Tag Archives: letter-wafer-tech

Scientists at the Department of Energy’s Oak Ridge National Laboratory induced a two-dimensional material to cannibalize itself for atomic “building blocks” from which stable structures formed.

The findings, reported in Nature Communications, provide insights that may improve design of 2D materials for fast-charging energy-storage and electronic devices.

“Under our experimental conditions, titanium and carbon atoms can spontaneously form an atomically thin layer of 2D transition-metal carbide, which was never observed before,” said Xiahan Sang of ORNL.

He and ORNL’s Raymond Unocic led a team that performed in situ experiments using state-of-the-art scanning transmission electron microscopy (STEM), combined with theory-based simulations, to reveal the mechanism’s atomistic details.

“This study is about determining the atomic-level mechanisms and kinetics that are responsible for forming new structures of a 2D transition-metal carbide such that new synthesis methods can be realized for this class of materials,” Unocic added.

The starting material was a 2D ceramic called a MXene (pronounced “max een”). Unlike most ceramics, MXenes are good electrical conductors because they are made from alternating atomic layers of carbon or nitrogen sandwiched within transition metals like titanium.

The research was a project of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, a DOE Energy Frontier Research Center that explores fluid-solid interface reactions that have consequences for energy transport in everyday applications. Scientists conducted experiments to synthesize and characterize advanced materials and performed theory and simulation work to explain observed structural and functional properties of the materials. New knowledge from FIRST projects provides guideposts for future studies.

The high-quality material used in these experiments was synthesized by Drexel University scientists, in the form of five-ply single-crystal monolayer flakes of MXene. The flakes were taken from a parent crystal called “MAX,” which contains a transition metal denoted by “M”; an element such as aluminum or silicon, denoted by “A”; and either a carbon or nitrogen atom, denoted by “X.” The researchers used an acidic solution to etch out the monoatomic aluminum layers, exfoliate the material and delaminate it into individual monolayers of a titanium carbide MXene (Ti3C2).

The ORNL scientists suspended a large MXene flake on a heating chip with holes drilled in it so no support material, or substrate, interfered with the flake. Under vacuum, the suspended flake was exposed to heat and irradiated with an electron beam to clean the MXene surface and fully expose the layer of titanium atoms.

MXenes are typically inert because their surfaces are covered with protective functional groups–oxygen, hydrogen and fluorine atoms that remain after acid exfoliation. After protective groups are removed, the remaining material activates. Atomic-scale defects–“vacancies” created when titanium atoms are removed during etching–are exposed on the outer ply of the monolayer. “These atomic vacancies are good initiation sites,” Sang said. “It’s favorable for titanium and carbon atoms to move from defective sites to the surface.” In an area with a defect, a pore may form when atoms migrate.

“Once those functional groups are gone, now you’re left with a bare titanium layer (and underneath, alternating carbon, titanium, carbon, titanium) that’s free to reconstruct and form new structures on top of existing structures,” Sang said.

High-resolution STEM imaging proved that atoms moved from one part of the material to another to build structures. Because the material feeds on itself, the growth mechanism is cannibalistic.

“The growth mechanism is completely supported by density functional theory and reactive molecular dynamics simulations, thus opening up future possibilities to use these theory tools to determine the experimental parameters required for synthesizing specific defect structures,” said Adri van Duin of Penn State.

Most of the time, only one additional layer [of carbon and titanium] grew on a surface. The material changed as atoms built new layers. Ti3C2 turned into Ti4C3, for example.

“These materials are efficient at ionic transport, which lends itself well to battery and supercapacitor applications,” Unocic said. “How does ionic transport change when we add more layers to nanometer-thin MXene sheets?” This question may spur future studies.

“Because MXenes containing molybdenum, niobium, vanadium, tantalum, hafnium, chromium and other metals are available, there are opportunities to make a variety of new structures containing more than three or four metal atoms in cross-section (the current limit for MXenes produced from MAX phases),” Yury Gogotsi of Drexel University added. “Those materials may show different useful properties and create an array of 2D building blocks for advancing technology.”

