for anyone. Herr said he envisions leg exoskeletons that could help people run without breathing hard, as well as help to carry heavy loads.
"Our dream is that 20 years from now, people won't go to bike racks--they'll go to leg racks," he said.
Exoskeleton devices could boost the weight that a person can carry, lessen the likelihood of leg or back injury and reduce the perceived level of difficulty of carrying a heavy load.
The person wearing the exoskeleton places his or her feet in boots attached to a series of tubes that run up the leg to the backpack, transferring the weight of the backpack to the ground. Springs at the ankle and hip and a damping device at the knee allow the device to approximate the walking motion of a human leg, with a very small external power input (one watt).
Other research teams have produced exoskeleton devices that can successfully carry a load but require a large power source (about 3,000 watts, supplied by a gasoline engine).
When the MIT researchers tested their device, they found that although the load borne by the wearer's back was lightened, the person carrying the load had to consume 10 percent more oxygen than normal, because of the extra effort to compensate for the gait interference.
The team hopes to revise the design so the exoskeleton more closely mimics the movement of a human leg, allowing for more normal walking motion. The most important result of this study, says Walsh, is that the team's spring-based, low-energy design shows promise.
"This is the first time that it has been tested," he said. "We didn't know what to expect."
This research is reported in the September issue of the International Journal of Humanoid Robotics.
The research was funded by the Defense Advanced Research Projects Agency.
Note: This story has been adapted from a news release issued by Massachusetts Institute of Technology.

Fausto Intilla
www.oloscience.com

Novel Method For Nanostructured Polymer Thin Films Developed

Source:

http://www.sciencedaily.com/releases/2007/09/070914105555.htm

Science Daily — All researchers at the National Institute of Standards and Technology (NIST) wanted was a simple, quick method for making thin films of block copolymers or BCPs (chemically distinct polymers linked together) in order to have decent samples for taking measurements important to the microelectronics industry.

What they got for their efforts, as detailed in the Sept. 12, 2007, Nano Letters,* was an unexpected bonus: a unique annealing process that may make practical the use of BCP thin films for patterning nanoscale features in next-generation microchips and data storage devices.
BCP thin films have been highly desired by semiconductor manufacturers as patterns for laying down very fine features on microchips, such as arrays of tightly spaced, nanoscale lines. Annealing certain BCP films--a controlled heating process--causes one of the two polymer components to segregate into regular patterns of nanocylinder lines separated by distances as small as five nanometers or equally regular arrays of nanoscale dots. Chemically removing the other polymer leaves the pattern behind as a template for building structures on the microchip.
In traditional oven annealing the quality of the films is still insufficient even after days of annealing. A process called hot zone annealing--where the thin film moves at an extremely slow speed through a heated region that temporarily raises its temperature to a point just above that at which the cylinders become disordered--has previously been used for creating highly ordered BCP thin films with a minimum of defects but little orientation control. For some polymer combinations, the order-disorder transition temperature is so high that it is virtually impossible for manufacturers to heat them sufficiently without degradation occurring.
To eliminate the time and temperature restraints without losing the order yielded by hot zone annealing, the NIST researchers developed a "cold zone" annealing system where the polymers are completely processed well below their order-disorder transition temperature. Properly controlled, the lower-temperature processing not only works with BCPs for which hot-zone annealing is impractical, but, as the NIST experiments showed, also repeatedly produces a highly ordered thin film in a matter of minutes.
NIST researchers also discovered that the alignment of the cylinders was controlled by the "cold zone" annealing conditions. Because it is simple, yields consistent product quality and has virtually no limitations on sample dimensions, the NIST method is being evaluated by microelectronic companies to fabricate highly ordered sub 30 nm features.
The next step, the NIST researchers say, is to better understand the fundamental processes that make the cold zone annealing system work so well and refine the measurements needed to evaluate its performance.
* B.C. Berry, A.W. Bosse, J.F. Douglas, R.L. Jones and A. Karim.Orientational order in block copolymer films zone annealed below the order-disorder transition temperature. Nano Letters, Vol. 7, No. 9, pp. 2789-2794, (Sept. 12, 2007).
Note: This story has been adapted from a news release issued by National Institute of Standards and Technology.

Fausto Intilla

www.oloscience.com

Better Displays On Laptop Computers, Cell Phones Coming Soon

Source:

http://www.sciencedaily.com/releases/2007/09/070918090800.htm

Science Daily — UCLA chemists working at the nanoscale have developed a new, inexpensive means of forcing luminescent polymers to give off polarized light and of confining that light to produce polymer-based lasers.

The research, which could lead to a brighter polarized light source for LEDs in laptop computers, cell phones and other consumer electronics devices, currently appears in the journal Nature Nanotechnology.
The research was conducted by UCLA professors of chemistry and California NanoSystems Institute members Sarah Tolbert and Benjamin J. Schwartz, and colleagues, including Hirokatsu Miyata, a research scientist with Canon's Nanocomposite Research division in Japan.
The researchers have succeeded in taking semiconducting polymers -- plastics that consist of long chains of atoms that work as semiconductors -- and stretching them out in a silica (glass) host matrix so that they have new optical properties.
"If you have polymer chains that can wiggle like spaghetti, it's hard to make them all point in the same direction," Tolbert said. "What we do is take tiny, nanometer-sized holes in a piece of glass and force the polymer chains into the holes. The holes are so small that the spaghetti chains have no space to coil up. They have to lie straight, and all the chains end up pointing in the same direction."
Because the chains point in the same direction, they absorb polarized light and give off polarized light. Lining up the polymer chains also provides advantages for laser technology, because all the chains can participate in the lasing process, and they can make the light polarized without the need for any external optical elements, Tolbert said.
As a postdoctoral fellow, Schwartz was one of the original discoverers in the 1990s that lasers could be made out of randomly oriented semiconducting polymer chains.
"Our new materials exploit the fact that the polymer chains are all lined up to make them into lasers that function very differently from lasers made out of random polymers," Schwartz said.
The manner in which the polymer chains incorporate into the porous glass of the silica matrix helps to confine the light in the material, enhancing the lasing process by producing what is known as a "graded-index waveguide." In most lasers, confining the light is typically done with external mirrors.
"Our materials don't need mirrors to function as lasers, because the material that's lasing is also serving to confine the light," Schwartz said.
In combination, the alignment of the polymer chains and the confinement of the light make it 20 times easier for the new materials to lase than if a randomly oriented polymer sample were used. And because polymers can be dissolved easily in solvents, they are inexpensive to process. The glass host matrix with the aligned nanoscale pores is also inexpensive to produce.
"Usually polarized and cheap don't go together," Tolbert said.
The research opens the possibility of additional applications for the new materials as a brighter polarized source for displays in products with LED-type displays, including cell phones, laptops and Palm Pilots.
"If you take an inexpensive light source with which you could excite the aligned polymer chains and get the chains to reemit, you potentially have a more efficient way to generate polarized light." Tolbert said. "This would allow displays to be brighter with less power consumption, and you could get longer battery life."
Tolbert has collaborated with Canon for years on the development of this class of new materials.
The research is federally funded by the National Science Foundation and the Office of Naval Research and privately funded by Canon.
In addition to Tolbert, Schwartz and Miyata, co-authors include UCLA researcher and former postdoctoral scholar Ignacio Martini, UCLA chemistry graduate student Ian Craig, and UCLA chemistry graduate student William Molenkamp.
Note: This story has been adapted from a news release issued by University of California, Los Angeles.

Fausto Intilla

www.oloscience.com

Lighter Gas Reduces Damage To Optics In Extreme Ultraviolet Lithography

Source:

http://www.sciencedaily.com/releases/2007/09/070912113900.htm

Science Daily — Researchers at the University of Illinois have discovered a way to generate light and reduce damage in a leading candidate for next-generation microelectronics lithography. The technique could help pack more power into smaller computer chips.

In the quest for creating computer chips with ever-smaller feature sizes, chip manufacturers are exploring extreme ultraviolet lithography as the next chip-printing technology. For a light source at the necessary wavelength, scientists have turned to a hot, ionized gas called a plasma, generated within a Z-pinch device. But, energetic ions produced in the plasma can damage the mirror responsible for collecting the light.
"By adding a lighter gas to the plasma, we can significantly reduce the damage and extend the lifetime of the collector optics," said David Ruzic, a professor of nuclear, plasma and radiological engineering and lead author of a paper that describes the technique in the June issue of the journal IEEE Transactions on Plasma Science.
In a Z-pinch device, xenon is fed into a chamber where it collides with a stream of electrons, producing a low-temperature and low-density plasma. This plasma then flows between two cylindrical electrodes, one positioned inside the other. (The "Z" in Z-pinch refers to the direction of current flow along the cylindrical electrodes.)
Next, a large current pulse heats the plasma, while a magnetic field generated by the pulse compresses and confines the plasma. The plasma becomes hotter and denser until it "pinches," creating the flash of light needed by the chip industry.
As the pulse passes, internal plasma pressure overcomes magnetic confinement, and the hot, dense plasma flies apart. The resulting fast and energetic ions can damage the delicate collector optics.
However, adding a small amount of a lighter gas, such as hydrogen, "significantly reduces both the number and the energy of xenon ions reaching the collector surface, thereby extending the collector's lifetime while having a negligible effect on the extreme ultraviolet light production," Ruzic said. The reduction in xenon energy occurs because the hydrogen ions shield the xenon ions from the high electric field created by the plasma.
"When the plasma flies apart, the less-massive electrons move faster than the hydrogen and xenon ions," Ruzic said. "The electric field induced by the moving electrons then pulls on the ions and accelerates them. Being much lighter than xenon ions, the hydrogen ions accelerate faster, and shield the xenon ions from some of the electric field."
By absorbing some of the plasma's energy, the hydrogen ions prevent the xenon ions from accelerating to the point where they damage the collector surface, thus prolonging the collector's lifetime.
Xenon is actually the second-best radiator for light at the desired wavelength, Ruzic said. "We can get three times as much light from tin, but tin is a condensable metal and makes quite a mess on the mirrors. We are now looking at ways to clean the mirrors during chip production."
With Ruzic, co-authors of the paper are U. of I. graduate students Keith Thompson and Josh Spencer, postdoctoral research associate Shailendra Srivastava, and former postdoctoral researcher associates Brian Jurczyk and Erik Antonsen.
Note: This story has been adapted from a news release issued by University of Illinois at Urbana-Champaign.

Fausto Intilla

www.oloscience.com

Tracking Down Builders Of Homemade Bombs

Source:

http://www.sciencedaily.com/releases/2007/09/070917150439.htm

Science Daily — Researchers in Australia are reporting development of a portable device to help track down builders of improvised explosive devices (IEDs) -- those homemade fertilizer bombs that have wreaked such havoc in terrorist attacks around the world.

Paul R. Haddad and colleagues point out that IEDs have become a mainstay weapon for terrorists, resulting in an urgent need for new technology to identify and eliminate the sources of the explosives. However, quickly and reliably identifying the chemicals used in these crude but deadly bombs remains a major challenge to investigators. IEDs are often made with a diverse array of conventional, easy-to-obtain materials that require slow and painstaking analysis in the laboratory following an explosion.
The new technology streamlines that process, quickly and accurately identifying the chemical composition of blast residues from IEDs in the field. It consists of an instrument, about the size of a briefcase, based on a modified form of capillary electrophoresis, a mainstay technology for separating components in a mixture. In the study, researchers used it to identify major components of blast residues in less than 10 minutes.
Their study will appear in the Sept. 15 issue of ACS' Analytical Chemistry.
Article: "Identification of Inorganic Improvised Explosive Devices by Analysis of Postblast Residues Using Portable Capillary Electrophoresis Instrumentation and Indirect Photometric Detection with a Light-Emitting Diode"
Note: This story has been adapted from a news release issued by American Chemical Society.

Fausto Intilla

www.oloscience.com

Salmon DNA Points The Way To Green Electronics

Source:

http://www.sciencedaily.com/releases/2007/09/070913132937.htm

Science Daily — Professor Andrew Steckl, a leading expert in light-emitting diodes, is intensifying the properties of LEDs by introducing biological materials, specifically salmon DNA.

Electrons move constantly — think of tiny particles with a negative charge and attention deficit disorder. It is through the movement of these electrons that electric current flows and light is created.
Steckl is an Ohio Eminent Scholar in UC’s Department of Electrical and Computer Engineering. He believed that if the electrons’ mobility could be manipulated, then new properties could be revealed.
In considering materials to introduce to affect the movement of the electrons, Steckl evaluated the source of materials with an eye to supply, especially materials that do not harm the environment.
“Biological materials have many technologically important qualities — electronic, optical, structural, magnetic,” says Steckl. “But certain materials are hard for to duplicate, such as DNA and proteins.” He also wanted a source that was widely available, would not have to be mined, and was not subject to any organization or country’s monopoly. His answer?
Salmon sperm.
“Salmon sperm is considered a waste product of the fishing industry. It’s thrown away by the ton,” says Steckl with a smile. “It’s natural, renewable and perfectly biodegradable.” While Steckl is currently using DNA from salmon, he thinks that other animal or plant sources might be equally useful. And he points out that for the United States, the green device approach takes advantage of something in which we continue to be a world leader — agriculture.
Steckl is pursuing this research in collaboration with the Air Force Research Laboratory. The research was featured recently in Naturephotonics and Applied Physics Letters.
“The Air Force had already been working with DNA for other applications when they came to us and said, ‘We know that you know how to make devices,’” quotes Steckl. “They also knew that they had a good source of salmon DNA.” It was a match made in heaven.
So began Steckl’s work with BioLEDs, devices that incorporate DNA thin films as electron blocking layers. Most of the devices existing today are based on inorganic materials, such as silicon. In the last decade, researchers have been exploring using naturally occurring materials in devices like diodes and transistors.
“The driving force, of course, is cost: cost to the producer, cost to the consumer and cost to the environment” Steckl points out, “but performance has to follow.”
And what a performance — lights, camera, action!
“DNA has certain optical properties that make it unique,” Steckl says. “It allows improvements in one to two orders of magnitude in terms of efficiency, light, brightness — because we can trap electrons longer.”
When electrons collide with oppositely charged particles, they produce very tiny packets of light called “photons.”
“Some of the electrons rushing by have a chance to say ‘hello,’ and get that photon out before they pass out,” Steckl explains. “The more electrons we can keep around, the more photons we can generate.” That’s where the DNA comes in, thanks to a bunch of salmon.
BioLEDs make colors brighter.
“DNA serves as a barrier that affects the motion of the electrons,” says Steckl. It allows Steckl and his fellow researcher, the Air Force’s Dr. James Grote, to control the brightness of the light that comes out.
“The story continues,” says Steckl, again smiling. “I’m receiving salmon sperm from researchers around the world wanting to see if their sperm is good enough.” The next step is to now replace some other materials that go into an LED with biomaterials. The long-term goal is be able to make “green” devices that use only natural, renewable and biodegradable materials.
This research was funded by the United States Air Force.
Here we have the “yin” of biological materials in photonic devices. See Steckl’s “yang” research placing electronics in biological materials: UC Engineering Research Widens Possibilities for Electronic Devices: NSF-funded engineering research on microfluidics at the University of Cincinnati widens the possibilities on the horizon for electronic devices.
Note: This story has been adapted from a news release issued by University of Cincinnati.

Fausto Intilla

www.oloscience.com

Ability To Write And Store Information On Electronic Devices Improved

Source:

http://www.sciencedaily.com/releases/2007/09/070913165155.htm

Science Daily — New research led by the U.S. Department of Energy's Argonne National Laboratory physicist Matthias Bode provides a more thorough understanding of new mechanisms, which makes it possible to switch a magnetic nanoparticle without any magnetic field and may enable computers to more accurately write and store information.

Bode and four colleagues at the University of Hamburg used a special scanning tunneling microscope equipped with a magnetic probe tip to force a spin current through a small magnetic structure. The researchers were able to show that the structure's magnetization direction is not affected by a small current, but can be influenced if the spin current is sufficiently high.
Most computers today use dynamic random access memory, or DRAM, in which each piece of binary digital information, or bit, is stored in an individual capacitor in an integrated circuit. Bode's experiment focused on magneto-resistive random access memory, or MRAM, which stores data in magnetic storage elements consisting of two ferromagnetic layers separated by a thin non-magnetic spacer. While one of the two layers remains polarized in a constant direction, the other layer becomes polarized through the application of an external magnetic field either in the same direction as the top layer (for a "0") or in the opposite direction (for a "1").
Traditionally, MRAM are switched by magnetic fields. As the bit size has shrunk in each successive generation of computers in order to accommodate more memory in the same physical area, however, they have become more and more susceptible to "false writes" or "far-field" effects, Bode said. In this situation, the magnetic field may switch the magnetization not only of the target bit but of its neighbors as well. By using the tip of the Scanning Tunneling Microscope (STM), which has the potential to resolve structures down to a single atom, the scientists were able to eliminate that effect.
Bode and his colleagues were the first ones who did such work with an STM that generates high spatial-resolution data. "If you now push just a current through this bit, there's no current through the next structure over," Bode said. "This is a really local way of writing information."
The high resolution of the STM tip might enable scientists to look for small impurities in the magnetic storage structures and to investigate how they affect the magnet's polarization. This technique could lead to the discovery of a material or a method to make bit switching more efficient. "If you find that one impurity helps to switch the structure, you might be able to intentionally dope the magnet such that it switches at lower currents," Bode said.
Results of this research were published in the September 14 issue of Science and related research was published earlier this year in Nature.
Funding for this work was provided by Deutsche Forschungsgemeinschaft and the European Union project ASPRINT. This work was conducted prior to Bode's arrival at Argonne. His research at Argonne will be predominately funded by DOE's Office of Basic Energy Sciences.
Note: This story has been adapted from a news release issued by DOE/Argonne National Laboratory.

Fausto Intilla

www.oloscience.com

Smallest Piece Of Art Ever Printed Could Herald Ultra-Tiny Nanowires, Biosensors And Optics For Future Chips

Source:

http://www.sciencedaily.com/releases/2007/09/070911210113.htm

Science Daily — IBM researchers in collaboration with scientists from the ETH Zurich have demonstrated a new, efficient and precise technique to “print” at the nanoscale.

The method, which allows the scientists to place individual particles precisely where they want them, could advance the development of nanoscale biosensors, ultra-tiny lenses that can bend light inside future optical chips, and the fabrication of nanowires that might be the basis of tomorrow’s computer chips.
Though still a few years from being used widely, the new technique shows promise for real world applications outside of the lab without major profound new inventions, and could lead to high-volume manufacturing techniques for nanostructures inside chips and other devices that are more efficient and cost less than today’s methods.
“This method opens up new ways to precisely and efficiently position various kinds of nanoparticles on different surfaces, a prerequisite for exploiting the unique properties of such nanoparticles and for making their use economically feasible,” explains Heiko Wolf, researcher in nanopatterning at IBM’s Zurich Research lab.
The achievement, published in the September issue of the journal Nature Nanotechnology, offers a promising and powerful new tool for use in a wide range of fields and industries such as biomedicine, electronics and IT that seek ways to exploit the often unique properties of so-called nanoparticles, which are defined as particles smaller than 100 nanometers.
Until now, standard top-down micro-fabrication techniques produce such tiny particles by in effect carving them out of a bigger piece of material. Printing, in contrast, adds ready-made nanoparticles onto a surface in a very efficient way and allows for different types of materials such as metals, polymers, semiconductors, and oxides to be combined in one process.
For the first time, the researchers printed particles as tiny as 60 nanometers -- roughly 100 times smaller than a human red blood cell -- with single-particle resolution to create nano-patterns ranging from simple lines to complex arrangements. Translating the resolution of these particles into a traditional printing term known as “dots per inch” or dpi, a standard measure that defines how many individual spots of ink can be printed on a certain area, the nanoprinting method yields 100,000 dots per inch, whereas common offset printing today operates at 1,500 dpi.
To demonstrate the efficiency and the versatility of their method, the researchers chose to print Robert Fludd’s 17th-century image of the sun, the alchemists’ symbol for gold. Quite fittingly, it is printed out of roughly 20,000 gold particles, each of them 60 nanometers in diameter. The printing method precisely placed one particle per dot, thus creating the smallest piece of artwork ever printed from single pigment particles.
Nanoprinting Applications
In biomedicine this printing process could, for example, be applied to the printing of large arrays of biofunctional beads that can detect and identify certain cells or markers in the body. One example could be rapid screening for cancer cells or heart attack markers. As part of new point-of-care diagnostic devices, regular arrays of functional beads could enable a fast and automated read-out that only needs the tiniest amounts of samples.
Nanoparticles can also interact with light. With the new method, optical materials with new properties could be printed, for example, for use in optoelectronic devices. So-called “metamaterials” could be created in which the printed structures are as small as the wavelength of the light and therefore act as if they were a single lens with unusual properties.
Moreover, the method holds promise for semiconductors. In one experiment, the researchers achieved the controlled placement of catalytic seed particles for growing semiconducting nanowires. Such nanowires are promising candidates for future transistors in microchips.
Printing on the Nanoscale
“In traditional gravure printing, a doctor blade is used to fill the recessed features of a printing plate with ink, in which pigment particles are randomly dispersed,” explains Tobias Kraus, of the nanopatterning team in Zurich. “In our high-resolution printing, a directed self-assembly process controls the arrangement of nanoparticles on the printing plate or template. The entire assembly is then printed onto a target surface, whereby the particle positions are precisely retained at a resolution that is three orders of magnitude higher than in conventional printing.”
The printing template geometries explored include lines to produce closely-packed nanoparticle wires, which could be used in molecular electronics; regularly spaced arrays of gold particles as seeds for nanowire growth; and arbitrary arrangements, such as the printed replica of the sun. The long-range accuracy, which measures the deviation from the desired arrangement on a large area, is similar to that of microcontact printing methods. The next steps will be to refine the method to achieve even higher accuracies, as would be required for large-scale integration in microelectronics, as well as to extend the method to print even smaller particles.
IBM’s Leadership in Nanotechnology
Today’s announcement builds on IBM’s leadership in nanotechnology: more than two decades after two IBM scientists won the Nobel Prize in Physics for their invention of the Scanning Tunneling Microscope (STM), which opened the door to the world of individual atoms for the first time, scientists and engineers from IBM Research continue to break new ground in nanoscience and technology.
The breakthrough also comes just two weeks after IBM unveiled two major scientific breakthroughs at the atomic scale: one a major step in understanding the ability for single atoms to maintain a specific magnetic direction, making them suitable for future data storage applications and the other a novel very robust and stable single-molecule switch that can be used as a modular building block for molecular computers.
Note: This story has been adapted from a news release issued by IBM.

Fausto Intilla

www.oloscience.com

Drawing Nanoscale Features The Fast And Easy Way

Source:

http://www.sciencedaily.com/releases/2007/09/070910110717.htm

Science Daily — Scientists at the Georgia Institute of Technology have developed a new technique for nanolithography that is extremely fast and capable of being used in a range of environments including air (outside a vacuum) and liquids.

