Tag Archives: letter-pulse-tech

Novel photonics materials are becoming pivotal for energy conversion, communications, and sensing, largely because there is a global desire to enhance energy efficiency, and reduce electricity consumption. As Dr. Can Bayram, assistant professor in the Department of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign, notes, “Who doesn’t want to consume less electricity for the same quality of lighting?”

When the 2014 Nobel Prize in Physics was awarded to a trio of researchers for inventing a new (In)GaN-based energy-efficient, more environmentally friendly light source, this idea was brought to the forefront and gained more widespread recognition.

In related work, the Innovative COmpound semiconductoR Laboratory (ICOR) team led by Prof. Bayram has published a well-received paper titled “High internal quantum efficiency ultraviolet emission from phase-transition cubic GaN integrated on nanopatterned Si(100)”. Richard Liu, a Ph.D. candidate advised by Prof. Bayram, and whose primary research areas are optoelectronics and nanophotonics, is the lead author for this paper.

The team’s paper and its promise for a novel emitter have recently been featured in Compound Semiconductor and Semiconductor Today.

GaN materials (also known as III-Nitrides) are one of the most exotic photonic materials, and in the U of I team’s work, they investigate a new phase of Gallium Nitride materials: cubic. Using aspect ratio nanopatterning technology, they report a hexagonal-to-cubic phase transition process in GaN, enabled through aspect ratio patterning of silicon substrate. The emission efficiency of optimized cubic GaN, thanks to the polarization-free nature of cubic GaN, is measured to be approximately 29%, in sharp contrast to the general percentages of 12%, 8%, and 2%, respectively, of conventional hexagonal GaN on sapphire, hexagonal free-standing GaN, and hexagonal GaN on Si.

Bayram comments that “New photonic materials are critical in next-generation energy conversion devices. GaN-on-Si, enabled through phase-transition technology, provides an efficient, scalable, and environmental solution for integrated visible photonics.”

The discovery of graphene, with its high strength-to-weight ratio, flexibility, electrical conductivity, and ability to form an impenetrable barrier, led to an explosion of interest in 2D solids. Weak, long-range interactions give 2D solids some of their most interesting behaviors; therefore, understanding these interactions is crucial for further developing these materials. However, experimental support for theoretical modelling of the van der Waals interactions that hold these materials’ layers together has been wanting.

Now, an international research group led by the University of Tsukuba and Aarhus University has performed synchrotron X-ray diffraction experiments on titanium disulfide (TiS2) — a transition metal dichalogenide (TMD) material with a layered 2D structure–and compared the results with theoretical calculations. Their benchmark work was recently published in Nature Materials.

“The interaction between layers in van der Waals materials such as TiS2 has a significant bearing on their modification, processing, and assembly,” study co-author Eiji Nishibori says. “By modelling experimental synchrotron data and comparing it with density functional theory calculations, we revealed surprising information about the nature of the electron sharing between layers in these materials.”

TiS2 is an archetypal van der Waals material, with layers comprising sheets of titanium and sulfur interacting through strong chemical bonds, where electrons are shared between atoms, resulting in a relatively fixed structure. Between these sheets, long-range S…S van der Waals interactions attract the layers to one another allowing them to build up, forming solid materials. These interactions are known to be much weaker than those within the 2D sheets, however, using high-energy synchrotron X-ray radiation to precisely measure a single TiS2 crystal, the researchers were able to show that the interlayer interactions are in fact stronger than theory indicates, and involve significant electron sharing.

“This work provides a fundamental understanding of an exciting class of materials with numerous potential applications in technologies such as ion batteries, catalysis, and superconductors,” lead author Hidetaka Kasai says. “Our experiments are the first to reveal the true nature of the interactions that make 2D materials so interesting, and we hope they will underpin many future developments in this area.”

The outstanding agreement of the synchrotron diffraction data with theoretical calculations in describing the intralayer Ti-S interactions, supports the validity of these new-found differences for the long-range interactions across the interlayer gaps. The findings are expected to substantially contribute to the fundamental understanding of weak chemical bonding in 2D layered materials in general, and to the development of TMD materials.

 

A silicon-based quantum computing device could be closer than ever due to a new experimental device that demonstrates the potential to use light as a messenger to connect quantum bits of information — known as qubits — that are not immediately adjacent to each other. The feat is a step toward making quantum computing devices from silicon, the same material used in today’s smartphones and computers.

In a step forward for quantum computing in silicon -- the same material used in today's computers -- researchers successfully coupled a single electron's spin, represented by the dot on the left, to light, represented as a wave passing over the electron, which is trapped in a double-welled silicon chamber known as a quantum dot. The goal is to use light to carry quantum information to other locations on a futuristic quantum computing chip. Credit: Image courtesy of Emily Edwards, University of Maryland.

In a step forward for quantum computing in silicon — the same material used in today’s computers — researchers successfully coupled a single electron’s spin, represented by the dot on the left, to light, represented as a wave passing over the electron, which is trapped in a double-welled silicon chamber known as a quantum dot. The goal is to use light to carry quantum information to other locations on a futuristic quantum computing chip. Credit: Image courtesy of Emily Edwards, University of Maryland.

The research, published in the journal Nature, was led by researchers at Princeton University in collaboration with colleagues at the University of Konstanz in Germany and the Joint Quantum Institute, which is a partnership of the University of Maryland and the National Institute of Standards and Technology.

The team created qubits from single electrons trapped in silicon chambers known as double quantum dots. By applying a magnetic field, they showed they could transfer quantum information, encoded in the electron property known as spin, to a particle of light, or photon, opening the possibility of transmitting the quantum information.

“This is a breakout year for silicon spin qubits,” said Jason Petta, professor of physics at Princeton. “This work expands our efforts in a whole new direction, because it takes you out of living in a two-dimensional landscape, where you can only do nearest-neighbor coupling, and into a world of all-to-all connectivity,” he said. “That creates flexibility in how we make our devices.”

Quantum devices offer computational possibilities that are not possible with today’s computers, such as factoring large numbers and simulating chemical reactions. Unlike conventional computers, the devices operate according to the quantum mechanical laws that govern very small structures such as single atoms and sub-atomic particles. Major technology firms are already building quantum computers based on superconducting qubits and other approaches.

“This result provides a path to scaling up to more complex systems following the recipe of the semiconductor industry,” said Guido Burkard, professor of physics at the University of Konstanz, who provided guidance on theoretical aspects in collaboration with Monica Benito, a postdoctoral researcher. “That is the vision, and this is a very important step.”

Jacob Taylor, a member of the team and a fellow at the Joint Quantum Institute, likened the light to a wire that can connect spin qubits. “If you want to make a quantum computing device using these trapped electrons, how do you send information around on the chip? You need the quantum computing equivalent of a wire.”

Silicon spin qubits are more resilient than competing qubit technologies to outside disturbances such as heat and vibrations, which disrupt inherently fragile quantum states. The simple act of reading out the results of a quantum calculation can destroy the quantum state, a phenomenon known as “quantum demolition.”

The researchers theorize that the current approach may avoid this problem because it uses light to probe the state of the quantum system. Light is already used as a messenger to bring cable and internet signals into homes via fiber optic cables, and it is also being used to connect superconducting qubit systems, but this is one of the first applications in silicon spin qubits.

In these qubits, information is represented by the electron’s spin, which can point up or down. For example, a spin pointing up could represent a 0 and a spin pointing down could represent a 1. Conventional computers, in contrast, use the electron’s charge to encode information.

Connecting silicon-based qubits so that they can talk to each other without destroying their information has been a challenge for the field. Although the Princeton-led team successfully coupled two neighboring electron spins separated by only 100 nanometers (100 billionths of a meter), as published in Science in December 2017, coupling spin to light, which would enable long-distance spin-spin coupling, has remained a challenge until now.

In the current study, the team solved the problem of long-distance communication by coupling the qubit’s information — that is, whether the spin points up or down — to a particle of light, or photon, which is trapped above the qubit in the chamber. The photon’s wave-like nature allows it to oscillate above the qubit like an undulating cloud.

Graduate student Xiao Mi and colleagues figured out how to link the information about the spin’s direction to the photon, so that the light can pick up a message, such as “spin points up,” from the qubit. “The strong coupling of a single spin to a single photon is an extraordinarily difficult task akin to a perfectly choreographed dance,” Mi said. “The interaction between the participants — spin, charge and photon — needs to be precisely engineered and protected from environmental noise, which has not been possible until now.” The team at Princeton included postdoctoral fellow Stefan Putz and graduate student David Zajac.

The advance was made possible by tapping into light’s electromagnetic wave properties. Light consists of oscillating electric and magnetic fields, and the researchers succeeded in coupling the light’s electric field to the electron’s spin state.

The researchers did so by building on team’s finding published in December 2016 in the journal Science that demonstrated coupling between a single electron charge and a single particle of light.

To coax the qubit to transmit its spin state to the photon, the researchers place the electron spin in a large magnetic field gradient such that the electron spin has a different orientation depending on which side of the quantum dot it occupies. The magnetic field gradient, combined with the charge coupling demonstrated by the group in 2016, couples the qubit’s spin direction to the photon’s electric field.

Ideally, the photon will then deliver the message to another qubit located within the chamber. Another possibility is that the photon’s message could be carried through wires to a device that reads out the message. The researchers are working on these next steps in the process.

Several steps are still needed before making a silicon-based quantum computer, Petta said. Everyday computers process billions of bits, and although qubits are more computationally powerful, most experts agree that 50 or more qubits are needed to achieve quantum supremacy, where quantum computers would start to outshine their classical counterparts.

Daniel Loss, a professor of physics at the University of Basel in Switzerland who is familiar with the work but not directly involved, said: “The work by Professor Petta and collaborators is one of the most exciting breakthroughs in the field of spin qubits in recent years. I have been following Jason’s work for many years and I’m deeply impressed by the standards he has set for the field, and once again so with this latest experiment to appear in Nature. It is a big milestone in the quest of building a truly powerful quantum computer as it opens up a pathway for cramming hundreds of millions of qubits on a square-inch chip. These are very exciting developments for the field ¬– and beyond.”

A new smart and responsive material can stiffen up like a worked-out muscle, say the Iowa State University engineers who developed it.

Stress a muscle and it gets stronger. Mechanically stress the rubbery material – say with a twist or a bend – and the material automatically stiffens by up to 300 percent, the engineers said. In lab tests, mechanical stresses transformed a flexible strip of the material into a hard composite that can support 50 times its own weight.

Examples of the new smart material, left to right: A flexible strip; a flexible strip that stiffened when twisted; a flexible strip transformed into a hard composite that can hold up a weight. Credit: Christopher Gannon/Iowa State University

Examples of the new smart material, left to right: A flexible strip; a flexible strip that stiffened when twisted; a flexible strip transformed into a hard composite that can hold up a weight. Credit: Christopher Gannon/Iowa State University

This new composite material doesn’t need outside energy sources such as heat, light or electricity to change its properties. And it could be used in a variety of ways, including applications in medicine and industry.

The material is described in a paper recently published online by the scientific journal Materials Horizons. The lead authors are Martin Thuo and Michael Bartlett, Iowa State assistant professors of materials science and engineering. First authors are Boyce Chang and Ravi Tutika, Iowa State doctoral students in materials science and engineering. Chang is also a student associate of the U.S. Department of Energy’s Ames Laboratory.

Iowa State startup funds for Thuo and Bartlett supported development of the new material. Thuo’s Black & Veatch faculty fellowship also helped support the project.

Development of the material combined Thuo’s expertise in micro-sized, liquid-metal particles with Bartlett’s expertise in soft materials such as rubbers, plastics and gels.

It’s a powerful combination.

The researchers found a simple, low-cost way to produce particles of undercooled metal – that’s metal that remains liquid even below its melting temperature. The tiny particles (they’re just 1 to 20 millionths of a meter across) are created by exposing droplets of melted metal to oxygen, creating an oxidation layer that coats the droplets and stops the liquid metal from turning solid. They also found ways to mix the liquid-metal particles with a rubbery elastomer material without breaking the particles.

When this hybrid material is subject to mechanical stresses – pushing, twisting, bending, squeezing – the liquid-metal particles break open. The liquid metal flows out of the oxide shell, fuses together and solidifies.

“You can squeeze these particles just like a balloon,” Thuo said. “When they pop, that’s what makes the metal flow and solidify.”

The result, Bartlett said, is a “metal mesh that forms inside the material.”

Thuo and Bartlett said the popping point can be tuned to make the liquid metal flow after varying amounts of mechanical stress. Tuning could involve changing the metal used, changing the particle sizes or changing the soft material.

In this case, the liquid-metal particles contain Field’s metal, an alloy of bismuth, indium and tin. But Thuo said other metals will work, too.

“The idea is that no matter what metal you can get to undercool, you’ll get the same behavior,” he said.

The engineers say the new material could be used in medicine to support delicate tissues or in industry to protect valuable sensors. There could also be uses in soft and bio-inspired robotics or reconfigurable and wearable electronics. The Iowa State University Research Foundation is working to patent the material and it is available for licensing.

“A device with this material can flex up to a certain amount of load,” Bartlett said. “But if you continue stressing it, the elastomer will stiffen and stop or slow down these forces.”

And that, the engineers say, is how they’re putting some muscle in their new smart material.

 

Engineers at Rutgers University-New Brunswick and Oregon State University are developing a new method of processing nanomaterials that could lead to faster and cheaper manufacturing of flexible thin film devices – from touch screens to window coatings, according to a new study.

The “intense pulsed light sintering” method uses high-energy light over an area nearly 7,000 times larger than a laser to fuse nanomaterials in seconds. Nanomaterials are materials characterized by their tiny size, measured in nanometers. A nanometer is one millionth of a millimeter, or about 100,000 times smaller than the diameter of a human hair.

The existing method of pulsed light fusion uses temperatures of around 250 degrees Celsius (482 degrees Fahrenheit) to fuse silver nanospheres into structures that conduct electricity. But the new study, published in RSC Advances and led by Rutgers School of Engineering doctoral student Michael Dexter, showed that fusion at 150 degrees Celsius (302 degrees Fahrenheit) works well while retaining the conductivity of the fused silver nanomaterials.

The engineers’ achievement started with silver nanomaterials of different shapes: long, thin rods called nanowires in addition to nanospheres. The sharp reduction in temperature needed for fusion makes it possible to use low-cost, temperature-sensitive plastic substrates like polyethylene terephthalate (PET) and polycarbonate in flexible devices, without damaging them.

“Pulsed light sintering of nanomaterials enables really fast manufacturing of flexible devices for economies of scale,” said Rajiv Malhotra, the study’s senior author and assistant professor in the Department of Mechanical and Aerospace Engineering at Rutgers-New Brunswick. “Our innovation extends this capability by allowing cheaper temperature-sensitive substrates to be used.”

Fused silver nanomaterials are used to conduct electricity in devices such as radio-frequency identification (RFID) tags, display devices and solar cells. Flexible forms of these products rely on fusion of conductive nanomaterials on flexible substrates, or platforms, such as plastics and other polymers.

“The next step is to see whether other nanomaterial shapes, including flat flakes and triangles, will drive fusion temperatures even lower,” Malhotra said.

In another study, published in Scientific Reports, the Rutgers and Oregon State engineers demonstrated pulsed light sintering of copper sulfide nanoparticles, a semiconductor, to make films less than 100 nanometers thick.

“We were able to perform this fusion in two to seven seconds compared with the minutes to hours it normally takes now,” said Malhotra, the study’s senior author. “We also showed how to use the pulsed light fusion process to control the electrical and optical properties of the film.”

Their discovery could speed up the manufacturing of copper sulfide thin films used in window coatings that control solar infrared light, transistors and switches, according to the study. This work was funded by the National Science Foundation and The Walmart Manufacturing Innovation Foundation.

Graphene on toast, anyone?


February 13, 2018

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

Rice University graduate student Yieu Chyan, left, and Professor James Tour. Credit: Jeff Fitlow/Rice University

Rice University graduate student Yieu Chyan, left, and Professor James Tour. Credit: Jeff Fitlow/Rice University

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

MagnaChip Semiconductor Corporation (NYSE: MX), a designer and manufacturer of analog and mixed-signal semiconductor platform solutions, announced today it now offers the 2nd generation of 0.13 micron BCD process technology integrated with high-density embedded Flash memory. This second-generation BCD process offers advanced features compared to previous BCD processes, which are high-density Flash memory up to 64 kilo bytes, low specific Ron of power LDMOS up to 40V, low number of photo steps and automotive grade reliability. These characteristics make the new generation of BCD process technology highly suitable for programmable PMICs, wireless power chargers, USB-C power-delivery IC products and automotive power ICs.

Traditionally, the non-volatile memories in the BCD process are low in density, below 256 bytes, for trimming purposes. However, today’s electronic devices require more complex functions and lower power consumption. As a result, there is a greater market need for high-density embedded non-volatile memory in the BCD process. This memory includes Flash memory used for power ICs, including programmable PMICs, wireless power chargers and USB-C power-delivery ICs. In some applications, high-density Flash memory up to 64 kilo bytes is used to store programming codes as well as trimming data. Until now, the drawback of implementing high-density embedded memory in other BCD processes has been that it increases the overall number of manufacturing steps.

MagnaChip was able to eliminate 8 photo steps in the second-generation BCD process from the 1st generation by process optimization. Aside from embedded non-volatile memory, the 2nd generation also achieved the improvement of power LDMOS specific Ron performance, which is well suited for high-power requirements up to 40V operation. For IoT and automotive applications, this BCD process provides 1.5V and 5V CMOS devices with very low leakage current level that enables low power consumption. Furthermore, this new BCD process has various option devices for Hall sensors, varactors, inductors, and RF CMOS devices that are useful for highly integrated IC solutions, which give smaller system size and less system cost.

YJ Kim, Chief Executive Officer of MagnaChip, commented, “The integration of analog-based BCD and high density non-volatile memory enables highly suitable ICs and system designs for power management solutions, wireless chargers and power ICs used in smartphones, IoT devices and automotive applications.” Mr. Kim added, “Our goal is to continue to develop specialized and innovative process technologies that meet the changing market requirements of our foundry customers.”

Imec has designed and fabricated a 16,384-electrode, 1,024-channel micro-electrode array (MEA) for high-throughput multi-modal cell interfacing. The chip offers intracellular and extracellular recording, voltage- and current-controlled stimulation, impedance monitoring and spectroscopy functionalities thereby packing the most cell-interfacing modalities on a single chip, and being the only one to enable multi-well assays. With this new chip, imec has created a platform that enables high quality data acquisition at increased throughput in cell-based cell studies. Imec’s micro-electrode array chip will be presented at ISSCC in San Francisco, Feb. 11-15.

These results will be presented at ISSCC2018 on Feb 14, 2018 in session 29: Advanced Biomedical Systems at 2.30 pm: 29.3 – A 16384-Electrode 1024-Channel Multimodal CMOS MEA for High-Throughput Intracellular Action Potential Measurements and Impedance Spectroscopy in Drug-Screening Applications, C. Mora Lopez et al. (imec).

These results will be presented at ISSCC2018 on Feb 14, 2018 in session 29: Advanced Biomedical Systems at 2.30 pm: 29.3 – A 16384-Electrode 1024-Channel Multimodal CMOS MEA for High-Throughput Intracellular Action Potential Measurements and Impedance Spectroscopy in Drug-Screening Applications, C. Mora Lopez et al. (imec).

MEAs have since long been used for in vitro cell-interaction experiments. However, most of today’s MEAs do not support high throughput measurements, making current cell-assays time-consuming. They are typically passive devices, without built-in circuitry, therefore requiring complex external equipment for data acquisition. Additionally, most MEAs are not able to accommodate the extra sensing modalities to fully characterize complex cell behavior and interactions.

Imec’s high-throughput multi-modal CMOS-MEA packs 16,384 active electrodes with signal processing, filtering and analog-to-digital conversion on-chip, resulting in a very complete and compact system with easy interfacing. To improve the signal quality, each electrode has a miniature pre-amplifier. The electrodes are grouped in 16 clusters, each of which can be addressed individually, making it possible to run 16 experiments independently and simultaneously. This CMOS-MEA also includes 1,024 low-noise readout channels that can be connected to any of the 16,384 electrodes. The custom reconfigurable on-chip circuits support 6 cell-interfacing modalities: both extra- and intracellular electrical activity recording, constant voltage and constant current stimulation for cell excitation or localized electroporation, fast impedance monitoring and, finally, impedance spectroscopy. While fast impedance monitoring can detect impedance changes over time and cell presence for optimal electrode selection, single-cell impedance spectroscopy gives detailed information of the electrode impedance, seal resistance and cell-membrane impedance which can be used for cell differentiation. Imec’s high input impedance, low noise and low power reconfigurable circuits make it possible to integrate 1,024 parallel readout channels and 64 reconfigurable stimulation units on a small chip area.

“Not only are we reporting the highest number of modalities so far on a single chip with a very high channel count, we are able to achieve this without any performance penalty. Moreover, by offering six modalities on such large scale, the imec CMOS-MEA will greatly improve the throughput and versatility of cell-based assays,” commented Nick Van Helleputte, manager biomedical circuits at imec. “With the introduction of CMOS chip technology into the MEA-technology, we have realized a breakthrough in cell interfacing.”

NUST MISIS scientists jointly with an international group of scientists have managed to develop a composite material that has the best piezoelectric properties today. The research results were published in Scientific Reports journal.

Topography (a), PFM images of a pristine state (b) and after poling by +/?60V (c). Credit: ©NUST MISIS

Topography (a), PFM images of a pristine state (b) and after poling by +/?60V (c). Credit: ©NUST MISIS

Piezoelectrics are one of the world`s most amazing materials. It is possible to literally squeeze electricity from them. That is, an electric charge appears at the time of the material`s compression (or stretching). This is called the piezoelectric effect. Piezoelectric materials can be applied in many fields – from pressure sensors and sensitive elements of a microphone to the controller ink pressing in ink-jet printers and quartz resonators.

Lead zirconate titanate is one of the most popular piezoelectric materials. However, it has several disadvantages: it is heavy and inflexible. Additionally, lead production often causes great harm to the environment. That is why scientists are constantly looking for new materials with low lead content as well as with less weight and greater flexibility. In particular, the creation of flexible piezoelectric materials (while maintaining the key properties) would greatly expand piezoelectric materials` possibilities both as acoustic membrane and as pressure sensors.

An international team of scientists from the University of Duisburg-Essen (Germany), NUST MISIS, National Research Tomsk State University and the National Research University of Electronic Technology, working with the financial support of the Russian Science Foundation (grant 16-19-10112), has managed to create such a material and analyze its properties. For this, the nanoparticles consisting of titanate-zicronate barium-lead were placed in a complex polymer consisting of vinylidene disluoride and trifluoroethylene. By diversifying the composition of the components, scientists were able to get the most ideal composite.

