Category Archives: Materials

Cheap, flexible and sustainable plastic semiconductors will soon be a reality thanks to a breakthrough by chemists at the University of Waterloo.

Professor Derek Schipper and his team at Waterloo have developed a way to make conjugated polymers, plastics that conduct electricity like metals, using a simple dehydration reaction the only byproduct of which is water.

“Nature has been using this reaction for billions of years and industry more than a hundred,” said Schipper, a professor of Chemistry and a Canada Research Chair in Organic Material Synthesis. “It’s one of the cheapest and most environmentally friendly reactions for producing plastics.”

Schipper and his team have successfully applied this reaction to create poly(hetero)arenes, one of the most studied classes of conjugated polymers which have been used to make lightweight, low- cost electronics such as solar cells, LED displays, and chemical and biochemical sensors.

Dehydration is a common method to make polymers, a chain of repeating molecules or monomers that link up like a train. Nature uses the dehydration reaction to make complex sugars from glucose, as well as proteins and other biological building blocks such as cellulose. Plastics manufacturers use it to make everything from nylon to polyester, cheaply and in mind-boggling bulk.

“Synthesis has been a long-standing problem in this field,” said Schipper. “A dehydration method such as ours will streamline the entire process from discovery of new derivatives to commercial product development. Better still, the reaction proceeds relatively fast and at room temperature.”

Conjugated polymers were first discovered by Alan Heeger, Alan McDonald, and Hideki Shirakawa in the late 1970s, eventually earning them the Nobel Prize in Chemistry in 2000.

Researchers and engineers quickly discovered several new polymer classes with plenty of commercial applications, including a semiconducting version of the material; but progress has stalled in reaching markets in large part because conjugated polymers are so hard to make. The multi-step reactions often involve expensive catalysts and produce environmentally harmful waste products.

Schipper and his team are continuing to perfect the technique while also working on developing dehydration synthesis methods for other classes of conjugated polymers. The results of their research so far appeared recently in the journal Chemistry – A European Journal.

 

By Walt Custer, Custer Consulting Group

Global Manufacturing Growth has Slowed, but is Still Positive (Chart 1)

Most key countries/regions saw a slowdown in growth in March based on their respective Purchasing Managers Indices. And in one case – South Korea – manufacturing moved into contraction.

February 2018 March 2018
Japan 54.1 53.1
South Korea 50.3 49.1
Taiwan 56.0 55.3
China 51.6 51.0
Europe 58.6 56.6
USA 60.8 59.3

custer-1-424

PMI Points to More Modest Expansion (Chart 2)

The global Purchasing Managers Index is a timely and readily available leading indicator for both world semiconductor and semiconductor capital equipment shipments. PMI values greater than 50 indicate expanding manufacturing activity.  See www.markiteconomics.com for PMI values for all major countries.

 

Recent semiconductor equipment, semiconductor and PMI 3-month (3/12) world growth rates were:

SEMI Equipment +29% February
Semiconductors                +21% February
PMI (squared) +4% March

The PMI leading indicator now points to more modest but still positive growth ahead.

custer-2-424

Semiconductor Industry Still has Legs (Chart 3)

Another useful and timely leading indicator is a composite of monthly Taiwan Chip Foundry sales.  Taiwan-listed companies publish their revenues about 10 days after the month closes. Chart 3 compares the composite monthly revenues of 14 Taiwan listed foundries vs. global semiconductor sales. Due to Lunar New year shutdowns, February 2018 was weak but foundry sales rebounded in March. Chip demand appears to be holding!

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Originally published on the SEMI blog.

The next generation of energy-efficient power electronics, high-frequency communication systems, and solid-state lighting rely on materials known as wide bandgap semiconductors. Circuits based on these materials can operate at much higher power densities and with lower power losses than silicon-based circuits. These materials have enabled a revolution in LED lighting, which led to the 2014 Nobel Prize in physics.

In new experiments reported in Applied Physics Letters, from AIP Publishing, researchers have shown that a wide-bandgap semiconductor called gallium oxide (Ga2O3) can be engineered into nanometer-scale structures that allow electrons to move much faster within the crystal structure. With electrons that move with such ease, Ga2O3 could be a promising material for applications such as high-frequency communication systems and energy-efficient power electronics.

Schematic stack and the scanning electron microscopic image of the β-(AlxGa1-x)2O3/Ga2O3 modulation-doped field effect transistor. Credit: Choong Hee Lee and Yuewei Zhang

Schematic stack and the scanning electron microscopic image of the β-(AlxGa1-x)2O3/Ga2O3 modulation-doped field effect transistor. Credit: Choong Hee Lee and Yuewei Zhang

“Gallium oxide has the potential to enable transistors that would surpass current technology,” said Siddharth Rajan of Ohio State University, who led the research.

Because Ga2O3 has one of the largest bandgaps (the energy needed to excite an electron so that it’s conductive) of the wide bandgap materials being developed as alternatives to silicon, it’s especially useful for high-power and high-frequency devices. It’s also unique among wide bandgap semiconductors in that it can be produced directly from its molten form, which enables large-scale manufacturing of high-quality crystals.

For use in electronic devices, the electrons in the material must be able to move easily under an electric field, a property called high electron mobility. “That’s a key parameter for any device,” Rajan said. Normally, to populate a semiconductor with electrons, the material is doped with other elements. The problem, however, is that the dopants also scatter electrons, limiting the electron mobility of the material.

To solve this problem, the researchers used a technique known as modulation doping. The approach was first developed in 1979 by Takashi Mimura to create a gallium arsenide high-electron mobility transistor, which won the Kyoto Prize in 2017. While it is now a commonly used technique to achieve high mobility, its application to Ga2O3 is something new.

In their work, the researchers created a so-called semiconductor heterostructure, creating an atomically perfect interface between Ga2O3 and its alloy with aluminum, aluminum gallium oxide — two semiconductors with the same crystal structure but different energy gaps. A few nanometers away from the interface, embedded inside the aluminum gallium oxide, is a sheet of electron-donating impurities only a few atoms thick. The donated electrons transfer into the Ga2O3, forming a 2-D electron gas. But because the electrons are now also separated from the dopants (hence the term modulation doping) in the aluminum gallium oxide by a few nanometers, they scatter much less and remain highly mobile.

Using this technique, the researchers reached record mobilities. The researchers were also able to observe Shubnikov-de Haas oscillations, a quantum phenomenon in which increasing the strength of an external magnetic field causes the resistance of the material to oscillate. These oscillations confirm formation of the high mobility 2-D electron gas and allow the researchers to measure critical material properties.

Rajan explained that such modulation-doped structures could lead to a new class of quantum structures and electronics that harnesses the potential of Ga2O3.

SEMI, the global industry association representing the electronics manufacturing supply chain, today announced that in 2017 the global semiconductor materials market grew 9.6 percent while worldwide semiconductor revenues increased 21.6 percent from the prior year.

According to the SEMI Materials Market Data Subscription, total wafer fabrication materials and packaging materials totaled $27.8 billion and $19.1* billion, respectively, in 2017. In 2016, the wafer fabrication materials and packaging materials markets logged revenues of $24.7 billion and $18.2 billion, respectively, for 12.7 percent and 5.4 percent year-over-year increases.

For the eighth consecutive year, Taiwan, at $10.3 billion, was the largest consumer of semiconductor materials due to its large foundry and advanced packaging base. China solidified its hold on the second spot, followed by South Korea and Japan. The Taiwan, China, Europe and South Korea markets saw the strongest revenue growth, while the North America, Rest of World (ROW) and Japan materials markets experienced moderate single-digit growth. (The ROW region is defined as Singapore, Malaysia, Philippines, other areas of Southeast Asia and smaller global markets.)

2016 and 2017 Regional Semiconductor Materials Markets (US$ Billions)

Region
2016**
2017
% Change
Taiwan
9.20
10.29
12%
China
6.80
7.62
12%
South Korea
6.77
7.51
11%
Japan
6.76
7.05
4%
Rest of World
5.39
5.81
8%
North America
4.87
5.29
9%
Europe
3.03
3.36
11%
Total
42.82
46.93
10%

Source: SEMI, April 2018

Note: Summed subtotals may not equal the total due to rounding.

* Includes ceramic packages and flexible substrates

** 2016 data have been updated based on SEMI’s data collection programs

The Materials Market Data Subscription (MMDS) from SEMI provides current revenue data along with seven years of historical data and a two-year forecast. The annual subscription includes four quarterly updates for the materials segment reports revenue for seven market regions (North America, Europe, ROW, Japan, Taiwan, South Korea, and China).

In a recent study published in Science, researchers at ICFO – The Institute of Photonic Sciences in Barcelona, Spain, along with other members of the Graphene Flagship, reached the ultimate level of light confinement. They have been able to confine light down to a space one atom, the smallest possible. This will pave the way to ultra-small optical switches, detectors and sensors.

Light can function as an ultra-fast communication channel, for example between different sections of a computer chip, but it can also be used for ultra-sensitive sensors or on-chip nanoscale lasers. There is currently much research into how to further shrink devices that control and guide light.

New techniques searching for ways to confine light into extremely tiny spaces, much smaller than current ones, have been on the rise. Researchers had previously found that metals can compress light below the wavelength-scale (diffraction limit), but more confinement would always come at the cost of more energy loss. This fundamental issue has now been overcome.

“Graphene keeps surprising us: nobody thought that confining light to the one-atom limit would be possible. It will open a completely new set of applications, such as optical communications and sensing at a scale below one nanometer,” said ICREA Professor Frank Koppens at ICFO – The Institute of Photonic Sciences in Barcelona, Spain, who led the research.

This team of researchers including those from ICFO (Spain), University of Minho (Portugal) and MIT (USA) used stacks of two-dimensional materials, called heterostructures, to build up a new nano-optical device. They took a graphene monolayer (which acts as a semi-metal), and stacked onto it a hexagonal boron nitride (hBN) monolayer (an insulator), and on top of this deposited an array of metallic rods. They used graphene because it can guide light in the form of plasmons, which are oscillations of the electrons, interacting strongly with light.

“At first we were looking for a new way to excite graphene plasmons. On the way, we found that the confinement was stronger than before and the additional losses minimal. So we decided to go to the one atom limit with surprising results,” said David Alcaraz Iranzo, the lead author from ICFO.

By sending infra-red light through their devices, the researchers observed how the plasmons propagated in between the metal and the graphene. To reach the smallest space conceivable, they decided to reduce the gap between the metal and graphene as much as possible to see if the confinement of light remained efficient, i.e. without additional energy losses. Strikingly, they saw that even when a monolayer of hBN was used as a spacer, the plasmons were still excited, and could propagate freely while being confined to a channel of just one atom thick. They managed to switch this plasmon propagation on and off, simply by applying an electrical voltage, demonstrating the control of light guided in channels smaller than one nanometer.

This enables new opto-electronic devices that are just one nanometer thick, such as ultra-small optical switches, detectors and sensors. Due to the paradigm shift in optical field confinement, extreme light-matter interactions can now be explored that were not accessible before. The atom-scale toolbox of two-dimensional materials has now also proven applicable for many types of new devices where both light and electrons can be controlled even down to the scale of a nanometer.

Professor Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship, and Chair of its Management Panel, added “While the flagship is driving the development of novel applications, in particular in the field of photonics and optoelectronics, we do not lose sight of fundamental research. The impressive results reported in this paper are a testimony to the relevance for cutting edge science of the Flagship work. Having reached the ultimate limit of light confinement could lead to new devices with unprecedented small dimensions.”

Versum Materials, Inc. (NYSE: VSM), a materials supplier to the semiconductor industry, announced today the grand opening of its new research and development (R&D) facility at its semiconductor materials manufacturing site in Hometown, Pennsylvania. The ribbon-cutting ceremony took place April 10, 2018. Versum employees, members of the community, local government, customers and strategic partners attended the event.

The R&D laboratory is dedicated to new materials used in the manufacture of semiconductors. Scientists in the facility will synthesize and purify new molecules down to parts per billion impurity levels and below using the latest technologies available in the industry. The researchers can assess the applications for these new molecules and scale up the molecules to larger quantities for customer evaluation. These new organometallic compounds will be deposited on semiconductor wafers through cutting-edge technologies to test their performance for semiconductor applications. Additionally, the facility is capable of small-volume manufacturing and advanced analytical and quality assessment.

State Senator Dave Argall commended Versum for being the region’s third largest employer and for the company’s investments in the local community. Approximately 30 employees, half of which hold advanced degrees in chemistry or chemical engineering, are based in the new facility. The company’s Hometown campus now totals 250 highly-skilled employees.

The latest expansion is part of a $60MM multi-year investment in the Hometown campus. Last year the company announced it had increased production capacity and modified equipment configuration to reduce manufacturing bottlenecking. Versum’s Hometown manufacturing facility produces a variety of high purity specialty gases and chemicals for semiconductor manufacturers around the world, including Tungsten Hexafluoride, WF6 and Nitrogen Trifluoride, NF3. WF6 is used as a metallization source for the formation of tungsten interconnects between multiple layers in semiconductor devices. It is an important material in the production of both logic and memory (DRAM and NAND) devices. NF3 is primarily used for chamber cleaning of chemical vapor deposition reactors.

Versum’s Senior Vice President of Materials, Ed Shober addressed the attendees stating, “We enable the largest tech companies around the world to stretch the boundaries of science and technology, whether it be supporting computing power, mobility, connectivity, artificial intelligence, virtual/augmented reality, the Internet of Things, Big Data and machine learning. Versum Materials is at the core of enabling all these technologies. Our Versum Materials team delivers valued products and solutions that bring this cutting-edge innovation to the market safer, faster, easier and more reliably than ever before.”

A current area of intense interest in nanotechnology is van der Waals heterostructures, which are assemblies of atomically thin two-dimensional (2D) crystalline materials that display attractive conduction properties for use in advanced electronic devices.

A representative 2D semiconductor is graphene, which consists of a honeycomb lattice of carbon atoms that is just one atom thick. The development of van der Waals heterostructures has been restricted by the complicated and time-consuming manual operations required to produce them. That is, the 2D crystals typically obtained by exfoliation of a bulk material need to be manually identified, collected, and then stacked by a researcher to form a van der Waals heterostructure. Such a manual process is clearly unsuitable for industrial production of electronic devices containing van der Waals heterostructures

Now, a Japanese research team led by the Institute of Industrial Science at The University of Tokyo has solved this issue by developing an automated robot that greatly speeds up the collection of 2D crystals and their assembly to form van der Waals heterostructures. The robot consists of an automated high-speed optical microscope that detects crystals, the positions and parameters of which are then recorded in a computer database. Customized software is used to design heterostructures using the information in the database. The heterostructure is then assembled layer by layer by a robotic equipment directed by the designed computer algorithm. The findings were reported in Nature Communications.

Robot developed for automated assembly of designer nanomaterials. Credit: 2018 SATORU MASUBUCHI, INSTITUTE OF INDUSTRIAL SCIENCE, THE UNIVERSITY OF TOKYO

Robot developed for automated assembly of designer nanomaterials. Credit: 2018 SATORU MASUBUCHI, INSTITUTE OF INDUSTRIAL SCIENCE, THE UNIVERSITY OF TOKYO

“The robot can find, collect, and assemble 2D crystals in a glove box,” study first author Satoru Masubuchi says. “It can detect 400 graphene flakes an hour, which is much faster than the rate achieved by manual operations.”

When the robot was used to assemble graphene flakes into van der Waals heterostructures, it could stack up to four layers an hour with just a few minutes of human input required for each layer. The robot was used to produce a van der Waals heterostructure consisting of 29 alternating layers of graphene and hexagonal boron nitride (another common 2D semiconductor). The record layer number of a van der Waals heterostructure produced by manual operations is 13, so the robot has greatly increased our ability to access complex van der Waals heterostructures.

“A wide range of materials can be collected and assembled using our robot,” co-author Tomoki Machida explains. “This system provides the potential to fully explore van der Waals heterostructures.”

The development of this robot will greatly facilitate production of van der Waals heterostructures and their use in electronic devices, taking us a step closer to realizing devices containing atomic-level designer materials.

Physicists at the University of Warwick have today, Thursday 19th April 2018, published new research in the fournal Science today 19th April 2018 (via the Journal’s First Release pages) that could literally squeeze more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells.

This is an artists impression of squeezing more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. Credit: University of Warwick/Mark Garlick

This is an artists impression of squeezing more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. Credit: University of Warwick/Mark Garlick

The paper entitled the “Flexo-Photovoltaic Effect” was written by Professor Marin Alexe, Ming-Min Yang, and Dong Jik Kim who are all based in the University of Warwick’s Department of Physics.

