Category Archives: Advanced Packaging

STMicroelectronics today announced the winners of the Singapore Area University iNEMO Design Contest 2013. The winning teams successfully conceptualized, developed and built demonstrable prototypes of entirely new applications using ST’s iNEMO MEMS sensor-fusion modules.

"We are impressed by the students’ ability to quickly grasp this technology to create working prototypes addressing new and diverse areas of application such as fitness, recreation, healthcare, navigation and industrial applications,” said Fabio Pasolini, general manager of the Motion MEMS division at STMicroelectronics. “These achievements perfectly reflect the vision STMicroelectronics has for MEMS technology, pushing its boundaries beyond the applications in smartphones, consumer electronics and automotive safety that we are more familiar with to create new applications and markets."

The objective of the iNEMO Design contest is to encourage students to think outside the box and create entirely new applications for MEMS sensors. MEMS technology essentially provides the "Smart" functionality in modern-day electronics, making it able to "sense" specific changes in its environment and react accordingly.

The contest participants, comprised of selected final-year engineering students from the National University of Singapore and the Nanyang Technological University, were paired in teams of two. Twelve teams competed, sponsored by ST with iNEMO modules, technical support and the financial support of SGD 1,000 per team for the purchase of 3rd-party materials. The submissions for the iNEMO contest were also part of the students’ final-year project.

The challenge to develop original life-enhancing applications with the latest sensor technology spurred the students to stretch their creativity while acquiring a clear understanding of market needs, said Professor Cheng Tee Hiang of Nanyang Technological University.

“This is the real industry environment they will have to function in and this program is a powerful teaching tool to that end,” he concluded.

ST sees MEMS technology bringing a lot of "Smart" features into many diverse areas including healthcare, wellness, recreation, navigation, security and industrial applications. The students participating in the iNEMO Design Contest were encouraged to create new applications in such areas and originality of ideas and real-life practicality were among the key winning criteria.

The champion team, comprised of Joel Ye Zhu’En and Benjamin Pong Xiang Ming from The National University of Singapore, developed a video camera stabilizer for aerial videography. The volatile swaying experienced in aerial videography makes it impossible for a video camera to fix its frame of focus on a specific target. Using the iNEMO to sense the multi-directional movements experienced by the camera, the module controls multiple motors attached to the camera platform to compensate for any swaying in any direction so that the camera maintains its frame of focus on a specific target. Joel and Benjamin’s idea has many possible industrial applications involving aerial and marine surveillance or videography where the camera platform suffers from volatile swaying or movement. The champion team wins a SGD 10,000 cash prize sponsored by ST.

The first runner-up team comprising Li Shiwei and Wu Haozhou from The Nanyang Technological University developed a "smart" dumbbell that is able to manage the entire training regimen of the user, as well as detect if the swing angle and velocity of the lift is incorrect and inform the user, improving their exercise skills. The first runner-up team wins a SGD 5,000 cash prize sponsored by ST.

The second runner-up team comprising Pushpaleela Prabakar and Nallasamy Suriya from The National University of Singapore used the iNEMO technology to transform an ordinary bicycle into a "smart" bicycle. The application measures the distance cycled and calculates the calories burnt, as well as it offers safety features such as automatically ringing a bell when turning a blind corner or indicating to the user the presence of nearby vehicles. The second runner-up team wins a SGD 3,000 cash prize sponsored by ST.

With Microsoft introducing Windows 8 operating system that provides the touch interface in the fourth quarter of 2012, notebook PCs with touch-screen panels were released. And this led to the opening of a new market, for projected capacitive touch panels of 10 inches or larger.

There have been issues with touch-screen notebooks in its initial market, and some may rush to call it a failure. But it’s been only less than a year since such laptops were released, and thus it is yet too early to make any decision. True. Looking at the business plans of major laptop makers for 2013, touch-screen notebooks should hold at least 10 percent of the total laptop shipments. In particular, brands from the great China region, including Lenovo, Acer and Asus, have set higher targets of achieving more than 20 percent. 

According to a research by Displaybank, acquired by IHS, total shipments of notebooks with touch screens were 4.57 million units in the first quarter of 2013, up 51.8 percent from a quarter earlier. The touch laptops made up almost 10 percent of the overall notebook market, whose shipments posted 46 million units. Considering that the market is at its initial stage, the penetration rate of touch-screen notebooks is quite high.

first quarter results of touch-screen notebook shipments
(Source: Displaybank, “Touch Panel Shipment Database – Notebook PC,” Q1-13)

With touch-screen notebooks released, manufacturing larger projected capacitive touch panels is accelerating and touch-screen panel related companies are trying hard to be the first to lead the market. Unfortunately, however, as there are no data on touch laptop market good enough to refer, it is not easy for the companies in the industry to set a business plan.

Displaybank published a quarterly “Touch Panel Shipment Database – Notebook PC” report to help them understanding the notebook-use projected capacitive touch panel industry quickly and accurately. The report provides quarterly shipments of touch-screen notebooks by unit/area/value; by inch; by brand; by form factor; by touch panel layer; by touch panel module and controller IC maker; and by cover window materials and bonding type, as well as top five models in terms of shipments.

Displaybank says the report should offer insight into the related market and industry to notebook set makers that are interested in notebook-use projected capacitive touch panels and companies related to touch panel modules, parts and raw materials.

last power logoLAST POWER, the European Union-sponsored program aimed at developing a cost-effective and reliable technology for power electronics, today announced its three-year program achievements.

Launched in April 2010 by the European Nanoelectronics Initiative Advisory Council (ENIAC) Joint Undertaking (JU), a public-private partnership in nanoelectronics, LAST POWER links private companies, universities and public research centers working in the field of wide bandgap semiconductors (SiC and GaN). The consortium members are STMicroelectronics (Italy), project coordinator, LPE/ETC (Italy), Institute for Microelectronics and Microsystems of the National Research Council -IMM-CNR (Italy), Foundation for Research & Technology-Hellas – FORTH (Greece), NOVASiC (France), Consorzio Catania Ricerche – CCR (Italy), Institute of High Pressure Physics – Unipress (Poland), Università della Calabria (Italy), SiCrystal (Germany), SEPS Technologies (Sweden), SenSiC (Sweden), Acreo (Sweden), Aristotle University of Thessaloniki – AUTH (Greece).

The main achievements in SiC-related efforts were based on the demonstration by SiCrystal of large-area 4H-SiC substrates, 150mm in diameter, with a cut-off angle of 2°-off axis. The material quality, both in crystal structure and surface roughness, is comparable with the standard 100mm 4°-off material available at the beginning of the project. At LPE/ETC, these substrates have been used for epitaxial growth of moderately doped epi-layers suitable for the fabrication of 600-1200V JBS (Junction Barrier Schottky) diodes and MOSFETs, owing to the development of a novel CVD reactor for the growth on large-area (150mm) 4H-SiC.

The quality of the epitaxial layer enabled the fabrication of JBS (Junction Barrier Schottky) diodes in the industrial production line at STMicroelectronics. The characterization of the first lots showed electrical performance comparable with the state-of-the-art 4°-off material. In this context, the fundamental technological step was the chemical mechanical polishing (CMP) process — StepSiC  reclamation and planarization — implemented at NOVASiC, which is a key issue both for the preparation of the substrates before epitaxial growth and for the sub-nanometric control of the surface roughness of the device active layers. Within the project, the same company also developed epitaxial growth capability for both MOSFET and JFET devices.

Additional research activities in SiO2/SiC interfaces have been carried out in collaboration with ST and IMM-CNR to improve the channel mobility in 4H-SiC MOSFETs.

Finally, novel technological modules for high-temperature 4H-SiC JFETs and MOSFETs have been developed in collaboration between Acreo and FORTH, with the support of CCR for the study of molding compounds and "lead-free" die-attach materials for reliable packaging solutions.

The LAST POWER project also researched the use of GaN-based devices in power-electronics applications. In particular, ST successfully obtained the development of AlGaN/GaN HEMTs epitaxial structures grown on 150mm Si substrates, reaching a target of 3mm thickness and 200V breakdown. LAST POWER worked with IMM-CNR, Unipress, and ST to develop the technological steps for normally-off AlGaN/GaN HEMTs with a "gold-free" approach. The process modules are fully compatible with the device-fabrication flow-chart set in the ST production line and are being integrated for HEMTs fabrication. The fruitful interaction between the project partners working on material growth and device technology has enabled important steps towards monolithic integration of GaN-based and SiC-based devices, as both technologies have been successfully proven on 2°-off axis 4H-SiC substrates.

Original equipment manufacturers (OEMs) are increasingly turning to electronics manufacturing service (EMS) providers to better handle the escalating volumes of electronic content in the medical industry. With opportunities for high-level product assembly and complete build projects expected to increase, the potential for EMS in the medical industry will progress gradually over the next few years

New analysis from Frost & Sullivan, “EMS Opportunities in the Medical Industry,” research finds that the market earned revenue of more than $16.43 billion in 2012 and estimates this to reach $34.38 billion in 2019.

 “The challenge in maintaining certified, state-of-the-art manufacturing facilities and complex supply chain operations is that it strains OEMs’ profit margins, compelling them to adopt EMS,” said Frost & Sullivan Electronics and Manufacturing Equipment Research Analyst Lavanya Rammohan. “EMS providers, with their exposure to various verticals, are the ideal solution to manage the electronics boom in healthcare brought about by the use of wireless communications, robotics and software.”

Rising demand for engineering support as well as improving EMS competencies in product introduction, manufacture design and value-add services will boost EMS growth in the medical industry.

However, despite EMS providers’ growing expertise, the risk of liabilities prevents OEMs from outsourcing several services. Stringent regulations place medical OEMs under huge scrutiny, thereby limiting their outsourcing to tactical operations, such as printed circuit board assembly and sub-system assembly.

Strict regulations also lengthen the outsourcing cycle, as OEMs are cautious in decision-making and favor EMS vendors with proven expertise. Manufacturers’ preference to retain intellectual property and strategic customer touch points reduces revenue possibilities for EMS dealers.

“EMS suppliers need to focus on developing strong relationships with original equipment manufacturers to build trust and capability, as OEM-EMS partnerships require long-term commitment in order for outsourcing to increase,” concluded Rammohan. “Service providers must be aware of industry trends, including financial models, long sales realization cycles, manufacturing challenges, supply chain complexities, certifications and audits, to offer all-round services.”

MEMS Industry Group (MIG), the industry organization advancing MEMS across global markets, today announced its conference and exposition line-up for the 2013 Sensors Expo and Conference, an event in North America for designing sensors and sensor-integrated systems. Joined by member-companies, MIG will examine MEMS sensor fusion through a pre-conference symposium. MIG speakers will also address MEMS in consumer, industrial and medical/healthcare markets through a MEMS conference track and MEMS Pavilion exhibition area on the show floor.

Pre-conference Symposium: MEMS Sensor Fusion

During the MEMS Pre-conference Symposium—“MEMS Sensor Fusion: Faster: Stronger. Smarter.” on June 4, MIG speakers will discuss how sensor fusion—the intelligent combination of data from several sensors for the purpose of improving application or system performance—is moving rapidly into the commercialization phase.

“MEMS sensor fusion offers the leading approach to meeting or exceeding power, performance and cost requirements in heterogeneous embedded systems—including mobile handsets and tablets,” said Karen Lightman, executive director, MEMS Industry Group. “And with MEMS sensors critical to the Internet of Things, embedded systems designers are increasingly hungry for information on sensor fusion tools and techniques. That is why, in our third consecutive year of playing a significant role at Sensors Expo, we decided to focus our symposium on this exciting topic.”

The MEMS Pre-conference Symposium will feature:

  • Introduction—Karen Lightman, executive director, MEMS Industry Group
  • MEMS Analyst Panel: Sensor Fusion Growth and Trends—Marwan Boustany, senior analyst MEMS + SENSORS, IHS iSuppli; Laurent Robin, market and technology analyst, Yole Développement; Tony Massimini, chief of technology, Semico Research
  • Simplifying Sensor Fusion—Marcellino Gemelli, senior marketing manager, Bosch Sensortec
  • How to Use Always-On Sensors for Context Awareness: Getting More Out of Mobile Devices—Kevin Shaw, CTO, Sensor Platforms
  • Architectures for “Always-On” Motion Sensor Fusion for Mobile Devices—Per Slycke, CTO and  founder, Xsens Technologies BV
  • Piezoelectric MEMS MicroPowerGenerators for Smart Wireless Sensor Networks—Kathleen Vaeth, vice president of engineering, MicroGen Systems
  • How the Micro-Amp Magnetic Gyro Opens up New Possibilities for Mobile Applications—John Chong, director, product engineering, Kionix
  • Android as a Platform for Sensor Fusion Education and Evaluation—Mike Stanley, systems engineer, Freescale Semiconductor
  • Sensor Modeling for MEMS Sensor Fusion—MaryAnn Maher, CEO and founder, SoftMEMS
  • MEMS Sensor Fusion Panel: A Dive into Standardization—David DiPaola, principal, DiPaola Consulting; Ken Foust, sensor technologist, Intel Corp.; Becky Oh, president and CEO, PNI Sensor Corporation; Satwant Singh, MIPI Alliance
  • Thinking Outside the (Mobile) Box: Other Important High-Value Applications for Sensor Fusion—Alissa Fitzgerald, founder and managing member, A.M. Fitzgerald & Associates

For more information on the MEMS conference track and more at the 2013 Sensor Expo and Conference, visit http://bit.ly/MIGse13.

MEMS Industry Group (MIG) is the trade association advancing MEMS across global markets. More than 140 companies and industry partners comprise MIG, including Analog Devices, Applied Materials, Bosch, Freescale Semiconductor, GE, Honeywell, HP, Intel, InvenSense, Murata Electronics Oy, OMRON Electronic Components, Qualcomm Technologies, Inc., STMicroelectronics and Texas Instruments.

David DiPaola is managing director for DiPaola Consulting, a company focused on engineering and management solutions for electromechanical systems, sensors and MEMS products.  A 17-year veteran of the field, he has brought many products from concept to production in high volume with outstanding quality.  His work in design and process development spans multiple industries including automotive, medical, industrial and consumer electronics.  He employs a problem solving-based approach working side-by-side with customers from startups to multi-billion dollar companies.  David also serves as senior technical staff to The Richard Desich SMART Commercialization Center for Microsystems, is an authorized external researcher at The Center for Nanoscale Science and Technology at NIST and is a senior member of IEEE. Previously,he has held engineering management and technical staff positions at Texas Instruments and Sensata Technologies, authored numerous technical papers, is a respected lecturer and holds five patents. Visit www.dceams.com.

After a functional A-sample prototype is built, it doesn’t take long for a project to gain traction that has market pull.  This is usually the point that a project becomes highly visible within a company and it enters the Technology Development Process (TDP). The TDP is made up of multiple phases including concept, prototype, pilot and production with gates at the end of each phase.  Design and process reviews are required at each gate but may also occur within a phase. These reviews are an open forum for communication of project progress and gaps towards technological, business and schedule milestones. Furthermore, the product is constantly evaluated against the market need and potential changes in market that may have occurred. The audience for the reviews at a gate include peers and management, who provide feedback on the project to date and collectively decide whether additional work is needed to complete the current phase or the completed work is sufficient to allow the project to proceed to the next phase with additional funding.  In certain instances, a project that has not met all of the deliverables may be allowed to proceed to the next phase, but under strict conditions, that must be fulfilled within a given timeline.  The goal of the TDP is to focus the team on high quality execution, effectively screen projects allowing only the best to proceed and hence accelerate successful innovation and profitability. 

The MEMS Industry Group (MIG) Technology Development Process Template is an excellent tool for companies to use to implement the TDP within their organization (Marty et al. 2013). The goal of the TDP was to create a simplified frame work that could be easily customized to fit a company’s needs. The TDP structure shown below is a slightly modified version of the TDP developed by MIG.  In this version there are four major phases including concept, prototype, pilot and production with three major gates. 

 

Figure 1

TDP Structure

MEMS new product development

 

 The concept phase is where ideas are generated and the initial A-samples are developed. It is also where the business case is first generated and the market need is defined.  It is highly desirable to have market pull at this point. The prototype phase is where the design is developed in detail and B-samples are fabricated to support various levels of validation. The outcome of the prototype phase is to have design that can be manufactured in volume production. Towards the end of the prototype phase, production tooling is often released. The pilot phase is where production tooling is built and qualified.  In addition, the product is made on production tooling (C-samples) and revalidated. It is important to note that there should be no change in the product design between the last revision in prototype and the first samples off the production tooling. The production phase is low to high volume production ramp. Often customers will require revalidation of products in production once a year for the life of the product.   

At each gate, there is a design and process review for the project. In order for the team to be focused and efficient, there needs to be a clear set of deliverables defined for completion of each phase.  These deliverables range from business and market definition to project technical details to production launch.  This checklist provides an in-depth set of deliverables for the design reviews at each gate that can be tailored to the specific needs of an organization. It is noted that a fourth gate is common 3-6 months after production launch to review project status but is not depicted in Figure 1.

This table can be downloaded from the following link in PDF format.  Many of the items listed above are self-explanatory.  Others are explained in more detail in previous blogs posts such as DFMEA and tolerance stacks.  

The Technology Development Process is an essential element of successful MEMS new product launches.  The Design Review Checklist can also provide a frame work for discussion between management and engineers on required deliverables to pass a particle gate.  With improved communication and efficient execution of technology development, the TDP is a great tool for accelerating innovation and profitable MEMS products.  In next month’s blog, the necessary attributes of a MEMS engineer for new product development will be discussed.  

Works Cited:

Marty, Valerie, Dirk Ortloff, and David DiPaola. "The MIG Technology Development Process       Template." MEMS Industry Group, Mar. 2013. Web. 28 Apr. 2013.

 

Combo MEMS sensors for automotive applications are off to another exhilarating ride this year as revenue continues to climb, spurred by rapidly accelerating use in car safety systems, according to an IHS iSuppli MEMS and Sensors Report from information and analytics provider IHS.

Global revenue in 2013 for combo inertial sensors used in motor vehicles will reach a projected $163 million, up a notable 77 percent from $92 million last year. The anticipated increase continues a hot streak for the market, which saw a phenomenal 338 percent surge last year from just $10 million in 2011, as shown below.

MEMS combo sensors

Combo inertial sensors are multiple-sensor devices integrating accelerometers, gyroscopes into a single package, providing inertial inputs to the electronic stability control (ESC) system in cars to prevent or minimize skidding.

“ESC systems are mandated in North America, Europe and in other areas where the edicts are maturing, such as Australia, Japan, Canada and South Korea,” said Richard Dixon, Ph.D., principal analyst for MEMS and Sensors at IHS. “But a huge growth opportunity exists in untapped territories like China, which would significantly impact the penetration of ESC worldwide given the vast size of the Chinese market. Such gains, in turn, would provide tremendous impetus and momentum for automotive combo sensors overall.”

Why combos?

Three architectures are currently possible for ESC systems in cars: on a printed circuit board as a separate ESC engine control unit (ECU); attached to the brake modulator to save cabling; or collocated in the airbag ECU. Of these three usable locations, the current trend favors placing ESC systems in the airbag ECU to achieve a smaller footprint and greater efficiency, given that there is a space constraint for the ECU in this position near the cup holder in a vehicle, which favors an architecture of reduction.

All told, as much as a fivefold reduction in space could be achieved for the sensors in a combo-sensor ESC system made by a manufacturer like Continental, compared to the same accomplished via separate sensors.

A non-combo solution also exists in the form of the sensors separately mounted on the printed circuit board. But deploying the sensors in a combo form factor saves not only on packaging cost but also on expensive real estate for the semiconductors being used, since the two sensors in the combo package share the same application-specific integrated circuit.

Cost is a factor

A paramount issue for ESC systems is cost. Cost is especially important because ESC formerly was considered an optional feature—but since being mandated by governments—it now has attained the same required status as the seat belt.

As a result, the entire supply chain and price structure for automotive combo sensors has been experiencing huge pressure, exerted from car makers down the chain. Tier 1 companies then pass on this pressure to their suppliers, accounting for the accelerated move to provide efficient combo sensor solutions for inertial sensors in the system.

Because of such pressure, some top-tier companies have indicated that only legacy businesses will use older arrangements featuring separate sensors—not a combo solution—on a printed circuit board in the future. All new car models will use combo sensors.

Top suppliers identified

The major suppliers of automotive combo inertial sensors are Bosch of Germany and Japan’s Murata (formerly VTI). Two other potential manufacturers, Panasonic of Japan and Massachusetts-based Analog Devices, will need to develop similar solutions to have a chance in the market.

For its part, Panasonic has indicated that a product will be available by 2014. Panasonic Industrial makes the gyroscope part of the solution, while Panasonic Electric Works makes the accelerometer component.

However, the two entities do not have a good track record of working together, so it remains to be seen how soon a unified combo sensor solution from Panasonic will come to market.

Meanwhile, Analog Devices is divulging little information, but it will almost certainly develop a combo sensor solution, IHS iSuppli believes, based on an analysis of developments surrounding the competition.

TowerJazz, the global specialty foundry leader, today announced collaboration with TLi (Technology Leaders and Innovators), a fabless company that designs non-memory integrated circuits (ICs) focused on timing controllers and driver ICs on TFT-LCD panel modules. TLI says they have developed an acceleration sensor control IC and proximity illumination sensor IC based on TowerJazz’s 0.18um CMOS technology, which enables TLi to provide local offerings to mobile phone suppliers in Korea where the market leaders are located.

As of 2012, the worldwide mobile phone market was 1.7 billion dollar and 43 percent of this was attributed to smartphones with acceleration sensor control ICs and proximity and illumination sensor ICs. The portion of smartphones with these ICs is expected to grow steadily, and TLi is targeting this fast growing market with two of its products utilizing TowerJazz’s process. A mass production is expected to start in Q3, 2013.

The acceleration sensor market is mostly dominated by a few major foreign companies, however in January of this year, TLi succeeded in developing an acceleration sensor control IC and a proximity illumination sensor IC in Korea. These products are the first released from the very close collaboration between TowerJazz and TLi. By utilizing the advanced features of TowerJazz’s 0.18um CMOS process, TLi realized accurate modeling as well as flash memory without mask adder for its acceleration sensor control IC and succeeded in realizing the sensing block without expensive color filtering for its proximity illumination sensor IC.

"We have been very pleased with our collaboration on these exciting products which has enabled us to provide local offerings to Korean mobile phone suppliers that are expected to be the most cost effective solutions in this market. This is the result of our close discussions with TowerJazz to utilize the advanced features of their 0.18 CMOS process. Also, these products showed full functionality from first silicon," said Soonwon Hong, vice president of TLi.

"Korea is an important region for technical and manufacturing innovation and we are very excited to work with a leading-edge partner such as TLi to enable localization of their specialized sensor ICs," said Michael Song, VP of Sales and president of TowerJazz Korea. "TLi has trusted us to co-develop and bring to market their latest products and we are pleased with the progress we have made in this region which is home to many leading semiconductor companies."

Researchers from IMDEA-Nanociencia Institute and from Autonoma and Complutense Universities of Madrid (Spain) have managed to give graphene magnetic properties. The breakthrough, published in the journal ‘Nature Physics’, opens the door to the development of graphene-based spintronic devices, that is, devices based on the spin or rotation of the electron, and could transform the electronics industry.

Scientists were already aware that graphene, an incredible material formed of a mesh of hexagonal carbon atoms, has extraordinary conductivity, mechanical and optical properties. Now it is possible to give it yet one more property: magnetism, implying a breakthrough in electronics.

magnetizing graphene
This is a computerised simulation of TCNQ molecules on graphene layer, where they acquire a magnetic order.

This is revealed in the study that the Madrid Institute for Advanced Studies in Nanoscience (IMDEA-Nanociencia) and Autonoma Autonomous (UAM) and Complutense (UCM) universities of Madrid have just published in the ‘Nature Physics’ journal. Researchers have managed to create a hybrid surface from this material that behaves as a magnet.      

"In spite of the huge efforts to date of scientists all over the world, it has not been possible to add the magnetic properties required to develop graphene-based spintronics. However these results pave the way to this possibility," said Prof. Rodolfo Miranda, director of IMDEA-Nanociencia.

Spintronics is based on the charge of the electron, as in traditional electronics, but also on its spin, which determines its magnetic moment. A material is magnetic when most of its electrons have the same spin.

As the spin can have two values, its use adds two more states to traditional electronics. Thus, both data processing speed and quantity of data to be stored on electronic devices can be increased, with applications in fields such as telecommunications, computing, energy and biomedicine.

In order to develop a graphene-based spintronic device, the challenge was to ‘magnetize’ the material, and researchers from Madrid have found the way through the quantum and nanoscience world.

The technique involves growing an ultra-perfect graphene film over a ruthenium single crystal inside an ultra high vacuum chamber whereorganic molecules of tetracyano-p-quinodimethane (TCNQ) are evaporated on the grapheme surface. TCNQ is a molecule that acts as a semiconductor at very low temperatures in certain compounds.

On observing results through a scanning tunneling microscope (STM), scientists were surprised: organic molecules had organised themselves and were regularly distributed all over the surface, interacting electronically with the graphene-ruthenium substrate.                                                    

"We have proved in experiments how the structure of the TCNQ molecules over graphene acquires long-range magnetic order with electrons positioned in different bands according to their spin," clarifies Prof. Amadeo L. Vázquez de Parga.

Meanwhile, his colleague Prof. Fernando Martin has conducted modelling studies that have shown that, although graphene does not interact directly with the TCNQ, it does permit a highly efficient charge transfer between the substrate and the TCNQ molecules and allows the molecules to develop long range magnetic order.

The result is a new graphene-based magnetized layer, which paves the way towards the creation of devices based on what was already considered as the material of the future, but which now may also have magnetic properties.

Quantum dots are tiny nanocrystals with extraordinary optical and electrical properties with possible uses in dye production, bioimaging, and solar energy production. Researchers at the University of Illinois at Chicago have developed a way to introduce precisely four copper ions into each and every quantum dot.

The introduction of these "guest" ions, called doping, opens up possibilities for fine-tuning the optical properties of the quantum dots and producing spectacular colors.

"When the crystallinity is perfect, the quantum dots do something that no one expected–they become very emissive and end up being the world’s best dye," says Preston Snee, assistant professor of chemistry at UIC and principal investigator on the study.

The results are reported in the journal ACS Nano, available online in advance of print publication. Incorporating guest ions into the crystal lattice can be very challenging, says UIC graduate student Ali Jawaid, first author of the paper.

Controlling the number of ions in each quantum dot is tricky. Merely targeting an average number of guest ions will not produce quantum dots with optimal electrical and optical properties.

Jawaid developed a procedure that reliably produces perfect quantum dots, each doped with exactly four copper ions. Snee believes the method will enable them to substitute other guest ions with the same consistent results.

"This opens up the opportunity to study a wide array of doped quantum dot systems," he said.

Donald Wink and Leah Page of UIC and Soma Chattopadhyay of Argonne National Laboratory also contributed to the study.

Support for the research came from UIC and the UIC Chancellor’s Discovery Fund and the American Chemical Society Petroleum Research Fund. The Materials Research Collaborative Access Team, a consortium for building and operating x-ray beamlines at Argonne’s Advanced Photon Source, is supported by the U.S. Department of Energy and the MRCAT member institutions. The use of the Advanced Photon Source was supported by the DOE Office of Basic Energy Sciences under contract DE-QC02-06CH11357.

UIC ranks among the nation’s leading research universities and is Chicago’s largest university with 27,500 students, 12,000 faculty and staff, 15 colleges and the state’s major public medical center. A hallmark of the campus is the Great Cities Commitment, through which UIC faculty, students and staff engage with community, corporate, foundation and government partners in hundreds of programs to improve the quality of life in metropolitan areas around the world.