November 28, 2008: Science fiction writers have long envisioned sailing a spacecraft by the optical force of the sun’s light. But, the forces of sunlight are too weak to fill even the oversized sails that have been tried. Now a team led by researchers at the Yale School of Engineering and Applied Science has shown that the force of light indeed can be harnessed to drive machines — when the process is scaled to nano-proportions.
Their work opens the door to a new class of semiconductor devices that are operated by the force of light. They envision a future where this process powers quantum information processing and sensing devices, as well as telecommunications that run at ultra-high speed and consume little power.
The research, appearing in the November 27 issue of Nature, demonstrates a marriage of two emerging fields of research — nanophotonics and nanomechanics – which makes possible the extreme miniaturization of optics and mechanics on a silicon chip.
The energy of light has been harnessed and used in many ways. The “force” of light is different — it is a push or a pull action that causes something to move.
“While the force of light is far too weak for us to feel in everyday life, we have found that it can be harnessed and used at the nanoscale,” said team leader Hong Tang, assistant professor at Yale. “Our work demonstrates the advantage of using nano-objects as “targets” for the force of light — using devices that are a billion-billion times smaller than a space sail, and that match the size of today’s typical transistors.”
Until now light has only been used to maneuver single tiny objects with a focused laser beam — a technique called “optical tweezers.” Postdoctoral scientist and lead author, Mo Li noted, “Instead of moving particles with light, now we integrate everything on a chip and move a semiconductor device.”
“When researchers talk about optical forces, they are generally referring to the radiation pressure light applies in the direction of the flow of light,” said Tang. “The new force we have investigated actually kicks out to the side of that light flow.”
The researchers showed that when the concentrated light was guided through a nanoscale mechanical device, significant light force could be generated — enough to operate nanoscale machinery on a silicon chip.
The light force was routed in much the same way electronic wires are laid out on today’s large scale integrated circuits. Because light intensity is much higher when it is guided at the nanoscale, they were able to exploit the force. “We calculate that the illumination we harness is a million times stronger than direct sunlight,” adds Wolfram Pernice, a Humboldt postdoctoral fellow with Tang.
“While this development has brought us a new device concept and a giant step forward in speed, the next developments will be in improving the mechanical aspects of the system. But,” says Tang, “the photon force is with us.”
Category Archives: LEDs
November 25, 2008: Research chemists at the University of Warwick have devised an process that cheaply covers small particles of polymer with a layer of silica-based nanoparticles. The final result provides a highly versatile material that can be used to create a range of high performance materials, such as self-healing paints, and clever packaging that can be tailored to let precise levels of water, air, or both pass in a particular direction.
The research, led by Stefan Bon of Warwick’s Department of Chemistry, has created a “soap-free emulsion polymerization process” which makes colloid particles of polymer dispersed in water and in one simple step introduces nanometer-sized silica based particles to the mix. These silica-based nanoparticles (about 25nm in size) coat the polymer colloids with a layer, “battering” it like a fish battered in breadcrumbs.
This process creates a very versatile polymer latex product. Application examples include scratch-resistant paints in which the scratches heal themselves; also, polymer-based packaging which will allow water or air to pass through the packaging in tailored ways. The resultant rough textured spherical shapes also lend themselves to the creation of sheets with polymer that present much more surface area than usual allowing more efficient interaction with other materials.
This new process can already be produced on a mass scale with currently used industrial equipment, the researchers claim.
A multi-layered polymer colloid taken with a transmission electron microscope.
November 24, 2008: Hague Corp., a solar technology and quantum dot manufacturing company, has appointed Ghassen E. Jabbour to the position of chief science officer, to lead development and characterization of thin-film quantum dot solar cell products at recently acquired Solterra Renewable Technologies.
Jabbour is the director of flexible and organic electronics development at the Flexible Display Center (FDC) and has been a professor of chemical and materials engineering at Arizona State University since 2006. He is also the technical advisory board leader on Optoelectronic Materials, Devices, and Encapsulation at FDC. He has been selected to the Asahi Shimbun 100 New Leaders of the USA and has received the Presidential Award for Excellence from the Hariri Foundation in 1997. His research experience encompasses flexible-roll-to-roll-electronics and displays, smart textile, moisture and oxygen barrier technology, transparent conductors, organic light emitting devices, organic and hybrid photovoltaics, organic memory storage, organic thin film transistors, combinatorial discovery of materials, nano and macro printed devices, micro and nanofabrication, biosensors, and quantum simulations of electronic materials. He has authored and co-authored more than 300 publications and has edited several books and symposia proceedings involving organic photonics and electronics, and nanotechnology.
“We are extremely pleased to have someone as talented and accomplished as Dr. Jabbour join our team as CSO,” said Stephen Squires, president and CEO of Solterra, in a statement. “Ghassen’s deep understanding of nanotechnology and photovoltaics will drive our future product development.”
Cadmium selenide quantum dots manufactured by Solterra Renewable Technologies.
by Griff Resor, Resor Associates, SST editorial advisory board
Nov. 18, 2008 – In spite of the global economic crisis, the recent Flat-Panel Display International (FPDI) event (Oct. 29-31, Yokohama, Japan) drew a large crowd all three days. Not many US or European people came to Japan to see the latest in flat-panel display technology, but lots of Asian people were here, including a large Taiwan contingent and an increased (vs. 2007) China contingent. Almost every major maker of displays participated, showing off their largest, fastest, and best looking displays including plasma, LCD-TVs, OLED, e-ink, and other novel display technologies, though a few key exhibitors (e.g. Canon, Corning) did not have booths. Gen 10 Equipment was pictured — a few huge sputtering targets were in the exhibition hall — but there was not much “new” in equipment.
Notebook and monitor ultraslim displays.
3D: The next big demand driver?
Digital signage looks like the next “big” market; ≥82-in. LCD displays look great as programmable signs. These now include 4× more pixels than full HDTV, roughly 4000 × 2000 × RGB, or 24 million pixels. The result is a very crisp, almost paper-like display of information in full color. Live action and live update is of course possible. Many of these digital signs also include multi-touch films, so users can center the display on the item of interest to them, and then zoom in for added detail.
Digital signage using 4X FHD Plasma display.
TV remains the largest display market, but people are still searching for what will replace the demand for flat HDTVs once this market is saturated. After SID in May and now FPDI in late October, it is clear 3D TV will be a very big replacement market. This year’s FPDI held special technical sessions on the topic of 3D and the future of TV, both of which highlighted advances in 3D technology.
Hollywood has discovered that 3D versions of new movies are bringing in 3× the revenue of 2D versions; families are coming to theaters to see 3D versions in greater numbers and are paying a premium. Over 40 films are now in Hollywood’s 3D pipeline; today, about 2000 theaters can project 3D movies, and in two years this will increase to over 8000 theaters, thanks to technical advances in digital cameras, computer graphics, video editing software, 3D projectors, and movie screens. 3D technology market leader RealD (Dolby is No. 2) has also worked closely with movie studios to understand what range of depth perception impresses audiences without causing stress — everyone is determined not to repeat the past mistakes made with 3D.
Hollywood wants to move 3D into the home, too, calculating that ~10× revenue can be generated from home DVD sales. At FPDI, Panasonic, Philips, and RealD presented their ideas for home delivery. All use existing cable and DVD delivery paths, but each company has its own compression method and chip that shrinks the 3D data volume so it fits into the present delivery paths, and in the TV set there is a matching decoding chip that expands the data to 3D. This looks good, but means we may revert to DVD recordings that are set maker specific. No one at FPDI was talking about a 3D standard.
Both the RealD and Dolby technologies require special glasses to view the 3D left and right images; these systems use time-sequential full HD images. Faster plasma and LCD displays are required. Plasma may beat LCD to this market, since plasma displays already can shift their output very quickly. However, the ubiquity of LCD-TV almost guarantees that once again LCD innovations will be made — for example, a smaller gap between glass sheets and very fast LED backlights.
LCD-TV is already moving in the right direction. At this year’s FPDI several manufacturers exhibited 240Hz frame rates, double the 120HZ which was last year’s big advance. In each case, fast graphic chips in the TV set generate the added frame data.
4X FHD ultra-definition LCD display with 120Hz frame rate.
Many TV makers exhibited “glasses-free” 3D systems, which use a lenticular array, much like the old 3D postcards. Philips is working to deliver this system for digital signage in 2010. Lenticular 3D technology requires many extra pixels. For each viewing position, two sets of pixels are needed; to provide three or five viewing positions, 6-10 separate sets of pixels are needed at the same time. Philips will use 4X FHD digital signage displays. Clearly more pixels will be needed in the future. I looked at several of the lenticular 3D displays, and found the 3D image is not easy to see in most cases. My first impression is that time-sequential 3D displays may win out for TV applications, where many viewing positions are needed.
LED backlights, e-inks, MEMS, OLEDs, Gen 10, R2R
LED backlights were everywhere. Using LED backlights, TV makers can provide better color gamut (105% of NTSC), better contrast (darker blacks), and peak brightness that is not possible with CCFL technology. At the same time, the power consumed has been reduced nearly 2×. A 32-in. HDTV now only uses 50W of power, and a 42-in. HDTV only needs 85W. TVs that use LED backlights can be just 10mm thick, 2× thinner than prior units, which saves display material and shipping cost. Many of these changes have been done to improve the carbon footprint of flat TVs.
OLED displays were shown in many more booths at this year’s FPDI, though forecasts still show real growth is a few years in the future. Samsung Mobile Display (a merger of SEL and SDI display) had the largest OLED, a 40-in. HDTV. OLED displays look great; I think it is their superior black. They are also just 1.0mm thick.
The largest OLED TV, a 40-in. HDTV, from Samsung Mobile Displays.
Several novel display technologies were exhibited. E-ink books keep improving; their blacks are almost as good as ink on paper, but their whites remain quite gray. US-based Pixtronix demonstrated their MEMS type display, which uses micro-shutters to control light through the display to reduce cell phone power needs by 4×. Futaba showed their FED (field emission displays). These have to work in sunlight, in cars and trucks, so some compromises on color accuracy have been made. Shipla demonstrated a 1.0m × 3.0m sign using an array of very small tubes. Their sign was huge, but image contrast was not great.
Ohara glass had on display a huge Gen 10 mask blank, about 1625mm × 1775mm × ~20mm. Nippon Sheet Glass demonstrated rolled thin glass, for future use in roll to roll processing. Several equipment companies had pictures of roll-to-roll equipment, but this was not getting much attention.
Nippon Sheet Glass exhibit of rolled glass. Left front says 100m of 100μm-thick glass; right front says 20m of 50μm-thick glass (50μm = 0.002-in.)
In summary, FPDI 2008 showed improvements in flat display size, resolution, speed, color, and contrast. Digital signage will provide a near-term market for the largest, highest-resolution displays, including direct-view 3D from Philips. LCD-TVs continue to improve, showing faster response, less blur, better color gamut, and less power use, as the back light technology shifts to LEDs. Novel display technologies continue to get noticed, but have not gained significant market share. Equipment and materials suppliers have responded to the need for Generation 10 equipment. And among it all, everyone is trying to figure out what this global economic downturn might mean for this business. — G.R.
November 17, 2008: Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have demonstrated experimentally and theoretically that the surface plasmon resonances of metal nanoparticles in a periodic array can have considerably narrower spectral widths than those of isolated metal nanoparticles. Further, as the optical fields are significantly more intense in a periodic array, the method could improve the sensitivity of detecting molecules at low concentrations.
While researchers have known that a group of nanoparticles could be used to increase signal levels for sensor applications, the electromagnetic interactions between the particles have often been overlooked. A team led by Ken Crozier, John L. Loeb associate professor of the Natural Sciences at SEAS, showed that by spacing a nanoparticle array appropriately, the interactions between nanoparticles can be optimized.
The study, published in the November 3 issue of Applied Physics Letters, was carried out by Yizhuo Chu, Ethan Schonbrun and Tian Yang under the direction of Professor Crozier, all of SEAS. “We used numerical electromagnetic simulations to design nanoparticle arrays exhibiting narrow surface plasmon resonance peaks and intense optical fields, and checked our predictions experimentally,” said Crozier.
To do so, Crozier and his team fabricated the nanoparticle arrays using electron beam lithography on glass substrates. By measuring the optical transmission of collimated beams of white light through the arrays, the team found that their experimental results confirmed their original theoretical predictions of sharp plasmon resonance peaks.
“The narrow peaks occur when the product of the nanoparticle spacing and the refractive index of the surrounding medium approximately matches the plasmon resonance wavelength of a single nanoparticle,” explained Crozier.
Over the past several years, Crozier and his colleagues have helped to advance the field of plasmonics, harnessing its ability to confine electromagnetic fields to deep sub-wavelength dimensions for spectroscopy, sensing and optical manipulation. The larger field enhancement demonstrated in their latest finding could be important for further refining surface enhanced Raman spectroscopy and for improving biosensors.
The work was supported by the National Science Foundation, the Defense Advanced Research Projects Agency (DARPA), the Charles Stark Draper Laboratory, and the Harvard Nanoscale Science and Engineering Center.
Nov. 11, 2008 – The ranks of top semiconductor suppliers in terms of sales is missing a lot of memory these days, but that means those who are left are enjoying better growth than the industry average, particularly those in the fabless/foundry segment, according to recent rankings from IC Insights.
Four of the top 20 companies in the rankings have enjoyed >20% growth for the year so far (1Q08-3Q08) vs. the same period a year ago, led by Qualcomm (27%, $5.14B) and Broadcom (25%, $3.44B). Eleven firms in all outpaced the top 20’s average 6% growth — a number dragged down by the last firm on the list, Hynix (-27%, $5.22B) — and all of them outpaced the industry’s overall 4% mark.