The Warwick researchers looked at the physical constraints on the current design of most commercial solar cells which place an absolute limit on their efficiency. Most commercial solar cells are formed of two layers creating at their boundary a junction between two kinds of semiconductors, p-type with positive charge carriers (holes which can be filled by electrons) and n-type with negative charge carriers (electrons).

When light is absorbed, the junction of the two semiconductors sustains an internal field splitting the photo-excited carriers in opposite directions, generating a current and voltage across the junction. Without such junctions the energy cannot be harvested and the photo-exited carriers will simply quickly recombine eliminating any electrical charge.

That junction between the two semiconductors is fundamental to getting power out of such a solar cell but it comes with an efficiency limit. This Shockley-Queisser Limit means that of all the power contained in sunlight falling on an ideal solar cell in ideal conditions only a maximum of 33.7% can ever be turned into electricity.

There is however another way that some materials can collect charges produced by the photons of the sun or from elsewhere. The bulk photovoltaic effect occurs in certain semiconductors and insulators where their lack of perfect symmetry around their central point (their non-centrosymmetric structure) allows generation of voltage that can be actually larger than the band gap of that material (the band gap being the gap between the valence band highest range of electron energies in which electrons are normally present at absolute zero temperature and the conduction band where electricity can flow).

Unfortunately the materials that are known to exhibit the anomalous photovoltaic effect have very low power generation efficiencies, and are never used in practical power-generation systems.

The Warwick team wondered if it was possible to take the semiconductors that are effective in commercial solar cells and manipulate or push them in some way so that they too could be forced into a non-centrosymmetric structure and possibly therefore also benefit from the bulk photovoltaic effect.

For this paper they decided to try literally pushing such semiconductors into shape using conductive tips from atomic force microscopy devices to a “nano-indenter” which they then used to squeeze and deform individual crystals of Strontium Titanate (SrTiO3), Titanium Dioxide (TiO2), and Silicon (Si).

They found that all three could be deformed in this way to also give them a non-centrosymmetric structure and that they were indeed then able to give the bulk photovoltaic effect.

Professor Marin Alexe from the University of Warwick said:

“Extending the range of materials that can benefit from the bulk photovoltaic effect has several advantages: it is not necessary to form any kind of junction; any semiconductor with better light absorption can be selected for solar cells, and finally, the ultimate thermodynamic limit of the power conversion efficiency, so-called Shockley-Queisser Limit, can be overcome. There are engineering challenges but it should be possible to create solar cells where a field of simple glass based tips (a hundred million per cm2) could be held in tension to sufficiently de-form each semiconductor crystal. If such future engineering could add even a single percentage point of efficiency it would be of immense commercial value to solar cell manufacturers and power suppliers.”

Collaborative research team of Prof. Jun Takeda and Associate Prof. Ikufumi Katayama in the laboratory of Yokohama National University (YNU) and Nippon Telegraph and Telephone (NTT) successfully observed petahertz (PHz: 1015of a hertz) electron oscillation. The periodic electron oscillations of 667-383 attoseconds (as: 10-18 of a second) is the fastest that has ever been measured in the direct time-dependent spectroscopy in solid-state material.

NIR femtosecond pulse (pump pulse) induces the electron oscillation, which is monitored by the extreme ultraviolet IAP (probe pulse) based on the transient absorption spectroscopy. Credit: Nippon Telegraph and Telephone (NTT)

NIR femtosecond pulse (pump pulse) induces the electron oscillation, which is monitored by the extreme ultraviolet IAP (probe pulse) based on the transient absorption spectroscopy. Credit: Nippon Telegraph and Telephone (NTT)

As high-speed shutter cameras capture motions of fast-moving objects, researchers generally use laser (pulse) like instantaneous strobe light in order to observe the ultrafast motion of an electron underlying a physical phenomenon. The shorter the pulse duration, the faster the electron oscillation can be observed. The frequency of the lightwave-field in the visible and ultraviolet region can reach the petahertz (PHz: 1015 of a hertz), which means that the oscillation periodicity can achieve attosecond (as: 10-18 of a second) duration.

In previous studies, NTT researchers of the team generated an isolated attosecond pulse (IAP) [H. Mashiko et al., Nature commun. 5, 5599 (2014)] and monitored the electron oscillation with 1.2-PHz frequency using gallium-nitride (GaN) semiconductor [H. Mashiko et al., Nature Phys. 5, 741 (2016)]. The next challenges are the observation of faster electron oscillation in the chromium doped sapphire (Cr:Al2O3) insulator and the characterization of the ultrafast electron dephasing.