Researchers have demonstrated the technique, known as thermochemical nanolithography, as a proof of concept. The technique may allow industry to produce a variety of nanopatterned structures, including nanocircuits, at a speed and scale that could make their manufacture commercially viable. The research, which has potential applications for fields ranging from the electronics industry to nanofluidics to medicine, appeared earlier this year in the journal Nano Letters.
The technique is surprisingly simple. Using an atomic force microscope (AFM), researchers heat a silicon tip and run it over a thin polymer film. The heat from the tip induces a chemical reaction at the surface of the film. This reaction changes the film’s chemical reactivity and transforms it from a hydrophobic substance to a hydrophilic one that can stick to other molecules. The technique is extremely fast and can write at speeds faster than millimeters per second. That’s orders of magnitude faster than the widely used dip-pen nanolithography (DPN), which routinely clocks at a speed of 0.0001 millimeters per second.
Using the new technique, researchers were able to pattern with dimensions down to 12 nanometers in width in a variety of environments. Other techniques typically require the addition of other chemicals to be transferred to the surface or the presence of strong electric fields. TCNL doesn’t have these requirements and can be used in humid environments outside a vacuum. By using an array of AFM tips developed by IBM, TCNL also has the potential to be massively scalable, allowing users to independently draw features with thousands of tips at a time rather than just one.
“Thermochemical nanolithography is a rapid and versatile technique that puts us much closer to achieving the speeds required for commercial applications,” said Elisa Riedo, assistant professor in Georgia Tech’s School of Physics. “Because we’re not transferring any materials from the AFM tip to the polymer surface (we are only heating it to change its chemical structure) this method can be intrinsically faster than other techniques.”
It’s the heated AFM tips that are one key to the new technique. Designed and fabricated by a group led by William King at the University of Illinois, the tips can reach temperatures hotter than 1,000 degrees Celsius. They can also be repeatedly heated and cooled 1 million times per second.
“The heated tip is the world’s smallest controllable heat source,” said King.
TCNL is also tunable. By varying the amount of heat, the speed and the distance of the tip to the polymer, researchers can introduce topographical changes or modulate the range of chemical changes produced in the material.
“By changing the chemistry of the polymer, we’ve shown that we can selectively attach new substances, like metal ions or dyes to the patterned regions of the film in order to greatly increase the technique’s functionality,” said Seth Marder, professor in Tech’s School of Chemistry and Biochemistry and director of the Center for Organic Photonics and Electronics. Marder’s group developed the thermally switchable polymers used in this study.
“We expect thermochemical nanolithography to be widely adopted because it’s conceptually simple and can be broadly applied,” said Marder. “The scope is limited only by one’s imagination to develop new chemistries and applications.”
For nanolithography to be commercially viable, it must be able to write at high speeds, be used in a variety of environments and write on a variety of materials. While the technique demonstrated here doesn’t yet allow writing at the centimeters per second rate that would be ideal, it does put researchers much closer to the goal than previous techniques. Once perfected, nanolithography could be used to draw nanocircuits for the electronics industry, create nanochannels for nanofluidics devices or be adapted for drug delivery or biosensing technologies. The research was supported by the National Science Foundation’s Center for Materials and Devices for Information Technology Research, the U.S. Department of Energy, the National Science Foundation, the Georgia Institute of Technology Research Foundation, the GT College of Sciences Cutting Edge Research Award and ONR Nanoelectronics. In addition to Riedo, Marder and King, the interdisciplinary research team consisted of Robert Szoszkiewicz, Takashi Okada, Simon Jones and Tai-De Li from Georgia Tech.
Note: This story has been adapted from a news release issued by Georgia Institute of Technology.

Fausto Intilla

www.oloscience.com

Single-Atom Data Storage, Single-Molecule Switching Could Lead To New Computer Devices

Source:

http://www.sciencedaily.com/releases/2007/09/070904081912.htm

Science Daily — IBM has announced two major scientific achievements in the field of nanotechnology that could one day lead to new kinds of devices and structures built from a few atoms or molecules.