The Russian-German group of scientists, including Dmitri Kiselev, a Senior Researcher at the NUST MISIS R&D Center for Materials Science & Metallurgy, has managed to create a composite material based on ceramics and organic polymer whose properties exceed today`s best piezoelectric materials. The research’s experimental part was carried out with an atomic-force microscope in the University of Duisburg-Essen (Germany). Thanks to this scientific collaboration, Dmitri Kiselev has gained skills from the world`s best scanning probe microscope, which he can later apply at NUST MISIS», said Alevtina Chernikova, Rector of NUST MISIS.

According to Dmitri Kiselev, the developed material has a very distinct field of application due to its polymer component: «Composite materials based on polymer and classic ferroelectrics, which have piezo- and pyroelectric properties, have a number of advantages compared to pure ceramics: low density, the ability to manufacture parts of any size and shape, mechanical elasticity, stability of electrophysical properties, and the simplicity and relatively low cost of production. Additionally, the synthesized composite has proved to be excellent at high pressures which makes it an excellent base for pressure sensors».

According to Kiselev, to study the composite they had to modify the standard technique which allowed them to correctly visualize the nanoparticles of ceramics in the volume of the polymer matrix: «In order to capture the electrical signal more clearly, we heated our sample in a certain way from room temperature to 60 degrees Celsius. It allowed us to measure the material’s characteristics very qualitatively and reproducibly. Our method will greatly simplify the work of our colleagues in the study of composites, so I hope that it will be in demand among our colleagues microscopists».

«It is now easier for Russian scientists to carry out world-class measurements as the MFP 3D Stand ?lone (Asylum Research) microscope is now available at the NUST MISIS Center for Collaborative Use, hence why we are now actively collaborating with several institutes from the Russian Academy of Sciences as well as other Moscow universities», Kiselev concluded.

 

Brooks Instrument will showcase its newly enhanced GF125 mass flow controller (MFC) with high-speed EtherCAT connectivity and embedded self-diagnostics at the China Semiconductor Technology International Conference (CSTIC) in conjunction with SEMICON China 2018 in Shanghai.

CSTIC runs March 11-12 at the Shanghai International Convention Center, while SEMICON China takes place March 14-16 at the Shanghai New International Expo Center.

Building on the company’s proven GF Series of MFCs with EtherCAT connectivity for high-speed communications, the newly enhanced GF125 MFC features embedded self-diagnostics that automatically detect sensor drift and valve leak-by to help minimize tool downtime and improve process yield. As a result, the enhanced GF125 can run leak and drift self-diagnostics without interrupting process flow steps or requiring any hardware changes, thereby improving process gas accuracy and wafer production throughput.

Technology experts from Brooks Instrument will discuss the newly enhanced GF125 MFC capabilities with a presentation on “Advanced Mass Flow Controllers With EtherCAT Communication Protocol and Embedded Self-Diagnostics” during the CSTIC poster session.

For SEMICON China, Brooks Instrument will be co-exhibiting in booth 3675 with its regional business partner, SCH Electronics Co., Ltd., to demonstrate the newly enhanced GF125 MFC with high-speed EtherCAT connectivity and embedded self-diagnostics, along with a broad range of other mass flow meters and controllers and pressure and vacuum products for semiconductor manufacturing.

“At Brooks Instrument, we’re eager to present and exhibit at the China Semiconductor Technology International Conference and SEMICON China tradeshow,” said Mohamed Saleem, Chief Technology Officer at Brooks Instrument. “With more than 70 years of history in new technology developments, our company is focused on improving the precision and performance of mass flow, pressure and vacuum technologies to help enable advanced semiconductor manufacturing and address the challenges involved with next-generation production tools and processes.”

In addition to the newly enhanced GF125 MFC with high-speed EtherCAT connectivity and embedded self-diagnostics, Brooks Instrument will showcase other key components designed to meet critical gas chemistry control challenges and improve process yields for nodes 10nm and below, including the VDM300 vapor delivery module as well as other proven MFCs with EtherCAT.