At ORNL’s Center for Nanophase Materials Sciences (CNMS), Yu Xie, Weiwei Sun and Paul Kent performed first-principles theory calculations to explain why these materials grew layer by layer instead of forming alternate structures, such as squares. Xufan Li and Kai Xiao helped understand the growth mechanism, which minimizes surface energy to stabilize atomic configurations. Penn State scientists conducted large-scale dynamical reactive force field simulations showing how atoms rearranged on surfaces, confirming defect structures and their evolution as observed in experiments.

The researchers hope the new knowledge will help others grow advanced materials and generate useful nanoscale structures.

Rudolph Technologies, Inc. (NYSE: RTEC) today announced its new Dragonfly™ G2 platform, which incorporates many of the benefits of the Firefly™ system onto the Dragonfly platform, including higher sensitivity and throughput and the proprietary Clearfind™ Technology. The new system increases the options for advanced packaging customers to meet their wafer-based application challenges on a single platform. To date, customer evaluations have reported throughput increases greater than 50 percent over the first-generation Dragonfly system. The new Dragonfly G2 systems are scheduled to begin shipment in the latter part of the fourth quarter and will be highlighted at the SEMICON® Taiwan trade show September 5-7 in Rudolph’s booth N686-4F.

The Dragonfly G2 system achieves significant throughput and productivity increases using proprietary camera technology combined with stage speed and accuracy. Additionally, its modular architecture permits plug-and-play configurability of Rudolph’s technologies such as Truebump™ Technology, for more accurate bump height measurement, and Clearfind Technology, for non-visual residue detection. Streamlined software algorithms contribute to the faster throughput and enable the system to handle increasing bump counts, which have already exceeded 80 million bumps per wafer.

“Advanced packaging processes are evolving rapidly, with larger packages, shrinking features, and higher counts of smaller bumps on every wafer, and the Dragonfly G2 system is designed to meet these new challenges,” said Tim Kryman, senior director of corporate marketing at Rudolph Technologies. “At the same time, its increased throughput reduces cost-of-ownership and its configurable modular design lets one system do the work of two. Based on the positive feedback from customers’ beta testing we are expecting strong demand for this latest evolution of our technology. We expect the Dragonfly G2 system to meet our customers’ future inspection needs as increasing demands for higher quality products are driving more data with greater integrity and faster throughput to meet the growing volumes of consumer and auto electronics products.”

“An important driver for Rudolph Technologies is to increase our pace of innovation to ensure we are anticipating our customers’ roadmaps,” added Mike Goodrich, vice president and general manager of Rudolph’s Process Control Group. “We were very pleased to be able to demonstrate that commitment with the release of this Dragonfly G2 system. Not only have we significantly improved throughput and imaging capability, but we have also provided the powerful Clearfind Technology to make a compelling, no compromise, advanced packaging process control system.”

The Dragonfly G2 system can be ordered now with shipments expected to begin in Q4. First-generation Dragonfly systems can be retrofitted on-site with a second-generation upgrade kit.

Cymer, a manufacturer of excimer lasers used in semiconductor manufacturing, today announced the first customer installation of its XLR 860ix light source, which is expected to be used in the production of chips at advanced logic and memory nodes.

The XLR 860ix is a deep-ultraviolet (DUV) light source based on an Argon Fluoride excimer laser. The first customer installation was completed this month, and the XLR 860ix was paired up with ASML’s latest lithography system, the TWINSCAN NXT:2000i, for which the source was qualified earlier this year.

“The XLR 860ix, through improvements in high-speed controls and redesigned, on-board bandwidth metrology, reduces variations in bandwidth by a factor of two compared to its predecessor. This is an important achievement, since these variations contribute to errors in critical dimension (CD) uniformity, which in turn affects image quality and ultimately manufacturing yields. The improvement in the spectral stability of the light has been verified by our customers using early-access versions of the XLR 860ix, which gives us confidence that this light source will help to improve CD uniformity when used in the production of advanced ICs,” said Cymer Vice President Product Marketing Patrick O’Keeffe.

Ahead of the full release of the XLR860ix, Cymer made the key technologies available to customers in an early access program by upgrading existing light sources. Four such upgrades have been completed, and seven additional sources are planned to be upgraded by the end of the year. A total of seven customers are participating in the early access program. In response to strong customer demand, Cymer has rapidly shifted its production capacity to the XLR 860ix model for all future ArF immersion shipments.

“In addition to the early access program, we have also offered one of the key new technologies of the XLR 860ix as an upgrade to previous light source models. This upgrade, which extends the lifetime of the optics and the chamber, increases the time between service intervals by 33%, and thus allows our customers to better utilize their lithography systems and expose thousands of additional wafers per tool, per year. Our customers have aggressively taken advantage of this upgrade, with more than 400 upgrades completed within the past year. The majority of the upgraded systems are exceeding the targeted service intervals,” O’Keeffe said.

Semiconducting heterostructures have been key to the development of electronics and opto-electronics. Many applications in the infrared and terahertz frequency range exploit transitions, called intersubband transitions, between quantized states in semiconductor quantum wells. These intraband transitions exhibit very large oscillator strengths, close to unity. Their discovery in III-V semiconductor heterostructures depicted a huge impact within the condensed matter physics community and triggered the development of quantum well infrared photodetectors as well as quantum cascade lasers.

Schematic illustration of charge carriers confined within a TMD flake comprising different thicknesses. Charge carriers in the ground state (blue) can be excited upon resonant light excitation to a higher state (pink). Credit: ICFO/Fabien Vialla

Quantum wells of the highest quality are typically fabricated by molecular beam epitaxy (sequential growth of crystalline layers), which is a well-established technique. However, it poses two major limitations: Lattice-matching is required, restricting the freedom in materials to choose from, and the thermal growth causes atomic diffusion and increases interface roughness.

2D materials can overcome these limitations since they naturally form a quantum well with atomically sharp interfaces. They provide defect free and atomically sharp interfaces, enabling the formation of ideal QWs, free of diffusive inhomogeneities. They do not require epitaxial growth on a matching substrate and can therefore be easily isolated and coupled to other electronic systems such as Si CMOS or optical systems such as cavities and waveguides.

Surprisingly enough, intersubband transitions in few-layer 2D materials had never been studied before, neither experimentally nor theoretically. Thus, in a recent study published in Nature Nanotechnology, ICFO researchers Peter Schmidt, Fabien Vialla, Mathieu Massicotte, Klaas-Jan Tielrooij, Gabriele Navickaite, led by ICREA Prof at ICFO Frank Koppens, in collaboration with the Institut Lumière Matière – CNRS, Technical University of Denmark, Max Planck Institute for the Structure and Dynamics of Matter, CIC nanoGUNE, and the National Graphene Institute, report on the first theoretical calculations and first experimental observation of inter-sub-band transitions in quantum wells of few-layer semiconducting 2D materials (TMDs).

In their experiment, the team of researchers applied scattering scanning near-field optical microscopy (s-SNOM) as an innovative approach for spectral absorption measurements with a spatial resolution below 20 nm. They exfoliated TMDs, which comprisedterraces of different layer thicknesses over lateral sizes of about a few micrometers. They directly observed the intersubband resonances for these different quantum well thicknesses within a single device. They also electrostatically tuned the charge carrier density and demonstrated intersubband absorption in both the valence and conduction band. These observations were complemented and supported with detailed theoretical calculations revealing many-body and non-local effects.

The results of this study pave the way towards an unexplored field in this new class of materials and offer a first glimpse of the physics and technology enabled by intersubband transitions in 2D materials, such as infrared detectors, sources, and lasers with the potential for compact integration with Si CMOS.

A team of researchers led by the University of Minnesota has developed a new material that could potentially improve the efficiency of computer processing and memory. The researchers have filed a patent on the material with support from the Semiconductor Research Corporation, and people in the semiconductor industry have already requested samples of the material.

The findings are published in Nature Materials, a peer-reviewed scientific journal published by Nature Publishing Group.

This cross-sectional transmission electron microscope image shows a sample used for the charge-to-spin conversion experiment. The nano-sized grains of less than 6 nanometers in the sputtered topological insulator layer created new physical properties for the material that changed the behavior of the electrons in the material. Credit: Wang Group, University of Minnesota

“We used a quantum material that has attracted a lot of attention by the semiconductor industry in the past few years, but created it in unique way that resulted in a material with new physical and spin-electronic properties that could greatly improve computing and memory efficiency,” said lead researcher Jian-Ping Wang, a University of Minnesota Distinguished McKnight Professor and Robert F. Hartmann Chair in electrical engineering.

The new material is in a class of materials called “topological insulators,” which have been studied recently by physics and materials research communities and the semiconductor industry because of their unique spin-electronic transport and magnetic properties. Topological insulators are usually created using a single crystal growth process. Another common fabrication technique uses a process called Molecular Beam Epitaxy in which crystals are grown in a thin film. Both of these techniques cannot be easily scaled up for use in the semiconductor industry.

In this study, researchers started with bismuth selenide (Bi2Se3), a compound of bismuth and selenium. They then used a thin film deposition technique called “sputtering,” which is driven by the momentum exchange between the ions and atoms in the target materials due to collisions. While the sputtering technique is common in the semiconductor industry, this is the first time it has been used to create a topological insulator material that could be scaled up for semiconductor and magnetic industry applications.

However, the fact that the sputtering technique worked was not the most surprising part of the experiment. The nano-sized grains of less than 6 nanometers in the sputtered topological insulator layer created new physical properties for the material that changed the behavior of the electrons in the material. After testing the new material, the researchers found it to be 18 times more efficient in computing processing and memory compared to current materials.

“As the size of the grains decreased, we experienced what we call ‘quantum confinement’ in which the electrons in the material act differently giving us more control over the electron behavior,” said study co-author Tony Low, a University of Minnesota assistant professor of electrical and computer engineering.

Researchers studied the material using the University of Minnesota’s unique high-resolution transmission electron microscopy (TEM), a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image.

“Using our advanced aberration-corrected scanning TEM we managed to identify those nano-sized grains and their interfaces in the film,” said Andre Mkhoyan, a University of Minnesota associate professor of chemical engineering and materials science and electron microscopy expert.

Researchers say this is only the beginning and that this discovery could open the door to more advances in the semiconductor industry as well as related industries, such as magnetic random access memory (MRAM) technology.

“With the new physics of these materials could come many new applications,” said Mahendra DC (Dangi Chhetri), first author of the paper and a physics Ph.D. student in Professor Wang’s lab.

Wang agrees that this cutting-edge research could make a big impact.

“Using the sputtering process to fabricate a quantum material like a bismuth-selenide-based topological insulator is against the intuitive instincts of all researchers in the field and actually is not supported by any existing theory,” Wang said. “Four years ago, with a strong support from Semiconductor Research Corporation and the Defense Advanced Research Projects Agency, we started with a big idea to search for a practical pathway to grow and apply the topological insulator material for future computing and memory devices. Our surprising experimental discovery led to a new theory for topological insulator materials.

“Research is all about being patient and collaborating with team members. This time there was a big pay off,” Wang said.

A Princeton-led study has revealed an emergent electronic behavior on the surface of bismuth crystals that could lead to insights on the growing area of technology known as “valleytronics.”

The term refers to energy valleys that form in crystals and that can trap single electrons. These valleys potentially could be used to store information, greatly enhancing what is capable with modern electronic devices.

In the new study, researchers observed that electrons in bismuth prefer to crowd into one valley rather than distributing equally into the six available valleys. This behavior creates a type of electricity called ferroelectricity, which involves the separation of positive and negative charges onto opposite sides of a material. This study was made available online in May 2018 and published this month in Nature Physics.

The finding confirms a recent prediction that ferroelectricity arises naturally on the surface of bismuth when electrons collect in a single valley. These valleys are not literal pits in the crystal but rather are like pockets of low energy where electrons prefer to rest.

The researchers detected the electrons congregating in the valley using a technique called scanning tunneling microscopy, which involves moving an extremely fine needle back and forth across the surface of the crystal. They did this at temperatures hovering close to absolute zero and under a very strong magnetic field, up to 300,000 times greater than Earth’s magnetic field.

The behavior of these electrons is one that could be exploited in future technologies. Crystals consist of highly ordered, repeating units of atoms, and with this order comes precise electronic behaviors. Silicon’s electronic behaviors have driven modern advances in technology, but to extend our capabilities, researchers are exploring new materials. Valleytronics attempts to manipulate electrons to occupy certain energy pockets over others.

The existence of six valleys in bismuth raises the possibility of distributing information in six different states, where the presence or absence of an electron can be used to represent information. The finding that electrons prefer to cluster in a single valley is an example of “emergent behavior” in that the electrons act together to allow new behaviors to emerge that wouldn’t otherwise occur, according to Mallika Randeria, the first author on the study and a graduate student at Princeton working in the laboratory of Ali Yazdani, the Class of 1909 Professor of Physics.

“The idea that you can have behavior that emerges because of interactions between electrons is something that is very fundamental in physics,” Randeria said. Other examples of interaction-driven emergent behavior include superconductivity and magnetism.

A team of engineers at the University of Delaware is developing next-generation smart textiles by creating flexible carbon nanotube composite coatings on a wide range of fibers, including cotton, nylon and wool. Their discovery is reported in the journal ACS Sensors where they demonstrate the ability to measure an exceptionally wide range of pressure – from the light touch of a fingertip to being driven over by a forklift.

Fabric coated with this sensing technology could be used in future “smart garments” where the sensors are slipped into the soles of shoes or stitched into clothing for detecting human motion.

Carbon nanotubes give this light, flexible, breathable fabric coating impressive sensing capability. When the material is squeezed, large electrical changes in the fabric are easily measured.

“As a sensor, it’s very sensitive to forces ranging from touch to tons,” said Erik Thostenson, an associate professor in the Departments of Mechanical Engineering and Materials Science and Engineering.

Nerve-like electrically conductive nanocomposite coatings are created on the fibers using electrophoretic deposition (EPD) of polyethyleneimine functionalized carbon nanotubes.

“The films act much like a dye that adds electrical sensing functionality,” said Thostenson. “The EPD process developed in my lab creates this very uniform nanocomposite coating that is strongly bonded to the surface of the fiber. The process is industrially scalable for future applications.”

Now, researchers can add these sensors to fabric in a way that is superior to current methods for making smart textiles. Existing techniques, such as plating fibers with metal or knitting fiber and metal strands together, can decrease the comfort and durability of fabrics, said Thostenson, who directs UD’s Multifunctional Composites Laboratory. The nanocomposite coating developed by Thostenson’s group is flexible and pleasant to the touch and has been tested on a range of natural and synthetic fibers, including Kevlar, wool, nylon, Spandex and polyester. The coatings are just 250 to 750 nanometers thick — about 0.25 to 0.75 percent as thick as a piece of paper — and would only add about a gram of weight to a typical shoe or garment. What’s more, the materials used to make the sensor coating are inexpensive and relatively eco-friendly, since they can be processed at room temperature with water as a solvent.

