Xiang Zhang greets the visitor to his airy, ground-floor office in Etcheverry Hall wearing cargo shorts, a colorful sport shirt and a broad smile. He’s relaxed enough to be on vacation, a deceptive look for someone who holds the Ernest S. Kuh chair as professor in the mechanical engineering department, directs the National Science Foundation’s Nanoscale Science and Engineering Center, was recently appointed director of the materials sciences division at Lawrence Berkeley National Laboratory and who in less than two decades has published more than 240 papers in such journals as ...
A significant breakthrough in laser technology has been reported by the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley. Scientists led by Xiang Zhang, a physicist with joint appointments at Berkeley Lab and UC Berkeley, have developed a unique microring laser cavity that can produce single-mode lasing even from a conventional multi-mode laser cavity. This ability to provide single-mode lasing on demand holds ramifications for a wide range of applications including optical metrology and interferometry,...
Nearly 20 years ago researcher Alex Zettl of the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) synthesized in his lab a new material never before seen by nature: boron nitride nanotubes, the strongest, lightest, most thermally conducting, and most chemically resistant fiber known to exist. Now a startup has licensed this technology with the aim of manufacturing boron nitride nanotubes for commercial use.
Berkeley Lab has licensed the invention to BNNT LLC, a startup company based in Newport News, Virginia. BNNT has also developed its own technology for...
The excessive atmospheric carbon dioxide that is driving global climate change could be harnessed into a renewable energy technology that would be a win for both the environment and the economy. That is the lure of artificial photosynthesis in which the electrochemical reduction of carbon dioxide is used to produce clean, green and sustainable fuels. However, finding a catalyst for reducing carbon dioxide that is highly selective and efficient has proven to be a huge scientific challenge. Meeting this challenge in the future should be easier thanks to new research results from Berkeley Lab...
A team of Berkeley Lab researchers believes it has uncovered the secret behind the unusual optoelectronic properties of single atomic layers of transition metal dichalcogenide (TMDC) materials, the two-dimensional semiconductors that hold great promise for nanoelectronic and photonic applications.
Using two-photon excitation spectroscopy, the researchers probed monolayers of tungsten disulfide, one of the most promising of 2D materials, and found evidence for the existence of excitonic dark states – energy states in which single photons can be neither absorbed nor emitted. These...
Berkeley Lab reports the first experimental observation of ultrafast charge transfer in photo-excited MX2 materials, the graphene-like two-dimensional semiconductors. Charge transfer time clocked in at under 50 femtoseconds, comparable to the fastest times recorded for organic photovoltaics.
A new argument has just been added to the growing case for graphene being bumped off its pedestal as the next big thing in the high-tech world by the two-dimensional semiconductors known as MX2 materials. An international collaboration of researchers led by a scientist with the U.S....
Berkeley Lab researchers have developed a technique for generating acoustic bottles in open air that can bend the paths of sound waves along prescribed convex trajectories. These self-bending bottle beams hold promise for ultrasonic imaging and therapy, and for acoustic cloaking, levitation and particle manipulation.
There’s a new wave of sound on the horizon carrying with it a broad scope of tantalizing potential applications, including advanced ultrasonic imaging and therapy, and acoustic cloaking, levitation and particle manipulation. Researchers with the U.S. Department of Energy (...
Berkeley Lab researchers have developed the first ab initio method for characterizing the properties of “hot carriers” in semiconductors. This should help clear a major road block to the development of new, more efficient solar cells.
A new and better way to study “hot” carriers in semiconductors, a major source of efficiency loss in solar cells, has been developed by scientists at Berkeley Lab. (Photo by Roy Kaltschmidt)
A new and better way to study “hot” carriers in semiconductors, a major source of efficiency loss in solar cells, has been developed by scientists...
From allowing our eyes to see, to enabling green plants to harvest energy from the sun, photochemical reactions – reactions triggered by light – are both ubiquitous and critical to nature. Photochemical reactions also play essential roles in high technology, from the creation of new nanomaterials to the development of more efficient solar energy systems. Using photochemical reactions to our best advantage requires a deep understanding of the interplay between the electrons and atomic nuclei within a molecular system after that system has been excited by light. A major advance towards...
An advance has been achieved towards next generation ultrasonic imaging with potentially 1,000 times higher resolution than today’s medical ultrasounds. Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated a technique for producing, detecting and controlling ultrahigh frequency sound waves at the nanometer scale.
Through a combination of subpicosecond laser pulses and unique nanostructures, a team led by Xiang Zhang, a faculty scientist with Berkeley Lab’s Materials Sciences Division, produced acoustic phonons...
