Physicists at the University of Pennsylvania are using a new technique to craft some of the tiniest metal nanostructures ever created, none larger than 10 nanometers, or 10,000 times smaller than the width of a single human hair.
The technique employs transmission electron beam ablation lithography, or TEBAL, to “carve” nanostructures from thin sheets of gold, silver, aluminum and other metals. TEBAL provides a more dependable method for producing quality versions of these microscopic devices, which are studied for their novel mechanical properties and their potential use in next-generation sensors and electronics. The method also permits simultaneous, real-time atomic imaging of the devices as they are made.
Traditional techniques for building nanodevices employ electron beam lithography but also require the use of polymers and chemicals in which the metal is evaporated. Typical results are closer to 50 nanometers in size and rarely as small as 10.
Marija Drndiæ, professor of physics at Penn, and her team created nanodisks, nanorings, nanowires, nanoholes and multi-terminal nano-transistors. The results were published in the journal Nano Letters.
“Many different approaches have been undertaken to fabricate the small structures needed to probe the phenomena that take place at the nanoscale, but the most widely used and versatile techniques are limited to tens of nanometers,” Drndiæ said. “Reliably and consistently fabricating devices at the sub-10-nanometer scale from the top down is generally still challenging, but our technique offers a route to this regime.”
Furthermore, the TEBAL method creates a resistance-free connection between the nanostructure and an electrical lead that might provide power to the device. The more parts involved, the greater the chance of a drop in electrical conduction between parts. Plus, structures made from bottom-up techniques, i.e., assembled from smaller components, typically first need to be placed on a chip and then connected to larger circuitry. Working with a single piece of metal means there are no additional parts to reduce efficiency.
The team used the superior control of the electron beam to reproduce multiple, identical copies of each structure. The ability to rapidly produce these tiny devices will provide the samples needed for a better understanding of the mechanical and conductive properties of metal at the molecular scale. Future research may lead to computer-based creation of such devices with more intricacy and faster production cycles.
Superconducting circuits, magnets and molecule-sized transistors are among the real-world applications that may result from this research. Penn physicists also propose that a more rapid method of DNA sequencing can be developed from this process, by threading DNA strands through an electronic “nanoport” that could read the base pairs that constitute a species’ genetic code.
Jordan Reese | EurekAlert!
Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas
22.09.2017 | Forschungszentrum MATHEON ECMath
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy