Charlie Johnson, associate professor in the Department of Physics and Astronomy and the Department of Materials Science and Engineering at Penn, and colleagues created the self-balancing single-step technique using feedback controlled electromigration, or FCE. By using a novel arrangement of nanoscale shorts they showed that a balanced self-correcting process occurs that enables the simultaneous electromigration of sub-5 nm sized nanogaps. The nanogaps are controllably formed by carefully applying an electric current which pushes the atoms of the metallic wire through the process of electromigration.
In the study, the researchers described the simultaneous self-balancing of as many as 16 nanogaps using thin sheets of gold and FCE methodology originally developed at Penn. Using electron-beam lithography, Penn researchers constructed arrays of thin gold leads connected by narrow constrictions that were less than 100 nm in width. Introducing a voltage forced electrons to flow through these narrow constrictions in the gold, meeting with greater resistance as each constriction narrowed in response to electromigration. The narrower the constriction, the more the electrons were forced to the other, wider constrictions, in order to take a path of least resistance. This balanced interplay ensured that the electromigration process occurred simultaneously between the constrictions. After a few minutes, the applied electrons narrowed the constrictions until they opened to form gaps of roughly one nanometer in size with atomic-scale uniformity. By monitoring the electric-current feedback, researchers could adjust the size of the nanogaps as well.
Nanotechnology shows promise for revolutionizing materials and electronics by reducing the size and increasing the functionality of new composite materials; however, creating these materials is time consuming and costly, and it requires precise control at the atomic level, a scale that is difficult or impossible to achieve with current technology.
During the last several years there has been progress towards developing single nanometer-sized gaps and nanodevices. Yet their extremely low reproducibility has hindered any real chance of their use on the industrial scale, which is crucial to the development of the complex circuits that would be required to build, for example, a computer out of nanoelectronics.
“Reproducibility is one of the major issues facing nanotechnology, and it’s required us to depart from the standard ways of achieving this in micro-electronics processing.” Said Douglas Strachan of the Department of Materials Science and Engineering and the Department of Physics and Astronomy at Penn. “When you first hear of opening up a wire with a current, you usually think of a fuse. To think that this sort of technique could actually lead to atomically-precise nanoelectronics is sort of mind blowing.”
Danvers Johnston of the Department of Physics and Astronomy said, “Since it is impossible to mold nanoscale-size objects with any other lab tools, we direct the electrons to get them to do the work for us.”
Jordan Reese | EurekAlert!
Quantum optics allows us to abandon expensive lasers in spectroscopy
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Nano-watch has steady hands
22.11.2017 | University of Vienna
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
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22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy