Berkeley Lab researchers fabricated the first fully 2D field-effect transistor from layers of molybdenum disulfide, hexagonal boron nitride and graphene held together by van der Waals bonding. Faster electronic device architectures are in the offing with the unveiling of the world’s first fully two-dimensional field-effect transistor (FET) by researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab). Unlike conventional FETs made from silicon, these 2D FETs suffer no performance drop-off under high voltages and provide high electron mobility, even when scaled to a monolayer in thickness. Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of electrical engineering and computer science, led this research in which 2D heterostructures were fabricated from layers of a transition metal dichalcogenide, hexagonal boron nitride and graphene stacked via van der Waals interactions. “Our work represents an important stepping stone towards the realization of a new class of electronic devices in which interfaces based on van der Waals interactions rather than covalent bonding provide an unprecedented degree of control in material engineering and device exploration,” Javey says. “The results demonstrate the promise of using an all-layered material system for future electronic applications.” Javey is the corresponding author
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In the mid-1970s, theoretical astrophysicist Kip Thorne, working with collaborator Anna Zytkow, postulated the existence of a bizarre form of star. Now known as Thorne-Zytkow objects (TZOs), these bodies were the product of the merger of two separate stars: one a giant star, the second a neutron star. They were able to calculate several likely properties of these stars, making predictions for what they might look like. But in the intervening years, none have been discovered.
Anna Zytkow, however, did not give up the search. And now, 40 years later, she may have spotted one. She and three collaborators (Phil Massey, Nidia Morrell, and Emily Levesque) have reported what may be the first observational evidence that TZOs exist.
Neutron stars are the cores of massive stars that have undergone a supernova. Their massive gravity compresses matter so much that an object the mass of the Sun can squeeze into a sphere about 20 km across. At these densities, matter is compressed down to neutrons—and possibly even a sea of subatomic particles.
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A device that essentially listens for light waves could help open up the last frontier of the electromagnetic spectrum—the terahertz range. So-called T-rays, which are light waves too long for human eyes to see, could help airport security guards find chemical and other weapons. They might let doctors image body tissues with less damage to healthy areas. And they could give astronomers new tools to study planets in other solar systems. Those are just a few possible applications. But because terahertz frequencies fall between the capabilities of the specialized tools presently used to detect light, engineers have yet to efficiently harness them. The U-M researchers demonstrated a unique terahertz detector and imaging system that could bridge this terahertz gap. “We convert the T-ray light into sound,” said Jay Guo, U-M professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. “Our detector is sensitive, compact and works at room temperature, and we’ve made it using an unconventional approach.” The sound the detector makes is too high for human ears to hear. The terahertz gap is a sliver between the microwave and infrared bands of the electromagnetic spectrum—the range of light’s wavelengths and frequencies. That spectrum spans
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Imagine being able to carry all the juice you needed to power your MP3 player, smartphone and electric car in the fabric of your jacket? Sounds like science fiction, but it may become a reality thanks to breakthrough technology developed at a University of Central Florida research lab. So far electrical cables are used only to transmit electricity. However, nanotechnology scientist and professor Jayan Thomas and his Ph.D. student Zenan Yu have developed a way to both transmit and store electricity in a single lightweight copper wire. Jayan Thomas is a professor and scientist at the University of Central Florida. Credit: UCF Their work is the focus of the cover story of the June 30 issue of the material science journal Advanced Materials and science magazine Nature has published a detailed discussion about this technology in the current issue. “It’s an interesting idea,” Thomas said. “When we did it and started talking about it, everyone we talked to said, ‘Hmm, never thought of that. It’s unique.’” Copper wire is the starting point but eventually, Thomas said, as the technology improves, special fibers could also be developed with nanostructures to conduct and store energy. More immediate applications could be seen in the design
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PETRA III pioneers protein serial crystallography at synchrotrons Using DESY’s synchrotron light source PETRA III, scientists have pioneered a new way to analyse delicate biomolecules. The novel approach, borrowed from a new class of high-intensity X-ray sources called free-electron lasers (FELs), could reveal the atomic structure of proteins that were previously inaccessible to synchrotrons, as the team led by Prof. Henry Chapman from the Hamburg Center for Free-Electron Laser Science CFEL reports in the scientific journal of the International Union of Crystallography, IUCrJ. CFEL is a joint institution of DESY, the University of Hamburg and the Max Planck Society. Electron density map of lysozyme at 2.1 Å resolution calculated from 40,233 single crystal indexed diffraction patterns. The atomic structure of biomolecules can reveal the mechanisms underlying their function in the organism, leading to improved biological insight with the potential to enable the development of new medicines. The standard technique for elucidating the atomic structure of proteins involves shining a bright beam of X-rays onto a protein crystal. The crystal scatters the X-rays in a characteristic way, and from the resulting diffraction pattern the inner structure of the crystal can be calculated, yielding the atomic structure of the protein. “But being jammed
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