Exploring Future Applications

One potential application of the sensor-coated fabric is to measure forces on people’s feet as they walk. This data could help clinicians assess imbalances after injury or help to prevent injury in athletes. Specifically, Thostenson’s research group is collaborating with Jill Higginson, professor of mechanical engineering and director of the Neuromuscular Biomechanics Lab at UD, and her group as part of a pilot project funded by Delaware INBRE. Their goal is to see how these sensors, when embedded in footwear, compare to biomechanical lab techniques such as instrumented treadmills and motion capture.

During lab testing, people know they are being watched, but outside the lab, behavior may be different.

“One of our ideas is that we could utilize these novel textiles outside of a laboratory setting — walking down the street, at home, wherever,” said Thostenson.

Sagar Doshi, a doctoral student in mechanical engineering at UD, is the lead author on the paper. He worked on making the sensors, optimizing their sensitivity, testing their mechanical properties and integrating them into sandals and shoes. He has worn the sensors in preliminary tests, and so far, the sensors collect data that compares with that collected by a force plate, a laboratory device that typically costs thousands of dollars.

“Because the low-cost sensor is thin and flexible the possibility exists to create custom footwear and other garments with integrated electronics to store data during their day-to-day lives,” Doshi said. “This data could be analyzed later by researchers or therapists to assess performance and ultimately bring down the cost of healthcare.”

This technology could also be promising for sports medicine applications, post-surgical recovery, and for assessing movement disorders in pediatric populations.

“It can be challenging to collect movement data in children over a period of time and in a realistic context,” said Robert Akins, Director of the Center for Pediatric Clinical Research and Development at the Nemours – Alfred I. duPont Hospital for Children in Wilmington and affiliated professor of materials science and engineering, biomedical engineering and biological sciences at UD. “Thin, flexible, highly sensitive sensors like these could help physical therapists and doctors assess a child’s mobility remotely, meaning that clinicians could collect more data, and possibly better data, in a cost-effective way that requires fewer visits to the clinic than current methods do.”

Interdisciplinary collaboration is essential for the development of future applications, and at UD, engineers have a unique opportunity to work with faculty and students from the College of Health Sciences on UD’s Science, Technology and Advanced Research (STAR) Campus.

“As engineers, we develop new materials and sensors but we don’t always understand the key problems that doctors, physical therapists and patients are facing,” said Doshi. “We collaborate with them to work on the problems they are facing and either direct them to an existing solution or create an innovative solution to solve that problem.”

Thostenson’s research group also uses nanotube-based sensors for other applications, such as structural health monitoring.

“We’ve been working with carbon nanotubes and nanotube-based composite sensors for a long time,” said Thostenson, who is affiliated faculty at UD’s Center for Composite Materials (UD-CCM). Working with researchers in civil engineering his group has pioneered the development of flexible nanotube sensors to help detect cracks in bridges and other types of large-scale structures. “One of the things that has always intrigued me about composites is that we design them at varying lengths of scale, all the way from the macroscopic part geometries, an airplane or an airplane wing or part of a car, to the fabric structure or fiber level. Then, the nanoscale reinforcements like carbon nanotubes and graphene give us another level to tailor the material structural and functional properties. Although our research may be fundamental, there is always an eye towards applications. UD-CCM has a long history of translating fundamental research discoveries in the laboratory to commercial products through UD-CCM’s industrial consortium.”

If you’re ever unlucky enough to have a car with metal tires, you might consider a set made from a new alloy engineered at Sandia National Laboratories. You could skid — not drive, skid — around the Earth’s equator 500 times before wearing out the tread.

Sandia’s materials science team has engineered a platinum-gold alloy believed to be the most wear-resistant metal in the world. It’s 100 times more durable than high-strength steel, making it the first alloy, or combination of metals, in the same class as diamond and sapphire, nature’s most wear-resistant materials. Sandia’s team recently reported their findings in Advanced Materials. “We showed there’s a fundamental change you can make to some alloys that will impart this tremendous increase in performance over a broad range of real, practical metals,” said materials scientist Nic Argibay, an author on the paper.

Although metals are typically thought of as strong, when they repeatedly rub against other metals, like in an engine, they wear down, deform and corrode unless they have a protective barrier, like additives in motor oil.

In electronics, moving metal-to-metal contacts receive similar protections with outer layers of gold or other precious metal alloys. But these coatings are expensive. And eventually they wear out, too, as connections press and slide across each other day after day, year after year, sometimes millions, even billions of times. These effects are exacerbated the smaller the connections are, because the less material you start with, the less wear and tear a connection can endure before it no longer works.

With Sandia’s platinum-gold coating, only a single layer of atoms would be lost after a mile of skidding on the hypothetical tires. The ultradurable coating could save the electronics industry more than $100 million a year in materials alone, Argibay says, and make electronics of all sizes and across many industries more cost-effective, long-lasting and dependable — from aerospace systems and wind turbines to microelectronics for cell phones and radar systems.

“These wear-resistant materials could potentially provide reliability benefits for a range of devices we have explored,” said Chris Nordquist, a Sandia engineer not involved in the study. “The opportunities for integration and improvement would be device-specific, but this material would provide another tool for addressing current reliability limitations of metal microelectronic components.”

New metal puts an old theory to rest

You might be wondering how metallurgists for thousands of years somehow missed this. In truth, the combination of 90 percent platinum with 10 percent gold isn’t new at all.

But the engineering is new. Argibay and coauthor Michael Chandross masterminded the design and the new 21st century wisdom behind it. Conventional wisdom says a metal’s ability to withstand friction is based on how hard it is. The Sandia team proposed a new theory that says wear is related to how metals react to heat, not their hardness, and they handpicked metals, proportions and a fabrication process that could prove their theory.

“Many traditional alloys were developed to increase the strength of a material by reducing grain size,” said John Curry, a postdoctoral appointee at Sandia and first author on the paper. “Even still, in the presence of extreme stresses and temperatures many alloys will coarsen or soften, especially under fatigue. We saw that with our platinum-gold alloy the mechanical and thermal stability is excellent, and we did not see much change to the microstructure over immensely long periods of cyclic stress during sliding.”

Now they have proof they can hold in their hands. It looks and feels like ordinary platinum, silver-white and a little heavier than pure gold. Most important, it’s no harder than other platinum-gold alloys, but it’s much better at resisting heat and a hundred times more wear resistant.

The team’s approach is a modern one that depended on computational tools. Argibay and Chandross’ theory arose from simulations that calculated how individual atoms were affecting the large-scale properties of a material, a connection that’s rarely obvious from observations alone. Researchers in many scientific fields use computational tools to take much of the guesswork out of research and development.

“We’re getting down to fundamental atomic mechanisms and microstructure and tying all these things together to understand why you get good performance or why you get bad performance, and then engineering an alloy that gives you good performance,” Chandross said.

A slick surprise

Still, there will always be surprises in science. In a separate paper published in Carbon, the Sandia team describes the results of a remarkable accident. One day, while measuring wear on their platinum-gold, an unexpected black film started forming on top. They recognized it: diamond-like carbon, one of the world’s best man-made coatings, slick as graphite and hard as diamond. Their creation was making its own lubricant, and a good one at that.

Diamond-like carbon usually requires special conditions to manufacture, and yet the alloy synthesized it spontaneously.

“We believe the stability and inherent resistance to wear allows carbon-containing molecules from the environment to stick and degrade during sliding to ultimately form diamond-like carbon,” Curry said. “Industry has other methods of doing this, but they typically involve vacuum chambers with high temperature plasmas of carbon species. It can get very expensive.”

The phenomenon could be harnessed to further enhance the already impressive performance of the metal, and it could also potentially lead to a simpler, more cost-effective way to mass-produce premium lubricant.

Adesto Technologies (NASDAQ:IOTS), a provider of application-specific semiconductors for the IoT era, announced it will present new research showing the significant potential for Resistive RAM (RRAM) technology in high-reliability applications such as automotive. Adesto Fellow Dr. John Jameson, who led the research team, will share the results at the ESSCIRC-ESSDERC 48th European Solid-State Device Research Conference, being held in Germany on September 4th, 2018.

