Category Archives: LEDs

Researchers at Aalto University and VTT Technical Research Centre of Finland have succeeded in developing a method which helps to improve the relative uncertainty in measuring the luminous efficacy of LEDs from the approximate five percent of today to one per cent in the future. The results were just published in the Light: Science & Applications journal.

Thus far, solutions based on incandescent lamps have been used in photometry, i.e. in measuring light detected by the human eye, explains Tomi Pulli, a doctoral student at Aalto University.

“The photometers that lamp manufacturers use for calibrating their devices have been produced and calibrated for incandescent lamps, which results in errors when measuring the efficacy of LEDs. In our research, we used a LED lamp with a well-defined spectrum and a PQED detector, which we developed together with VTT MIKES Metrology and European partners, and whose spectral responsivity can be determined highly accurately. Therefore, there was no need for the problematic optical filters used in applications based on incandescent lamps. Indeed, accurately determining and analyzing the spectrum of the LED was the most challenging and crucial part of the research,” he revealed.

The detector used in measurements by Pulli and his co-researchers measures the illuminance of LEDs in a very small area. According to Professor Erkki Ikonen, the head of research, the next step will be to move onto measurements corresponding to real-life conditions for lighting.

“LED lamps emit light to all directions. In order to measure the luminous efficacy, we thus use a device called an integrated sphere, which takes into account light coming from different directions,” he specifies, and reminds that the history of LEDs is still short when compared to incandescent and fluorescent lamps. Therefore, there is still little information available on their actual efficacy and aging properties. Indeed, it is essential to determine luminous efficacy as accurately as possible so that such lamps can be introduced in the market that transform as much electrical energy into light useful to the human eye as possible.

So far, the portion of LEDs has been around 10 percent globally, but the amount is increasing at a rapid pace, Ikonen explains. Lighting amounts to approximately 20 percent of the electricity consumption in the world. Once the share of LEDs increases close to 50 percent, an improvement of as little as one percent in the accuracy of measuring the luminous efficacy of the lamps introduced in the market will mean saving billions of euros each year.

Individual transistors made from carbon nanotubes are faster and more energy efficient than those made from other materials. Going from a single transistor to an integrated circuit full of transistors, however, is a giant leap.

“A single microprocessor has a billion transistors in it,” said Northwestern Engineering’s Mark Hersam. “All billion of them work. And not only do they work, but they work reliably for years or even decades.”

When trying to make the leap from an individual, nanotube-based transistor to wafer-scale integrated circuits, many research teams, including Hersam’s, have met challenges. For one, the process is incredibly expensive, often requiring billion-dollar cleanrooms to keep the delicate nano-sized components safe from the potentially damaging effects of air, water, and dust. Researchers have also struggled to create a carbon nanotube-based integrated circuit in which the transistors are spatially uniform across the material, which is needed for the overall system to work.

Now Hersam and his team at Northwestern University have found a key to solving all these issues. The secret lies in newly developed encapsulation layers that protect carbon nanotubes from environmental degradation.

Supported by the Office of Naval Research and the National Science Foundation, the research appears online in Nature Nanotechology on September 7. Tobin J. Marks, the Vladimir N. Ipatieff Research Professor of Chemistry in Northwestern’s Weinberg College of Arts and Sciences and professor of materials science and engineering in the McCormick School of Engineering, coauthored the paper. Michael Geier, a graduate student in Hersam’s lab, was first author.

“One of the realities of a nanomaterial, such as a carbon nanotube, is that essentially all of its atoms on the surface,” said Hersam, the Walter P. Murphy Professor of Materials Science and Engineering. “So anything that touches the surface of these materials can influence their properties. If we made a series of transistors and left them out in the air, water and oxygen would stick to the surface of the nanotubes, degrading them over time. We thought that adding a protective encapsulation layer could arrest this degradation process to achieve substantially longer lifetimes.”

Hersam compares his solution to one currently used for organic light-emitting diodes (LEDs), which experienced similar problems after they were first realized. Many people assumed that organic LEDs would have no future because they degraded in air. After researchers developed an encapsulation layer for the material, organic LEDs are now used in many commercial applications, including displays for smartphones, car radios, televisions, and digital cameras. Made from polymers and inorganic oxides, Hersam’s encapsulation layer is based on the same idea but tailored for carbon nanotubes.

To demonstrate proof of concept, Hersam developed nanotube-based static random-access memory (SRAM) circuits. SRAM is a key component of all microprocessors, often making up as much as 85 percent of the transistors in the central-processing unit in a common computer. To create the encapsulated carbon nanotubes, the team first deposited the carbon nanotubes from a solution previously developed in Hersam’s lab. Then they coated the tubes with their encapsulation layers.

Using the encapsulated carbon nanotubes, Hersam’s team successfully designed and fabricated arrays of working SRAM circuits. Not only did the encapsulation layers protect the sensitive device from the environment, but they improved spatial uniformity among individual transistors across the wafer. While Hersam’s integrated circuits demonstrated a long lifetime, transistors that were deposited from the same solution but not coated degraded within hours.

“After we’ve made the devices, we can leave them out in air with no further precautions,” Hersam said. “We don’t need to put them in a vacuum chamber or controlled environment. Other researchers have made similar devices but immediately had to put them in a vacuum chamber or inert environment to keep them stable. That’s obviously not going to work in a real-world situation.”

Hersam imagines that his solution-processed, air-stable SRAM could be used in emerging technologies. Flexible carbon nanotube-based transistors could replace rigid silicon to enable wearable electronics. The cheaper manufacturing method also opens doors for smart cards — credit cards embedded with personal information to reduce the likelihood of fraud.

“Smart cards are only realistic if they can be realized using extremely low-cost manufacturing,” he said. “Because our solution-processed carbon nanotubes are compatible with scalable and inexpensive printing methods, our results could enable smart cards and related printed electronics applications.”

Semiconductor equipment manufacturer ClassOne Technology has today announced the appointment of Kevin Witt to the position of Chief Technology Officer. Part of the company’s initial executive team, Witt has served as ClassOne’s Vice President of Technology since 2013.

“I’m delighted to announce Kevin’s promotion,” said Byron Exarcos, President of ClassOne Technology. “He has more than 25 years in the industry, and the depth and breadth of his experience have contributed significantly to the rapid success we’ve enjoyed to date. His strengths will be even more important as he spearheads the development of our coming generations of cost-efficient, high-performance systems.”

Prior to joining ClassOne Technology Witt had been Director of Disruptive Technology at Semitool and was on the executive team that sold the company to Applied Materials. Witt has also held global marketing positions at Rodel and Solution Technology as well as engineering positions at AMD and Perkin Elmer. Subsequent to this, he cofounded and served as CTO/COO of Zinc Air, an energy storage company. He holds an MS degree in Materials Science and Engineering and a BS in Physics, both from the Rochester Institute of Technology.

Witt has been a key contributor in the development of ClassOne’s popular Solstice family of electroplating systems, which includes models for development and volume production. The Solstice S4 was recently given the BEST OF WEST Award at the SEMICON West 2015 Conference in San Francisco. ClassOne also provides the innovative Trident families of Spin Rinse Dryers (SRDs) and Spray Solvent Tools (SSTs). All are designed to deliver high-performance wet processing at an affordable price, aimed primarily at MEMS, Sensors, LEDs, RF, Interposers and other ≤200mm emerging markets. Described as providing “Advanced Wet Processing for the Rest of Us,” ClassOne systems are generally priced at less than half of what similarly configured tools from the larger manufacturers would cost.

Marking an industry first for emerging electronics devices, Semiconductor Research Corporation (SRC) today announced a significant expansion of its benchmarking research — a unique program that evaluates the relative capabilities of new and emerging computing devices.

SRC, the world’s leading university-research consortium for semiconductor technologies, is managing the initiative through its Nanoelectronics Research Initiative (SRC-NRI) and STARnet Research programs. The research will be led by the Georgia Institute of Technology’s Azad Naeemi, associate professor, Georgia Tech School of Electrical and Computer Engineering.

“Benchmarking guides university research funded through SRC — enabling concise communication of research outcomes, focusing researchers’ attention on key technical challenges and sparking invention,” said Tom Theis, executive director of SRC-NRI. “Professor Naeemi’s research is expected to take benchmarking of emerging devices to a new level of sophistication.”

Evaluating the performance of devices in representative “benchmark” circuits is a well-established engineering practice in the semiconductor industry. However, this new program is the first to develop a comparable methodology for evaluating the relative capabilities of emerging devices.

These emerging devices include, for example, transistor-like “steep slope” devices that can operate at very low voltage and, therefore, very low power, and non-volatile magnetic devices that combine the functions of logic and memory. The new devices operate by a variety of principles fundamentally different from those governing the operation of established silicon field-effect transistor technology.

In recent years, benchmarking of these devices has steadily increased in rigor. The Georgia Tech team — selected by a group of SRC member companies supporting the initiative including IBM, Intel Corporation, Micron Technology and Texas Instruments — will build on this foundation.

“This research will also enable selection of the most promising emerging devices for technology transfer to SRC member companies and for continued development in future SRC research programs,” said Gilroy Vandentop, executive director of STARnet Research.

Besides maintaining and improving the established benchmarking methodology, the Georgia Tech team is tasked with developing and evaluating benchmark circuits to better understand the potential of new devices for memory arrays, to explore and quantify the value of non-volatility and to measure the impact of various ways of implementing device-to-device connections. Perhaps most challenging, Prof. Naeemi will lead the development of a rigorous benchmarking methodology for non-Boolean (analog) computational circuits being explored for future applications such as artificial neural networks.

“Our team is chartered with maintaining and improving the established benchmarking methodology for emerging devices, evaluating the potential performance of the various SRC-NRI and STARnet devices in the established benchmark circuits,” said Naeemi. “We will incorporate additional device concepts as they emerge through ongoing research, and we will develop additional benchmark circuits to better understand the capabilities of these devices.”

The SRC benchmark program is a two-and-a-half year effort that funds research from July 1, 2015 through the close of 2017.

With the help of a semiconductor quantum dot, physicists at the University of Basel have developed a new type of light source that emits single photons. For the first time, the researchers have managed to create a stream of identical photons. They have reported their findings in the scientific journal Nature Communications together with colleagues from the University of Bochum.

A single-photon source never emits two or more photons at the same time. Single photons are important in the field of quantum information technology where, for example, they are used in quantum computers. Alongside the brightness and robustness of the light source, the indistinguishability of the photons is especially crucial. In particular, this means that all photons must be the same color. Creating such a source of identical single photons has proven very difficult in the past.

However, quantum dots made of semiconductor materials are offering new hope. A quantum dot is a collection of a few hundred thousand atoms that can form itself into a semiconductor under certain conditions. Single electrons can be captured in these quantum dots and locked into a very small area. An individual photon is emitted when an engineered quantum state collapses.

Noise in the semiconductor

A team of scientists led by Dr. Andreas Kuhlmann and Prof. Richard J. Warburton from the University of Basel have already shown in past publications that the indistinguishability of the photons is reduced by the fluctuating nuclear spin of the quantum dot atoms. For the first time ever, the scientists have managed to control the nuclear spin to such an extent that even photons sent out at very large intervals are the same color.

Quantum cryptography and quantum communication are two potential areas of application for single-photon sources. These technologies could make it possible to perform calculations that are far beyond the capabilities of today’s computers.

Imagine illuminating your home or business with flat, inexpensive panels that are environmentally friendly, easy on your eyes, and energy-efficient because they create minimal heat.

Now imagine how those panels could be used if they were as flexible as paper or cloth; the technology could be bent into shapes, fit the interior or exterior curves of vehicles, even be incorporated into clothing.

In “Flexible organic light-emitting diodes (OLEDs) for solid-state lighting” a team of researchers at Pohang (Republic of Korea) University of Science and Technology reports on advances in three key areas — flexible electrodes, flexible encapsulation methods, and flexible substrates — that make commercial use of such technology more feasible and closer to implementation. The article appears in the current issue of the Journal of Photonics for Energy, published by SPIE, the international society for optics and photonics.

Figure 9 from a new article in the Journal of Photonics for Energy is a schematic illustration of OLED structures with encapsulation: (a) conventional glass lid and (b) thin-film encapsulation. Credit: Min-Ho Park et al., Pohang University

Figure 9 from a new article in the Journal of Photonics for Energy is a schematic illustration of OLED structures with encapsulation: (a) conventional glass lid and (b) thin-film encapsulation. Credit: Min-Ho Park et al., Pohang University

OLEDs show promise as a future light source because of their thinness, light weight, energy efficiency, and use of environmentally benign materials. Companies such as Philips and LG Chemical have begun producing flat OLED panels that produce non-glare, UV-free light but very little heat, with no need for lamp shades or diffusers.

“The future trend in OLEDs is to make them on plastic substrates for flexibility, durability, and light weight. In this work, the authors review the technical challenges and solutions in this important subject,” said Franky So, Walter and Ida Freeman Distinguished Professor in Materials Science and Engineering at North Carolina State University, and an associate editor of the journal.

Min-Ho Park and other researchers at Pohang tested a variety of transparent electrodes as flexible alternatives to currently available devices based on indium tin oxide (ITO), which is brittle and increasingly expensive, and identified next steps toward making flexible solid-state lighting commercially feasible:

  • development of a flexible electrode that has high electrical conductivity, high bending stability, few defects, smooth surface texture, and high work function
  • reduction in the water-vapor transmission rate of materials used, to counter the vulnerability of OLEDs to moisture.

OLEDs produce light by sending electricity through one or more thin layers of an organic semiconductor, which may be composed of any of a variety of materials and as small a as a molecule. The semiconductor is sandwiched between a positively charged electrode and a negatively charged one. These layers are deposited on a supporting surface called a substrate, and protected from exposure to the air by a thin layer of encapsulants (traditionally glass).

The Pohang team demonstrated good electrical, optical, and mechanical performance with flexible electrodes fabricated using graphene, conducting polymers, silver nanowires (AgNWs), and dielectric-metal-dielectric (DMD) multilayer structures.

However, various obstacles still remain with these devices’ durability, conductivity, surface roughness, and fabrication cost. Current flexible substrates and encapsulation methods are being explored, with the goal of reducing cost and processing time, and increasing durability.

Solid State Technology is thrilled to announce that several key industry leaders have joined the Advisory Board for its annual conference and networking event, The ConFab. New members include: Robert Cappel, Senior Director Corporate Marketing, KLA-Tencor; William Chen, Fellow and Senior Technical Advisor, ASE; L.T. Guttadauro, Executive Director, Fab Owners Association; Li Li, Distinguished Engineer, Cisco Systems; Ariel Meyuhas, COO, The MAX Group; Gary Patton, CTO and Head of Worldwide R&D, GLOBALFOUNDRIES and Elton Peace, General Manager North America Regional Operations, Lam Research.

“We are delighted to welcome the new additions to our Advisory Board, each of whom have a unique and valuable insight into the what makes the semiconductor manufacturing industry successful,” said Pete Singer, Editor-in-Chief of Solid State Technology and conference chair for The ConFab. “These individuals will be instrumental is ensuring that The ConFab has an expanded role in the industry and is a “must attend” event for networking and discussing critical economic and manufacturing issues.”

The ConFab 2016 conference program will focus on “The Economics of Semiconductor Manufacturing and Design”. Topics will include:

  • How IoT is Driving the Semiconductor Industry
  • Filling the Fabs of the Future: A Guide to Hot New Applications
  • MEMS Sensor Fusion and More then Moore
  • The Limits of Scaling: Understanding the Challenges of sub-10nm Manufacturing
  • Fabless, Foundries and OSATs: Optimizing the Supply Chain
  • System Integration, Advanced Packaging + 3D Integration
  • China’s New Role in the Global Semiconductor Industry
  • Legacy Fabs and the Resurgence of 200mm
  • The Impact of Continued Consolidation Across the Supply Chain
  • Wearables and Bioelectronics: The Cusp of a Revolution?
  • Tackling Rising R&D Costs in the Semiconductor Industry

The new members will be joining the existing Advisory Board, comprised of David Bennett, VP Alliances, GLOBALFOUNDRIES; Janice M. Golda, Director, Lithography Capital Equipment Development, Intel Corporation; Devan Iyer,,Director Worldwide Semiconductor Packaging Operations, Texas Instruments; Lori Nye, COO/Executive Director Customer Operations, Brewer Science; Ken Rygler, President, Rygler Associates (founder of Toppan Photomasks); Sima Salamati, VP, Fab Operations, imec; Hans Stork, CTO, ON Semiconductor Corporation; Aubrey Tobey, President, ACT International; Geoffrey Yeap, VP of Technology, Qualcomm Inc.; and Abe Yee, Sr. Director, Advanced Technology and Package Development, NVIDIA Corporation.

 The ConFab (June 12-15, 2016) is an executive-level conference and networking event for business leaders from the semiconductor manufacturing and design industry. The event features a high-level conference program, networking events and business meetings with purchasing decision makers and influencers. More information on The ConFab may be found at www.theconfab.com.

The Semiconductor Industry Association (SIA) today announced worldwide sales of semiconductors were $27.9 billion for the month of July 2015, a decrease of 0.9 percent from July 2014 when sales were $28.1 billion. Global sales from July 2015 were 0.4 percent lower than the June 2015 total of $28.0 billion. Regionally, sales in the Americas were roughly flat in July compared to last year, while sales in China increased by nearly 6 percent. All monthly sales numbers are compiled by the World Semiconductor Trade Statistics (WSTS) organization and represent a three-month moving average.

“Global semiconductor sales have slowed somewhat this summer in part due to softening demand, normal market cyclicality, and currency devaluation in some regional markets,” said John Neuffer, president and CEO, Semiconductor Industry Association. “Despite these headwinds, year-to-date global sales through July are higher than at the same time last year, which was a record year for semiconductor revenues.”

Regionally, year-to-year sales increased in China (5.6 percent), Asia Pacific/All Other (1.0 percent), and the Americas (0.8 percent), but decreased in Europe (-12.5 percent) and Japan (-13.3 percent), in part due to currency devaluation. On a month-to-month basis, sales increased in Japan (2.7 percent), China (0.6 percent), and Europe (0.4 percent), but fell slightly in the Americas (-0.3 percent) and Asia Pacific/All Other (-2.5 percent).

“One key facilitator of continued strength in the U.S. semiconductor industry is research, the lifeblood of innovation,” Neuffer said. “SIA and Semiconductor Research Corporation this week released a report highlighting the urgent need for research investments to advance the burgeoning Internet of Things and develop other cutting-edge, semiconductor-driven innovations. Implementing the recommendations in the report will help the United States harness new technologies and remain the world’s top innovator.”

July 2015

Billions

Month-to-Month Sales                               

Market

Last Month

Current Month

% Change

Americas

5.53

5.52

-0.3%

Europe

2.83

2.84

0.4%

Japan

2.57

2.64

2.7%

China

8.13

8.18

0.6%

Asia Pacific/All Other

8.94

8.71

-2.5%

Total

27.99

27.88

-0.4%

Year-to-Year Sales                          

Market

Last Year

Current Month

% Change

Americas

5.47

5.52

0.8%

Europe

3.24

2.84

-12.5%

Japan

3.04

2.64

-13.3%

China

7.75

8.18

5.6%

Asia Pacific/All Other

8.63

8.71

1.0%

Total

28.13

27.88

-0.9%

Three-Month-Moving Average Sales

Market

Feb/Mar/Apr

May/Jun/Jul

% Change

Americas

5.61

5.52

-1.7%

Europe

2.89

2.84

-1.8%

Japan

2.54

2.64

3.8%

China

7.77

8.18

5.2%

Asia Pacific/All Other

8.74

8.71

-0.3%

Total

27.56

27.88

1.2%

Related news: 

Tech, academic leaders call for robust research investments to bolster U.S. tech leadership, advance IoT

Researchers from Holst Centre (set up by TNO and imec), imec and CMST, imec’s associated lab at Ghent University, have demonstrated the world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles. This paves the way to wearable displays in clothing providing users with feedback.

Wearable devices such as healthcare monitors and activity trackers are now a part of everyday life for many people. Today’s wearables are separate devices that users must remember to wear. The next step forward will be to integrate these devices into our clothing. Doing so will make wearable devices less obtrusive and more comfortable, encouraging people to use them more regularly and, hence, increasing the quality of data collected. A key step towards realizing wearable devices in clothing is creating displays that can be integrated into textiles to allow interaction with the wearer.

“Wearable devices allow people to monitor their fitness and health so they can live full and active lives for longer. But to maximize the benefits wearables can offer, they need to be able to provide feedback on what users are doing as well as measuring it. By combining imec’s patented stretch technology with our expertise in active-matrix backplanes and integrating electronics into fabrics, we’ve taken a giant step towards that possibility,” says Edsger Smits, Senior research scientist at Holst Centre.

The conformable display is very thin and mechanically stretchable. A fine-grain version of the proven meander interconnect technology was developed by the CMST lab at Ghent University and Holst Centre to link standard (rigid) LEDs into a flexible and stretchable display. The LED displays are fabricated on a polyimide substrate and encapsulated in rubber, allowing the displays to be laminated in to textiles that can be washed. Importantly, the technology uses fabrication steps that are known to the manufacturing industry, enabling rapid industrialization.

Following an initial demonstration at the Society for Information Display’s Display Week in San Jose, USA earlier this year, Holst Centre has presented the next generation of the display at the International Meeting on Information Display (IMID) in Daegu, Korea, 18-21 August 2015. Smaller LEDs are now mounted on an amorphous indium-gallium-zinc oxide (a-IGZO) TFT backplane that employs a two-transistor and one capacitor (2T-1C) pixel engine to drive the LEDs. These second-generation displays offer higher pitch and increased, average brightness. The presentation will feature a 32×32 pixel demonstrator with a resolution of 13 pixels per inch (ppi) and average brightness above 200 candelas per square meter (cd/m2). Work is ongoing to further industrialize this technology.

The world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles developed by Holst Centre, imec and CSMT.

The world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles developed by Holst Centre, imec and CSMT.

Energy storage players are eyeing emerging opportunities in bioelectronics as wearable, implantable and other medical devices create energy demands and design requirements beyond conventional batteries, according to Lux Research.

Existing battery solutions barely satisfy the demands for increased functionality and power in existing medical devices and may have slowed the shift toward personalized health care in many areas of medicine.

“Developers of energy storage must understand the required application-specific optimization of batteries, based on performance and safety, and desired form factors,” said Milos Todorovic, Lux Research Analyst and lead author of the report titled, “Powerful Medicine: Opportunities for Pairing New Bioelectronics with Innovative Energy Storage.”

“Winning in this race will require a thorough understanding of key technical requirements as well as the knowledge of regulatory and safety implications of bringing new energy storage to the fore,” he added.

Lux Research analysts identified key demands arising from the novel medical technologies, and evaluated energy storage companies on the proprietary Lux Innovation Grid. Among their findings:

  • Li-ion batteries will make rapid strides. Newer lithium-ion batteries will advance both safety and performance, besides extending life span. Compared with today’s best batteries, those that will become available in 2025 will double energy density to over 1,200 Wh/L, more than double specific energy to over 400 Wh/kg, quintuple life span to over 25 years and raise safety standards to “excellent,” from “mediocre to satisfactory.”
  • EaglePitcher, WiTricity, FlexEI are standout companies. On the Lux Innovation Grid, three companies offering diverse technologies stood out as “dominant” in the upper right quadrant. EaglePitcher’s batteries are entrenched in energy storage niches, including military, medical and aerospace; WiTricity leads with its wireless charging technology, a potential life-saving feature; and FlexEI offers contract engineering for custom batteries, with form factors including thin-film and cylindrical cells.
  • Current Li-ion developers lag. On the Lux Innovation Grid, Li-ion developers are clustered mostly in the lower-right “undistinguished” corner, with mediocre technology and business execution, highlighting the need to push beyond today’s incumbent technologies. To succeed, Li-ion battery companies would need to develop flexible form factors without sacrificing energy stored, sharply raise energy density with a push towards next-generation designs like ceramic or polymer solid-state electrolytes, and also enhance safety.

The report titled, “Powerful Medicine: Opportunities for Pairing New Bioelectronics with Innovative Energy Storage,” is part of the Lux Research BioElectronics Intelligence and the Lux Research Energy Storage Intelligence services.