Top sales through the year is of course Intel ($26.83B, 7% growth), followed by Samsung ($16.76B), TI ($9.57B, -3%), Toshiba ($8.71B, -6%), and TSMC ($8.64B, 25%). Samsung’s 15% growth was by far the best out of the memory firms on the list (Micron 4%, Toshiba -6%, and Hynix -27%), and Qimonda, Elpida, and Spansion fell off the top 20 list entirely. It took 1Q-3Q sales of >$3B to make the list this year.
IC Insights projects these top 20 firms to post an average -8% sales decline in 4Q08 (growth-pacer Qualcomm is eyeing a -28% sequential slide), and close out the full year with combined sales of $182.2B, up 2% over the past year, in line with the overall worldwide semiconductor market.
Top 20 semiconductor sales leaders, 1Q08-3Q08 (US$M). Source: IC Insights
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Top 20 semiconductor sales leaders ranked by growth, 1Q08-3Q08 (US$M). Source: IC Insights
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(November 6, 2008) EINDHOVEN, the Netherlands — DuPont Teijin Films joined the systems-in-foil program of Holst Centre, a research initiative of the Flemish and Dutch research centers IMEC and TNO. DuPont Teijin, as a major substrate vendor, completes the ecosystem of industrial players for its systems-in-foil program line.
Flexible, large-area, low-cost electronics are seen as having huge market potential. Studies indicate that the organic electronics market will exceed the size of the silicon semiconductor market as it is today. One of the two program lines at Holst Centre in the Netherlands focuses on processes and technologies for systems-in-foil, such as large-area printing, electrodes, and barriers. A.o. organic LEDs (OLEDs) are used to demonstrate the progress and possibilities of the investigated technologies.
Dupont Teijin Films joins the Holst Centre program on flexible organic lighting and signage, bringing in knowledge on foil production. The aim of this Holst Centre program is to design and optimize OLED device concepts and processes that are compatible with roll-to-roll (R2R) fabrication. The project brings together equipment and materials suppliers with system integrators and device manufacturers around a well-defined roadmap. The agreement was signed between Dupont Teijin Films and TNO, coordinator of the activities.
Others in the systems-in-foil program include Philips, Solvay, Akzo Nobel, and Agfa.
DuPont Teijin Films is a 50/50 joint venture (JV) between DuPont and Teijin Limited.
For more information, visit www.holstcentre.com.
Nov. 5, 2008 – Intel Corp. regained market share in the latest quarterly tallies of microprocessor (MPU) sales that it had lost to rival AMD a year ago, and overall sales were still healthy Y-Y despite slowing PC demand, according to data from iSuppli.
Intel accounted for 80.4% of global MPU revenue, up fom 80.1% in 2Q08 and 78.7% in 3Q07, with growth mainly due to the notebook computer sector, notetd Matthew Wilkins, principal analyst of computing platforms for iSuppli, in a statement. AMD, meanwhile, dropped to 12.1% share, up slightly from the 12.0% it had in the previous quarter but down from the 13.9% it held a year ago. The sales include not just x86 PC MPUs but also RISC and other types of general-purpose MPUs. And both companies’ share gains in 3Q came at the expense of smaller suppliers, which slid to 7.5% share vs. 7.9% in 2Q, a shift attributed to the global financial crisis.
There have been signs of weakening PC demand in 3Q, but iSuppli noted that its own calculations suggest healthy growth in shipments vs. a year ago (~12%-14%), led by he notebook segment; the firm expects full-year 2008 MPU unit growth of 12.5%.
The OptoCooler HV series, a new class of RoHS-compliant high voltage, heat pumping thermoelectric coolers, has been optimized for standard circuitry and power requirements. The OptoCooler HV14, the first module in the series, has been designed for the optoelectronics and telecom industry. OptoCooler HV14 operates at a maximum voltage of 2.9V and can pump 1.7 watts of heat at 85°C in a footprint of 2.8 mm2. The module can create a temperature differential of up to 51°C between its hot and cold sides, making it suitable for the cooling and temperature control of optoelectronic devices such as laser diodes and high-brightness LEDs.
At the core of the module is the thermal copper pillar bump, an electronic device made from thin-film thermoelectric material embedded in flip chip interconnects. Thermal bumps act as solid-state heat pumps and add thermal management on the surface of a chip or other electrical component. By reducing the size of the thermal bump by 75%, the company has increased voltages by 300% and reduced the current draw by the same proportion. The net result eliminates the need for special voltage conditioning and reduces the overall electrical current required to operate the device. Nextreme Thermal Solutions, Inc., Research Triangle Park, NC, www.nextreme.com
By Paul Collander, Poltronics, Inc.
At the recent Advanced Packaging Conference at SEMICON Europe in Stuttgart, Germany, (October 7-9, 2008) Fran