RRAM has great potential to become a widely used, low-cost and simple embedded non-volatile memory (NVM), as it utilizes simple cell structures and materials which can be integrated into existing manufacturing flows with as little as one additional mask. However, many RRAM technologies to-date have faced integration and reliability challenges. Adesto’s engineers will describe recent innovations that significantly increase the reliability of Adesto’s RRAM technology (trademarked as CBRAM®), making it a promising candidate for high-reliability applications. CBRAM consumes less power, requires fewer processing steps, and operates at lower voltages as compared to conventional embedded flash technologies.

“We’re delighted to share our latest RRAM research with the prestigious technical community at ESSCIRC-ESSDERC,” said Dr. Venkatesh Gopinath, VP of CBRAM and RRAM Technology and Production Development at Adesto. “For the first time, RRAM is being demonstrated as an ideal low-cost, one-mask embedded NVM for high-reliability applications. Adesto was the first company to bring commercial RRAM devices to market, and now our CBRAM technology is production-proven for IoT and other ultra-low power applications. Our continued innovation and advancements will bring the benefits of CBRAM to an even broader range of applications.”

Dr. Jameson will present the Adesto research on Tuesday, September 4th at 15:00 local time.

Pioneering engineers working with terahertz frequency technology have been researching how individual frequencies are selected when a laser is turned on, and how quickly the selection is made.

The development of specific terahertz equipment has allowed them to investigate this process for the first time. Their results, published in Nature Communications, will underpin the future development of semiconductor lasers, including those used in public and private sector-owned telecommunications systems.

For many years, it has been predicted that operating frequencies within semiconductor lasers stabilise on a timescale of a few nanoseconds (ie a few billionths of a second) and can be changed within a few hundreds of picoseconds (ie thousandths of a nanosecond).

Until now, though, no detector has been capable of measuring and proving this precisely, and the best results have only been achieved on nanosecond timescales, which are too slow to allow really efficient analysis or to be used to develop the most effective new systems.

The University of Leeds researchers, working with international colleagues at École Normal Supérieure in Paris, France and the University of Queensland in Brisbane, Australia have now used terahertz frequency quantum cascade lasers and a technique called terahertz time-domain spectroscopy to understand this laser stabilisation process.

The terahertz-powered technology can measure the wavelength of light in periods of femtoseconds (ie millionths of a nanosecond) giving unprecedented levels of detail. By knowing the speed at which wavelengths change within lasers, and what happens during that process within miniscule time frames, more efficient devices and systems can be built.

The Leeds elements of the study were carried out in the University’s Terahertz Photonics Laboratory, part of the University’s Bragg Centre for Materials Research.

Dr Iman Kundu, principal author of the research paper explaining the group’s findings, said: “We’ve exploited the ultrafast detection capabilities of terahertz technology to watch laser emissions evolve from multiple colours to a single wavelength over less than a billionth of a second.

“Now that we can see the detailed emission of the lasers over such incredibly small time frames, we can see how the wavelength of light changes as one moves from one steady state to a new steady state.

“The benefits for commercial systems designers are potentially significant. Terahertz technology isn’t available to many sectors, but we believe its value lies in being able to highlight trends and explain the detailed operation of integrated photonic devices, which are used in complex imaging systems which might be found in the pharmaceutical or electronics sectors.

“Designers can then apply these findings to lasers operating at different parts of the electromagnetic spectrum, as the underlying physics will be very similar.”

Professor Edmund Linfield, Chair of Terahertz Electronics at the University of Leeds, who was also involved in the study said: “We’re using the highly advanced capabilities of terahertz technology to shine a light on the operation of lasers.

“Our research is aimed at showing engineers and developers where to look to drive increased performance in their own systems. By doing this, we will increase the global competitiveness of the UK’s science and engineering base.”