Although still far from making their way into products, these breakthroughs will enable scientists at IBM and elsewhere to continue driving the field of nanotechnology, the exploration of building structures and devices out of ultra-tiny, atomic-scale components. Such devices might be used as future computer chips, storage devices, sensors and for applications nobody has imagined yet.
The work will be unveiled tomorrow in two reports being published by the journal Science.
In the first report, IBM scientists describe major progress in probing a property called magnetic anisotropy in individual atoms. This fundamental measurement has important technological consequences because it determines an atom’s ability to store information. Previously, nobody had been able to measure the magnetic anisotropy of a single atom.
With further work it may be possible to build structures consisting of small clusters of atoms, or even individual atoms, that could reliably store magnetic information. Such a storage capability would enable nearly 30,000 feature length movies or the entire contents of YouTube – millions of videos estimated to be more than 1,000 trillion bits of data – to fit in a device the size of an iPod. Perhaps more importantly, the breakthrough could lead to new kinds of structures and devices that are so small they could be applied to entire new fields and disciplines beyond traditional computing.
In the second report, IBM researchers unveiled the first single-molecule switch that can operate flawlessly without disrupting the molecule's outer frame -- a significant step toward building computing elements at the molecular scale that are vastly smaller, faster and use less energy than today's computer chips and memory devices.
In addition to switching within a single molecule, the researchers also demonstrated that atoms inside one molecule can be used to switch atoms in an adjacent molecule, representing a rudimentary logic element. This is made possible partly because the molecular framework is not disturbed.
The Science of The Small: Understanding the Magnetic Properties of Atoms
In the paper titled “Large Magnetic Anisotropy of a Single Atomic Spin Embedded in a Surface Molecular Network,” the researchers used IBM’s special scanning tunneling microscope (STM) to manipulate individual iron atoms and arranged them with atomic precision on a specially prepared copper surface. They then determined the orientation and strength of the magnetic anisotropy of the individual iron atoms.
Anisotropy is an important property for data storage because it determines whether or not a magnet can maintain a specific orientation. This in turn allows the magnet to represent either a “1” or “0,” which is the basis for storing data in computers.
“One of the major challenges for the IT industry today is shrinking the bit size used for data storage to the smallest possible features, while increasing the capacity,” said Gian-Luca Bona, manager of science and technology at the IBM Almaden Research Center in San Jose, California. “We are working at the ultimate edge of what is possible – and we are now one step closer to figuring out how to store data at the atomic level. Understanding the specific magnetic properties of atoms is the cornerstone of progressing toward new, more efficient ways to store data.”
Lilliputian Scale Devices: Single Molecule Logic Switching
In the paper titled “Current-Induced Hydrogen Tautomerization and Conductance Switching of Naphthalocyanine Molecules,” IBM researchers describe the ability to switch a single molecule “on” and “off,” a basic element of computer logic, using two hydrogen atoms within a naphthalocyanine organic molecule. Previously, researchers at IBM and elsewhere have demonstrated switching within single molecules, but the molecules would change their shape when switching, making them unsuitable for building logic gates for computer chips or memory elements.
Switches inside computer chips act like a light switch to turn the flow of electrons on and off and, when put together, make up the logic gates, which in turn make up electrical circuits. Having ever smaller switches allows the circuits to be shrunk to ever smaller sizes, making it possible to pack more circuits into a processor and boosting speed and performance.
These molecular switches could one day lead to computer chips with speeds as fast as today's fastest supercomputers, but much smaller in size; with some speculating even building computer chips so small they could be the size of a speck of dust or fit on the tip of a needle.
Development of conventional silicon-based CMOS chips is approaching its physical limits, and the IT industry is exploring new, truly disruptive technologies to achieve further increases in computer performance. Modular molecular logic is a possible candidate, though still several years from reality. The next step for the Research team is to build a series of these molecules into a circuit, then figure out how to network those together into a molecular chip.
The concept of using molecules as electronic components is still in its infancy. Only a few examples of individual molecules serving as switches or memory elements have been demonstrated to date. Most of these molecules are complex, three-dimensional structures and change their shape when switching. Placing them on a surface while maintaining their function is extremely difficult, making them unsuitable as building blocks for computer logic.
The switching within the molecule used by the IBM researchers is well-defined, highly-localized, reversible, intrinsic to the molecule, and does not involve changes in the molecular frame. Therefore, this molecule could be used as a building block for more complex molecular devices that serve as logic elements. As the shape of the molecule does not change during switching, single switches can be coupled in a controlled way. The switching process should also work with molecules embedded in more complex structures.
"Accidental" Science
Although the IBM Research team had been screening various molecules to discover if they would be suitable for molecular switches, in the case of naphthalocyanine, the tests being performed were not to observe switching but rather to examine molecular vibrations, since understanding vibrations of molecules is important for devices operating at the atomic level. During those tests, team members were surprised to observe results that were intriguing for switching at the molecular scale, and they shifted their focus from studying vibrations to studying switching, leading to this breakthrough.
“One of the beauties of doing exploratory science is that by researching one area, you sometimes stumble upon other areas of major significance,” said Gerhard Meyer, senior researcher in the nanoscale science group at the IBM Zurich lab. “Although the discovery of this breakthrough was accidental, it may prove to be significant for building the computers of the future.”
IBM’s Nanotechnology Leadership
These new results are the latest in a series of achievements in nanoscale science at IBM Research. Two IBM scientists in Switzerland won the 1986 Nobel Prize in physics for their early 1980s invention of the STM. Over the past 20 years, IBM Almaden researchers have pioneered the use of STMs for positioning atoms into precisely designed structures that reveal fundamental atomic-scale properties and may have potential uses in information storage, transmission and processing.
Note: This story has been adapted from a news release issued by IBM.