The paper, published in the journal Nature communications reports a successful observation of the near-infrared (NIR) pulse-induced multiple electronic dipole oscillations (periodicities of 667-383 as) in the Cr:Al2O3 solid-state material. The measurement is realized by the extreme short IAP (192-as duration) and the use of stable pump (NIR pulse) and probe (IAP) system (timing jitter of ~23 as). The characterized electron oscillations are the fastest that has ever been measured in the direct time-dependent spectroscopy. In addition, the individual dephasing times in the Cr donor-like intermediate level and the Al2O3 CB state are revealed.

Dr. Hiroki Mashiko, a NTT scientist of the team, said, “We contrived the robust pump-probe system with an extremely short isolated attosecond pulse, which led to the observation of the fastest electron oscillation in solid-state material in recorded history. The benefits of this study are directly related to the control of various optical phenomena through the dielectric polarization, and the results will help the development of future electronic and photonic devices.”

Over the past decades, computers have become faster and faster and hard disks and storage chips have reached enormous capacities. But this trend cannot continue forever: we are already running up against physical limits that will prevent silicon-based computer technology from attaining any impressive speed gains from this point on. Researchers are particularly optimistic that the next era of technological advancements will start with the development of novel information-processing materials and technologies that combine electrical circuits with optical ones. Using short laser pulses, a research team led by Misha Ivanov of the Max Born Institute in Berlin together with scientists from the Russian Quantum Center in Moscow have now shed light on the extremely rapid processes taking place within these novel materials. Their results have appeared in the prestigious journal Nature Photonics.

Of particular interest for modern material research in solid state physics are “strongly correlated systems”, so called for the strong interactions between the electrons in these materials. Magnets are a good example of this: the electrons in magnets align themselves in a preferred direction of spin inside the material, and it is this that produces the magnetic field. But there are other, entirely different structural orders that deserve attention. In so-called Mott insulators for example, a class of materials now being intensively researched, the electrons ought to flow freely and the materials should therefore be able to conduct electricity as well as metals. But the mutual interaction between electrons in these strongly correlated materials impedes their flow and so the materials behave as insulators instead.

By disrupting this order with a strong laser pulse, the physical properties can be made to change dramatically. This can be likened to a phase transition from solid to liquid: as ice melts, for example, rigid ice crystals transform into free-flowing water molecules. Very similarly, the electrons in a strongly correlated material become free to flow when an external laser pulse forces a phase transition in their structural order. Such phase transitions should allow us to develop entirely new switching elements for next-generation electronics that are faster and potentially more energy efficient than present-day transistors. In theory, computers could be made around a thousand times faster by “turbo-charging” their electrical components with light pulses.

The problem with studying these phase transitions is that they are extremely fast and it is therefore very difficult to “catch them in the act”. So far, scientists have had to content themselves with characterising the state of a material before and after a phase transition of this kind. Researchers Rui E. F. Silva, Olga Smirnova, and Misha Ivanov of the Berlin Max Born Institute, however, have now devised a method that will, in the truest sense, shed light on the process. Their theory involves firing extremely short, tailored laser pulses at a material – pulses that can only recently be produced in the appropriate quality given the latest developments in lasers. One then observes the material’s reaction to these pulses to see how the electrons in the material are excited into motion and, like a bell, emit resonant vibrations at specific frequencies, as harmonics of the incident light.

“By analysing this high harmonic spectrum, we can observe the change in the structural order in these strongly correlated materials ‘live’ for the first time,” says first author of the paper Rui Silva of the Max Born Institute. Laser sources capable of targetedly triggering these transitions have only been available since very recently. The laser pulses namely have to be amply strong and extremely short – on the order of femtoseconds in duration (millionths of a billionth of a second).

In some cases, it takes only a single oscillation of light to disrupt the electronic order of a material and turn an insulator into a metal-like conductor. The scientists at the Berlin Max Born Institute are among the world’s leading experts in the field of ultrashort laser pulses.

“If we want to use light to control the properties of electrons in a material, then we need to know exactly how the electrons will react to light pulses,” Ivanov explains. With the latest-generation laser sources, which allow full control over the electromagnetic field even down to a single oscillation, the newly published method will allow deep insights into the materials of the future.