Category Archives: Applications

By James Hayward, Technology Analyst, IDTechEx

Last week, IDTechEx gave the opening presentation at the 2016 Korea Summit for Smart Wearable Devices, excellently hosted by KDIA and KSA in Seoul, Korea. Wearable sensors once again dominated discussion throughout the day, with latest examples of options in MEMS, textiles and more presented at length in the conference. Additional discussions throughout the day extended to topics like glucose sensing (including enzyme-free examples), sensor fusion and beyond.

Sensor development is driving the next generation of wearable devices, and this development is now going further than simply attaching sensors to devices that can be stuck on the body. Professor Mark Allen of the University of Pennsylvania gave a fascinating presentation about development of advanced MEMS for wearable devices. MEMS remains the dominant force in wearable sensing, but examples are now becoming broader than the increasingly commoditized, off-the-shelf and near ubiquitous IMU. IDTechExResearch’s bestselling report on the topic, “Wearable Sensors 2016-2026: Market Forecasts, Technologies, Players” finds that IMUs continue to dominate the wearable sensing space, counting for almost half of the total wearable sensor shipments in 2016.

The majority of wearable sensors today are found placed on the body within devices. One step further involves inserting sensors more permanently, whether via something like a skin patch that can be worn for weeks or months at a time, or to use Professor Allen’s example from work at Georgia Tech, magnetometers to detect motion of a magnetic stud inserted as a tongue piercing. Here, the use case is to enable patients suffering significant paralysis to other areas of the body to control an electric wheelchair using the tongue. The next step is to ingest sensors – Proteus Digital Health provide perhaps the most popularized example here, but devices like pill cameras are also regularly used in the diagnostic and clinical trial settings. The next steps involve the full implantation of a sensor, either permanently or through a planned lifetime followed by degradation.

Professor Allen spoke of some of their recently FDA approved work towards implantable sensors for intra cardiac pressure sensing. By fabricating a MEMS devices using ceramics, they created a biologically stable sensor that can be inserted inside the heart in high-risk patients to enable predictive diagnosis and treatment of heart disease. With the group prolifically producing new work, one area is looking at using a core-shell structure to make biodegradable sensors that can maintain structure and communication for a useful lifetime before dissolving. Sensor development is constantly improving the value proposition in many wearable and implantable products, producing state-of-the-art products for the medical space in particular.

IDTechEx Research covers all of the main types of wearable sensors found in products today, as well as sensors of the future in their report “Wearable Sensors 2016-2026: Market Forecasts, Technologies, Players“. The report groups sensors in prominent categories. For each sensor, the technologies and major players are described, backed up by detailed interviews and company profiles of key bodies in each sector. The report also views the big picture, discussing the implications of sensor fusion and the relative merits of each sensor type for various applications. This extensive primary research is used to produce detailed market forecasts for each sensor type over the next decade. Market data is provided for the growth of each sensor type, and is used to illustrate key trends that are observable in various application sectors.

sensors

According to their latest report, Technavio analysts expect the global piezoelectric smart materials market for 2016-2020 to exceed USD 42 billion by 2020 growing at a CAGR of almost 13 percent.

According to Chandrakumar Badala Jaganathan, lead research analyst at Technavio for metals and minerals, “The global piezoelectric smart materials market is expected to be vibrant during the forecast period due to increasing investment in R&D for product innovation and the rising demand from the automotive industry. In addition, high demand from APAC is expected to further drive market growth.”

Technavio’s lead chemicals and materials market research analysts have identified the following three factors that will drive the global piezoelectric smart materials market:

-Increase in demand from military and aerospace sector
-Growing demand from construction industry
-Rise in R&D efforts

Increase in demand from military and aerospace sector

The spacecraft industry has provided a tremendous boost to the piezoelectric smart materials market globally. Materials with enhanced functional properties such as shape memory, electrochromism, and piezoelectricity, are gaining demand in the aerospace industries. These materials help in controlling the airflow across the wings of an aircraft, maintaining it in takeoff, flying, and landing it more efficiently with less noise.

Some applications for aircraft include wing morphing and flapping wing technologies. These materials are used to solve some common problems with the aircraft such as engine vibration, high cabin noise levels, ice formation on wings, flow separation due to turbulence, and control surfaces in cold climatic conditions.

In the military, piezoelectric materials are used in applications such as smart sensors, smart nanorobotics, smart combat suits, and smart skins. The majority of the demand from aerospace industry is expected to come from the US followed by Europe.

Growing demand from construction industry

The application of piezoelectric smart materials in the construction industry falls into three categories: structural health monitoring, vibration control, and environmental control. Structural health monitoring is where piezoelectric smart materials find their most widespread applications. The primary focus of structural health monitoring lies in the monitoring of loads and detection of damage in the structures. In addition, the trend toward longer and more slender cables has given rise to the demand for piezoelectric smart materials for use in structural monitoring and vibration control.

North America has the highest level of activity involving structural health monitoring. In the US, optical fiber grating systems are used to monitor traffic and composite repair monitoring. Additionally, embedded and surface-mounted MEMS sensors are used to monitor concrete and metal structures. “The growing construction sector will lead to a greater demand for piezoelectric smart materials,” says Chandrakumar.

Rise in R&D efforts

Transportation, healthcare, and smart packaging are among the sectors that have been receiving tremendous attention with respect to R&D. In the transportation sector, the military and aerospace sector, followed by the automotive and marine sectors account for the major R&D.

In the US, a considerable amount of funding has been offered by organizations such as the Naval Research Laboratory, Army Research Laboratories, Air Force Research Laboratories, and National Aeronautics and Space Administration. A lot of this funding has been offered to the universities that have given rise to a lot of startup organizations in the field of smart materials.

In Europe, many similar initiatives involving Central European Chapter funded plans. In addition, defense programs, financed by the Western European Union, and a few of the large aerospace companies, are being undertaken by many institutions.

Technavio is a technology research and advisory company.

Leti, an Institute of CEA Tech, and ARaymondlife, a manufacturer of customized devices and consumables for the IVD industry today announced a joint initiative to accelerate the development and manufacturing of innovative medical devices, especially in the field of microfluidic cartridge analysis.

The initiative, based on experiences from ongoing projects, will focus on cartridges that enclose portable bio-med systems that enable sample analysis where the patient is dramatically reducing both the time to see the results and the cost of an analysis.

More broadly, Leti and ARaymondlife will collaborate on future projects that capitalize on their complementary strengths. Leti has joined the network of selected partners initiated by ARaymondlife according to their know-how and capabilities to guide its product-development projects, and ARaymondlife is a preferred partner for the development platform of medical devices that Leti has recently established.

“This partnership combines our competencies in ways that will significantly speed the development and time-to-market of analytical tools and systems for Leti’s partners and ARaymondlife customers,” said Leti CEO Marie Semeria. “It also capitalizes on the technological diversity of the local ecosystem and underscores the Grenoble region’s excellence in medical technology.”

By combining their complementary strengths, the partners expect to support the development of turnkey solutions for companies that want to introduce new products in the medical technology industry, but require additional analytical resources, technical competencies or manufacturing tools.

“The strict standards and high costs for developing medical devices require that prototypes used for clinical testing not only meet quality regulations, but that also are almost identical to the final product,” said Philippe Daurenjou, ARaymondlife Commercial Director. “This partnership with Leti uses our complementary strengths to meet those requirements effectively and cost efficiently, and make our customers more competitive.”

The two partners anticipate working together on projects that will combine Leti’s expertise in developing analytical protocols with Araymondlife’s manufacturing capacity. On those projects, ARaymondlife would be involved very early in the development cycle to check the viability of the proposed solution in the manufacturing processes. The team will make modifications to improve the reliability of the product and reduce production costs, as needed.

In addition to its med-tech uses, Leti’s technology also is well-suited for rapid and cost-effective onsite analysis in environmental, agricultural and veterinary applications.

In a new study recently published in Nature Nanotechnology, researchers from Columbia Engineering, Cornell, and Stanford have demonstrated heat transfer can be made 100 times stronger than has been predicted, simply by bringing two objects extremely close–at nanoscale distances–without touching. Led by Columbia Engineering’s Michal Lipson and Stanford Engineering’s Shanhui Fan, the team used custom-made ultra-high precision micro-mechanical displacement controllers to achieve heat transfer using light at the largest magnitude reported to date between two parallel objects.

This is a still shot from a video of the high-precision micro-electromechanical system (MEMS) used to control the distance between two beams at different temperatures. The video is taken under a high magnification microscope. The whole video frame dimension is comparable to the diameter of a strand of human hair. Credit: Raphael St-Gelais, Lipson Nanophotonics Group, Columbia Engineering

This is a still shot from a video of the high-precision micro-electromechanical system (MEMS) used to control the distance between two beams at different temperatures. The video is taken under a high magnification microscope. The whole video frame dimension is comparable to the diameter of a strand of human hair. Credit: Raphael St-Gelais, Lipson Nanophotonics Group, Columbia Engineering

“At separations as small as 40 nanometers, we achieved almost a 100-fold enhancement of heat transfer compared to classical predictions,” says Lipson, Eugene Higgins Professor of Electrical Engineering and professor of applied physics. “This is very exciting as it means that light could now become a dominant heat transfer channel between objects that usually exchange heat mostly through conduction or convection. And, while other teams have demonstrated heat transfer using light at the nanoscale before, we are the first to reach performances that could be used for energy applications, such as directly converting heat to electricity using photovoltaic cells.”

All objects in our environment exchange heat with their surroundings using light. This includes the light coming at us from the sun, the glowing red color of the heating element inside our toaster ovens, or the “night vision” cameras that enable image recording even in complete darkness. But heat exchange using light is usually very weak compared to what can be achieved by conduction (i.e., by simply putting two objects in contact with each other) or by convection (i.e., using hot air). Radiative heat transfer at nanoscale distances, while theorized, has been especially challenging to achieve because of the difficulty of maintaining large thermal gradients over nanometer-scale distances while avoiding other heat transfer mechanisms like conduction.

Lipson’s team was able to bring objects at different temperatures very close to each other–at distances smaller than 100 nanometers, or 1/1000th of the diameter of a strand of human hair. They were able to demonstrate near-field radiative heat transfer between parallel SiC (silicon carbide) nanobeams in the deep sub-wavelength regime. They used a high-precision micro-electromechanical system (MEMS) to control the distance between the beams and exploited the mechanical stability of nanobeams under high tensile stress to minimize thermal buckling effects, thus keeping control of the nanometer-scale separation even at large thermal gradients.

Using this approach, the team was able to bring two parallel objects at different temperatures to distances as small as 42 nm without touching. In this case they observed that the heat transfer between the objects was close to 100 times stronger that what is predicted by conventional thermal radiation laws (i.e. “blackbody radiation”). They were able to repeat this experiment for temperature differences as high as 260oC (500oF) between the two objects. Such high temperature difference is especially important for energy conversion applications since, in these cases, the conversion efficiency is always proportional to the thermal difference between the hot and the cold objects involved.

“An important implication of our work is that thermal radiation can now be used as a dominant heat transfer mechanism between objects at different temperatures,” explains Raphael St-Gelais, the study’s lead author and postdoctoral fellow working with Lipson at Columbia Engineering. “This means that we can control heat flow with a lot of the same techniques we have for manipulating light. This is a big deal since there are a lot of interesting things we can do with light, such as converting it to electricity using photovoltaic cells.”

St-Gelais and Linxiao Zhu, who co-authored the study and is a PhD candidate in Fan’s group at Stanford, note that the team’s approach can be scaled up to a larger effective area by simply arraying several nanobeams–on top of a photovoltaic cell, for example–and by individually controlling their out-of-plane displacement using MEMS actuators. The researchers are now looking at applying their same approach for ultra-high-precision displacement control, this time with an actual photovoltaic cell to generate electricity directly from heat.

“This very strong, non-contact, heat transfer channel could be used for controlling the temperature of delicate nano devices that cannot be touched, or for very efficiently converting heat to electricity by radiating large amounts of heat from a hot object to a photovoltaic cell in its extreme proximity,” Lipson adds. “And if we can shine a large amount of heat in the form of light from a hot object to a photovoltaic cell, we could potentially create compact modules for direct conversion of heat to electrical power. These modules could be used inside cars, for instance, to convert wasted heat from the combustion engine back to useful electrical power. We could also use them in our homes to generate electricity from alternative energy sources such as biofuels and stored solar energy.”

By chemically modifying and pulverizing a promising group of compounds, scientists at the National Institute of Standards and Technology (NIST) have potentially brought safer, solid-state rechargeable batteries two steps closer to reality.

These compounds are stable solid materials that would not pose the risks of leaking or catching fire typical of traditional liquid battery ingredients and are made from commonly available substances.

Since discovering their properties in 2014, a team led by NIST scientists has sought to enhance the compounds’ performance further in two key ways: Increasing their current-carrying capacity and ensuring that they can operate in a sufficiently wide temperature range to be useful in real-world environments.

Considerable advances have now been made on both fronts, according to Terrence Udovic of the NIST Center for Neutron Research, whose team has published a pair of scientific papers that detail each improvement.

The first advance came when the team found that the original compounds — made primarily of hydrogen, boron and either lithium or sodium — were even better at carrying current with a slight change to their chemical makeup. Replacing one of the boron atoms with carbon improved their ability to conduct charged particles, or ions, which are what carry electricity inside a battery. As the team reported in February in their first paper, the switch made the compounds about 10 times better at conducting.

But perhaps more important was clearing the temperature hurdle. The compounds conducted ions well enough to operate in a battery — as long as it was in an environment typically hotter than boiling water. Unfortunately, there’s not much of a market for such high-temperature batteries, and by the time they cooled to room temperature, the materials’ favorable chemical structure often changed to a less conductive form, decreasing their performance substantially.

One solution turned out to be crushing the compound’s particles into a fine powder. The team had been exploring particles that are measured in micrometers, but as nanotechnology research has demonstrated time and again, the properties of a material can change dramatically at the nanoscale. The team found that pulverizing the compounds into nanometer-scale particles resulted in materials that could still perform well at room temperature and far below.

“This approach can remove worries about whether batteries incorporating these types of materials will perform as expected even on the coldest winter day,” says Udovic, whose collaborators on the most recent paper include scientists from Japan’s Tohoku University, the University of Maryland and Sandia National Laboratories. “We are currently exploring their use in next-generation batteries, and in the process we hope to convince people of their great potential.”

Overall demand for optoelectronics, sensors, actuators, and discrete semiconductors softened in 2015 as the fragile global economy weakened, but these market segments are expected to stabilize in 2016 and gradually return to more normal growth rates in the second half of this decade, according to IC Insights’ new 2016 O-S-D Report—A Market Analysis and Forecast for Optoelectronics, Sensors/Actuators, and Discretes.  The 360-page report shows combined O-S-D sales growing 5% in 2016 to a new record-high $70.2 billion, after increasing just 3% in 2015 to the current annual peak of $66.6 billion.  O-S-D revenues accounted for nearly 19% of the semiconductor industry’s $353.7 billion sales total in 2015 versus about 81% coming from ICs (Figure 1), according to IC Insights’ newly released report.

osd market share

 

Total O-S-D revenues continued to outgrow the larger integrated circuit market, which dropped 1% last year to $291.5 billion, primarily because of the weak global economy and a 3% decline in memory IC sales.    O-S-D’s share of 2015 semiconductor sales was the highest it has been since 1988.  IC Insights expects the O-S-D marketplace to account for 20.0% of total semiconductor sales in 2020.

On the strength of optoelectronics and sensor products—including CMOS image sensors, high-brightness light-emitting diodes (LEDs), and devices built with microelectromechanical systems (MEMS) technology—total O-S-D sales have outpaced the compound annual growth rate (CAGR) of ICs since the mid-1990s.  IC Insights’ new report shows this trend continuing in the next five years.  The 2016 O-S-D Report says modest improvements in the global economy, steady increases in electronic systems production, and new end-use applications—such as wearable systems and connections to the Internet of Things (IoT)—are expected to collectively lift the three O-S-D market segments by a CAGR of 6.5% between 2015 and 2020 compared to a projected 4.9% annual growth rate for IC sales in the second half of this decade.

During 2015, the O-S-D marketplace was a mixed bag of double-digit growth in most optoelectronics products and sales declines in discretes and a number of large sensor categories.  Optoelectronics sales grew 11% to a record-high $35.2 billion in 2015 while the discretes market suffered its worst decline since the 2009 semiconductor downturn year, falling nearly 8% to $21.2 billion, says the new O-S-D Report.  The sensors/actuators market increased about 4% in 2015 to a record-high $10.2 billion, with steep price erosion in accelerometers, gyroscope devices, and magnetic-field sensors dragging down overall growth in this semiconductor segment, according to the report.  In 2016, optoelectronics sales are expected to increase 9% to $38.2 billion, while sensors/actuators revenues are forecast to rise again by 4% to $10.6 billion, and the commodity-filled discretes market is projected to grow just 1% this year.  Between 2015 and 2020, all three O-S-D market segments are forecast to expand by more normal annual dollar-sales growth rates—with optoelectronics rising by a CAGR of 8.3%, sensors/actuators increasing at a rate of 5.6%, and discretes being up by a CAGR of 3.5% (Figure 2).

osd return to normal

 

Steady demand in existing end markets and growth from new end applications are pushing ASIC design activity to new levels. This increase in growth is based on very good growth in the Mixed Signal ASIC market and in the Basic SoC market. The Basic SoC market is being driven by the emergence of the Internet of Things (IoT) and the need for silicon solutions for this segment. Mixed Signal ASIC designs have been growing for the last few years as more systems seek to interface to analog ‘real world’ functions. According to a new Semico Research report ASIC Design Starts for 2016 by Key End Market Applications (SC106-16, March 2016), the total ASIC design start market is expected to grow 5.0% in 2016 on top of a 4.5% growth rate in 2015.

“Increases in ASIC design start activity are key to the improving health of the semiconductor market going forward,” said Rich Wawrzyniak, Principal Analyst for ASIC and SoC at Semico Research Corp. “The steady increase in unit volumes in many end markets also has a positive impact on design start activity and provides great support for the 3rd Party IP market as well. A growing proportion of new growth is coming from IoT-type applications as more traditional end applications are seeing some slowness.”

Key findings of the report include:

  • Advanced Performance Multicore SoCs will grow 4.6% in 2016
  • 1st time SoC design efforts increase over the forecast period
  • Basic SoC design starts have the highest CAGR at 11.7% from 2015 – 2020
  • Unit shipments for Industrial applications lead the industry in CAGR followed by Consumer, Communications, Automotive/Transportation and Computer

Semico Research’s new report, ASIC Design Starts for 2016 by Key End Market Applications (SC106-16, March 2016), offers a comprehensive analysis of the ASIC design start landscape today and into the future and provides excellent data for product planning, marketing and sales activities at fabless semiconductor companies, 3rd Party IP vendors and major OEMs and IDMs. It includes:

74 end-market applications analyzed and organized into categories by Computer, Consumer, Communications, Industrial and Automotive.

Nine ASIC product types (including Mixed Signal), three SoC types, FPGAs and PLDs are analyzed by design starts with unit shipments for each.

Two years of history (2014 -2015) and a 5-year forecast (2016 – 2020) are provided.

Since 2000, we have entered the age of sensing and interacting with the wide diffusion of MEMS and sensors that give us a better, safer perception of our environment. MEMS have grown in volume to be almost a 15 billion units market today. And analysts believe that this market will double to almost 30 billion by 2020, in less than 5 years, according to the Status of the MEMS Industry, Yole Développement, May 2015.

Claire Troadec, MEMS & Semiconductor Manufacturing Analyst from Yole Développement (Yole), the “More than Moore” market research and strategy consulting proposes you to learn more about the MEMS & sensors challenges and identify the related opportunities for the next decade. So what can we expect?

Since its early beginning, MEMS technology has been considered as a “transfer function” technology: taking existing products such as Hg tilt sensors, syringe, galvanometric mirror and transforming them in IMU , micro-needles, micro-mirrors. The interest of MEMS relies in the miniaturization and lower cost manufacturing brought by a semiconductor technology.

Today the MEMS & Sensors industry is transitioning towards 3 main hubs: the inertial hub (a closed package hub), the optical hub and the environmental hub (open package hubs)

Looking closely at the inertial hub, complete integration has been achieved at sensor level. The miniaturization race is still ongoing to lower the sensor cost and developments are focusing on advanced packaging technologies (e.g. TSV, WLP) and power consumption reduction. Major developments occur at software level to achieve sensor fusion and get precise data acquisition, precise tracking within the environment. Hence the inertial Bill of Materials within a smartphone today is around US$1.

This is nothing compared to the US$10 spent for the optical hub within the same smartphone: imaging is highly valued by the end customer. This is part of our “human” nature, where vision represent around 83% of our external world perception .

And what about the environmental hub? At Yole, we do believe that the environmental hub is an interesting way for the MEMS industry to gain value. Therefore, particles, gas detection are real market pull applications which would make sense to be integrated in a smartphone. Some more integration could also be achieved by combining pressure and microphone for example. Of course, this increased integration is not an easy task but represents real market opportunities. Today’s environmental sensors’ Bill of Materials in a smartphone is around US$0.70 and could represent US$1.50 tomorrow with this increased integration path.

The MEMS Market is observing a strong paradox today

Increasing volumes driven by the consumer wave (more and more smartphones sold and more and more sensors integrated in smartphone) leading to sensor die size reduction to answer the strong price pressure dictated by the consumer market. But this affect sensors margins, which shrink if the process is not re-tuned to gain on margin again. Overall resulting in a stable or declining market in terms of value!

Thus is the MEMS industry digging its own grave with this commoditization paradox? How to exit from this scenario?

mems virtuous cycle

Well, one might take a step back and look at what the CMOS Image sensor industry has achieved. Driven by the self-love or narcissism of human kind, the front cameras of our smartphones have increased in resolution for us to achieve better quality images of “selfies”: Hence the front camera resolution has been increased by a factor 4 in 4 years, thanks to increased number of pixels and thus sensor die size, leading inevitably to higher sensor prices!

What can we learn from this story and apply to the MEMS industry to gain value?
More complexity at system level: drive for better accuracy/precise tracking and features, meaning:
•  Sensor fusion
•  More integration: Pressure + microphone for example
•  Improved environment tracking: particles and gas sensing

MEMS markets challenges are thus evolving
Power consumption is becoming a major trend while mobiles, tablets, wearables have to survive for long periods on battery while interacting with the environment (voice calls, Wi-Fi, Bluetooth, GPS , sensors …).

Sensor fusion, software and added features are the current battleground of the hubs integration path.
Finally the user case is definitely mandatory! The idea is to start with applications, and work downwards to the chips needed to support them. This will be easier for a system maker than a pure sensor player who is further away on the supply chain and thus further away from his final end user needs!

In brief a new virtuous cycle is needed for the MEMS industry to gain value and stop being limited by shrinking prices and margins.

ILLUS_MEMSVirtuousCycle_YOLE_March2016_2

Yole’s analysts highlight the MEMS market evolution and technology trends within the report Status of the MEMS Industry, yearly updated (2015 edition available on i-micronews.com – 2016 version to be released soon). Moreover make sure you will meet our analysts and debate with them at

   •  MEMS Engineer Forum (May 11&12, 2016 – Tokyo, Japan), within the MEMS trends worldwide session. Yole’s presentation is entitled “MEMS & Sensors for Smart Cities” and takes place on May 11 at 11:00 AM. Speaker: Claire Troadec, Technology & Market Analyst, MEMS & Semiconductor Manufacturing, Yole Développement
•  2016 Sensors Expo & Conference (June 21 – 23, 2016 – McEnery Convention Center, San Jose, CA), Pre-Conference Symposium 3 entitled “IoT 2.0 – Sensor Innovation Moves From “Smart” to “Intelligent”” on June 21 from 9:00 AM to 5:00 PM. Speaker: Guillaume Girardin, Technology & Market Analysts, MEMS & Sensors, Yole Développement.

Luminaries from the micro-electromechanical systems (MEMS) industry are spurring entrepreneurship by hosting the first “MEMS Shark Pup Tank” at Hilton Head 2016 Workshop, an interactive science and technology conference on solid-state sensors, actuators and microsystems, June 5-9, 2016 in Hilton Head, SC.

“Bringing a new MEMS device to market can feel like a Herculean task as there are so many moving parts to the process,” said Jessica Gomez, founder and CEO of Rogue Valley Microdevices. “Given this reality, a highly accomplished group of MEMS industry experts aim to lower the barrier to entry for entrepreneurs who want to introduce MEMS-based products that could influence the global economy by 2025. MEMS Shark Pup Tank is the product of their combined vision, and we are thrilled to play a part by contributing foundry services to the event’s champion.”

The MEMS Shark Pup Tank Champion will receive:

  • Product development/strategy consulting and patent consulting time by industry experts:
  • $10,000 in MEMS foundry services from Rogue Valley Microdevices, a full-service precision MEMS foundry
  • 6 months license of MEMS Pro software from softMEMS, a leading developer of MEMS software design tools
  • One year membership in MEMS & Sensors Industry Group, the trade association advancing MEMS and sensors across global markets

The MEMS Shark Pup Tank runner-up will also receive an award package.

Submission Deadline: March 31, 2016

Teams must submit their business plan by March 31, 2016 by visiting: http://www.hiltonhead2016.org/events/shark.html

Researchers at MIT and other institutions have found a new phenomenon in the behavior of a kind of quasiparticles called plasmons as they move along tiny ribbons of two-dimensional materials such as graphene and TMDs (transition metal dichalcogenides), which have a hexagonal structure resembling chicken wire. The team found that these plasmons can be separated into two different streams moving in opposite directions at the edges of the ribbons, like traffic on a two-lane highway, without the need for strong magnetic fields or other exotic conditions.

The new research was carried out by MIT associate professor of mechanical engineering Nicholas X. Fang, recent PhD graduate from that department Anshuman Kumar, and four other researchers from the University of Wisconsin at Milwaukee, Hong Kong Polytechnic University, and the University of Minnesota. The work was reported in a paper in the journal Physical Review B.

Other groups had previously observed such separated flows, Fang says, but that previous work required the use of powerful magnetic fields. Instead, the new process relies largely on optical effects, he says, using beams of circularly polarized light.

The findings are based on exotic states of matter that can occur in two-dimensional materials that, unlike graphene, have a characteristic known as a bandgap, necessary for devices such as transistors or solar cells (and also in graphene that is modified to have a bandgap). These states of matter are based on quantum physics phenomena such as Berry curvature, which occur in configurations known as massive Dirac systems. Although such systems are a hot area of research these days, the researchers say this particular class of phenomena, involving surface electromagnetic properties known as surface plasmons, has been relatively unexplored until now.

Clustering in “valleys”

In the new work, the team showed that shining beams of circularly polarized light onto the graphene ribbons causes electrons in the material to cluster into two different “valleys” in the electronic band structure. The peculiar symmetry properties of this system gives rise to a phenomenon called Berry curvature, which can be thought of as an artificial magnetic field.

Under these conditions, these valleys correspond to motions of the plasmons — which are a kind of oscillation of electron density in the material — in opposite directions on the two edges of the material. The graphene ribbons are just 50 nanometers (billionths of a meter) in width.

This effective magnetic field can be measured by sending in a second polarized beam, whose transmission can then be detected so that the changes in its polarization give a direct measurement of the effects taking place in the surface plasmons.

“This is exciting,” Fang explains, because it opens up a whole new approach to both manipulating the electromagnetic behavior of such systems and measuring the results of these manipulations.

This could suggest possibilities for new kinds of electro-optical devices, he says. For example, some experimental photonic systems require devices called optical isolators, which prevent beams of light in precision optical systems from being reflected back to their source and causing interference. But these isolators, which require strong magnetic fields, are inherently bulky, he says, limiting the usefulness of such systems. “With this concept,” he says, “it’s possible to replace these bulky optical isolators with one monolayer of two-dimensional material.”

Chip-scale isolation

With such a system, Kumar says, it should be possible “to do chip-scale optical isolation without the need for a magnetic field.” To achieve the same degree of optical isolation that this system would provide with a beam of light, Kumar says, with a conventional system would require a magnetic field with a strength of 7 tesla — a very strong field that would require a special research facility. (By comparison, the Earth’s magnetic field measures just 32 millionths of a tesla).

Theoretically, this could lead to applications such as new types of memory devices where information could be both written and read by using beams of polarized light, making them relatively immune to electromagnetic or other kinds of interference, the researchers say.