Fausto Intilla

www.oloscience.com

Low-cost Recipe For Patterning Microchips Developed

Source:

http://www.sciencedaily.com/releases/2007/09/070902193635.htm

Science Daily — Creating ultrasmall grooves on microchips -- a key part of many modern technologies -- is about to become as easy as making a sandwich, using a new process invented by Princeton engineers.

The simple, low-cost technique results in the self-formation of periodic lines, or gratings, separated by as few as 60 nanometers -- less than one ten-thousandth of a millimeter -- on microchips. Features of this size have many uses in optical, biological and electronic devices, including the alignment of liquid crystals in displays.
"It's like magic," said electrical engineer Stephen Chou, the Joseph C. Elgin Professor of Engineering. "This is a fundamentally different way of making nanopatterns."
The process, called fracture-induced structuring, is as easy as one-two-three. First, a thin polymer film is painted onto a rigid plate, such as a silicon wafer. Then, a second plate is placed on top, creating a polymer sandwich that is heated to ensure adhesion. Finally, the two plates are pried apart. As the film fractures, it automatically breaks into two complementary sets of nanoscale gratings, one on each plate. The distance between the lines, called the period, is four times the film thickness.
The ease of creating these lines is in marked contrast to traditional fabrication methods, which typically use a beam of electrons, ions, or a mechanical tip to "draw" the lines into a surface. These methods are serial processes which are extremely slow and therefore only suitable for areas one square millimeter or smaller. Other techniques suitable for larger areas have difficulties achieving small grating periods or producing a high yield, or they require complex and expensive processes. Fracture-induced structuring is not only simple and fast, but it enables patterning over a much larger area. The researchers have already demonstrated the ability of the technique to create gratings over several square centimeters, and the patterning of much large areas should be possible with further optimization of the technique.
"It's remarkable -- and counterintuitive -- that fracturing creates these regular patterns," said chemical engineering professor and dean of Princeton's graduate school William Russel. Russel and his graduate student Leonard Pease III teamed with Chou and his graduate students Paru Deshpande and Ying Wang to develop the technique.
A patent application has been filed on the process, which the researchers say is economically feasible for large-scale use in industry. The gratings generated by the fracturing process also could be used in conjunction with existing patterning methods. For example, the nanoimprinting method invented by Chou in the 1990s can use the gratings generated by fracture-induced structuring to create a mold that enables mass duplication of patterns with high precision at low cost.
As with many scientific discoveries, the fracture-induced structuring process was happened upon accidentally. Graduate students in the Chou and Russel groups were trying to use instabilities in various molten polymers (in essence, melted plastic) to create patterns when they discovered instead that fracturing a solid polymer film can generate the gratings automatically. The team seized upon this finding and established the optimal conditions for grating formation.
Next, the group plans to explore the fundamental science behind the process and investigate the interplays of various forces at such a small scale, according to Chou.
"And, we want to push the limit and see how small we can go," he said.
The researchers will publish their findings Sept. 2 in the online version of Nature Nanotechnology.
Abstract :
Self-formation of sub-60-nm half-pitch gratings with large areas through fracturing.
Periodic micro- and nanostructures (gratings) have many significant applications in electronic, optical, magnetic, chemical and biological devices and materials. Traditional methods for fabricating gratings by writing with electrons, ions or a mechanical tip are limited to very small areas and suffer from extremely low throughput. Interference lithography can achieve relatively large fabrication areas, but has a low yield for small-period gratings.
Photolithography, nanoimprint lithography, soft lithography and lithographically induced self-construction all require a prefabricated mask, and although electrohydrodynamic instabilities can self-produce periodic dots without a mask, gratings remain challenging.
Here, we report a new low-cost maskless method to self-generate nano- and microgratings from an initially featureless polymer thin film sandwiched between two flat relatively rigid plates. By simply prying apart the plates, the film fractures into two complementary sets of nonsymmetrical gratings, one on each plate, of the same period. The grating period is always four times the thickness of the glassy film, regardless of its molecular weight and chemical composition. Periods from 120 nm to 200 mm have been demonstrated across areas as large as two square centimeters.
Note: This story has been adapted from a news release issued by Princeton University, Engineering School.

Fausto Intilla

www.oloscience.com