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Nanomaterial Offers New Heat Management for Advanced Electronics

Researchers at GE Global Research under a DARPA contract have announced a new thermal material system for dissipating heat in advanced electronics that is far more effective than traditional copper.

According to the Dr. Tao Deng, the lead researcher on the project at GE, the new material is a phase-change material that was used in a prototype as a substrate for a chip.

With the all the work that is currently being done in the development of novel nanoscale materials for heat management of electronics (see, here and here) it seems that GE has set aside electronics for aviation as a market they are targeting with this technology.

In Dr. Teng’s blog discussing the technology a good deal of the description is devoted to how it performs in high gravity environments.

"In demonstrations, the prototype system has functioned effectively in a variety of electronics and application environments. We also subjected it to harsh conditions during testing and found it could successfully operate in extremely high gravity applications. More specifically, the prototype has operated in conditions that simulate more than 10 times the normal force of gravity! By comparison, this gravity force is more than four times greater than what someone would experience on the Mission Space ride at Disney."

I don’t recall any other new materials that were intended for heat management in computer chips spending so much time highlighting their functionality in high G’s without mentioning much in the way how much better their heat management is.

This preoccupation along with the DARPA contract leads me to suspect that we will likely see this in aerospace before we see in laptops. 

 

Report on Potential Risks of Nanotechnology in Electronics Needs a Second Draft

I have encountered both hopeless ideologues and blinded cheerleaders on either side of the nanotechnology and toxicity debate, and in my experience it is the environmentalists who are just unreachable.

Like Pavlovian Dogs, they see the term “nanotechnology” and bark back “What about the environment?”. They don’t really discern between microscopy tools and nanoparticles, never mind delineate among the vast amount of different nanoparticles. They just know that nanotechnology is untested and being foisted upon them as unsuspecting consumers by some evil industry.

At least with the nanotech cheerleaders you can temper their enthusiasm if you explain the situation a little bit. After all greed has as its close relative fear, but ideology’s closest kin is ignorance. There is a little you can do to overcome that, certainly the force of argument doesn’t help.

In both observing this debate and covering the issue, I have not come across any organization that has presented more faulty thinking on the subject than the Silicon Valley Toxics Coalition (SVTC).

So egregious is their thinking in these matters that I am torn between believing that it must be a deliberate misrepresentation of the issues or they just don’t know or understand them. The latest insult to our collective intelligence is their white paper entitled “Nanotechnology in Electronics: The Risk to Human Health”.

Let’s take a look at it. It starts out with a definition of nanotechnology in the first sentence that is not too bad as these definitions go. But in the next sentence manages to confuse the concept of molecular nanotechnology with the nanomaterials variety that they are no doubt railing against. This is just an introduction to the confused thinking we find further.

For instance, in the second page we are provided a glossary. At the top of the list, I guess because the list is alphabetical, are “brominated flame retardants” (BFRs). Okay, but why? What does this have to with nanotechnology or nanoparticles? In fact, if anything, it demonstrates why we should hardly be concerned about nanoparticles in electronics when 2.5 million tons of BFRs are used annually in polymers.

After presenting BFRs and explaining they have been shown to be detrimental to both human and environmental health, we are given “engineered nanoparrticles” next in the glossary. A somewhat facile definition is provided “ENPs are so small they cannot be seen with a regular light microscope” but no detrimental effects are attributed to them, except, of course, that it is listed right under BFRs. Guilt by association? I am beginning to lean towards deliberate misrepresentation.

On the same page, we get the question “How Small is Small?” (Poorly informed pieces such as these spend a lot of time providing definitions, no doubt because of the author’s need for them). And for the first time, we get the term that is supposed to connote the Evil Empire: The Nanotechnology Industry. I challenge anyone, including misguided environmentalists, to tell me what the nanotechnology industry is, or is supposed to be.

Of course, having a monolithic nanotechnology industry planning to do us harm for profit is a lot more satisfying and can produce amusing banners that say stuff like this: “Nano, it’s not green, it’s totalitarian”. Sigh.

Next in the SVTC report we get the questions of why nanoparticles are important and why they would be used in electronics. The answers are more or less accurate, but it’s not clear why the use of nano lithium iron oxide in rechargeable batteries is presented so ominously when it is explained that they may replace conventional batteries in laptops and cell phones.

Are conventional batteries, filled as they are with all sorts of toxic materials, any less of a threat? Or maybe the SVTC wants to eliminate laptops and cell phones all together? I ask this because when I recently suggested that nanotech research might eliminate the need for batteries in cell phones, I was met with the Pavlovian response: What about the environment?

Just as a note to the SVTC the next time you put one of these together you should know that a majority of today’s Li-ion batteries already use nanofibers.

Finally, by the fifth page we get an answer to the question: How is nanotechnology used in electronics? And who is their source for an answer to this question: The Project on Emerging Technology (PET). Now I almost feel sorry for the SVTC, bad data in bad data out.

Since the PET list offers little explanation of their, shall we say, less than rigorous nanotech product list, the SVTC doesn’t present any specific examples of how nanotechnology is used in electronics either. We are just told that it is found in nearly every form of consumer electronics. You can claim that, but can you show it?

Just to add insult to injury they present “molecular” electronics. Really? Again, this is just poorly informed. Why add molecular electronics to your list of boogey men unless you had no idea of how it really fit into the universe of nanotechnology and electronics. I am leaning back towards not knowing or understanding.

Look, I am in favor of the most rigorous research into determining the risks of nanoparticles in electronics and a host of other applications and products. But if I may take the exhortation at the end of this report and turn it around it somewhat: Be an informed environmentalist. 

Nanotech Research into Improving Cladding of Nuclear Fuel Rods

Last July, Dr. Hongbing Lu, a nanomaterials expert and researcher at the University of Texas at Dallas, received nearly $900,000 from the US Department of Energy (DoE) to begin to look at how it may be possible to improve the materials used for cladding nuclear fuel rods

At the time of the announcement, it seemed the main benefit to come from the research would be a reduction in fuel burn rate and increasing efficiency of nuclear power plants. But now with the unfolding nuclear disaster in Japan one can’t help but wonder if improving the cladding materials of the nuclear rods might have helped avoid leakage when the rods were temporarily exposed.

Lu was planning to first investigate how cracks propagate in the materials and then ultimately to start looking at various materials that could avoid this kind of cracking.

“We’re working on a very general simulation methodology that can be applied to that kind of environment,” Lu said. “It’s more than just crack growth. We need to understand how the material behaves under extreme pressure, temperature, corrosion and irradiation. With the methodology we’re using, we’re taking all of those factors into consideration and incorporating material behaviors into some mathematical models to describe them under very complicated conditions.”

At the time of the article announcing the DoE research grant, Lu expected that the materials research they were conducting would not only be beneficial for the materials cladding the nuclear fuel rods but also for other parts of a nuclear power plant.

Nanotechnology Could Make Batteries in Mobile Devices Obsolete

Beyond making mobile phones and other mobile devices flexible enough to wrap around your wrist, I have been a strong proponent of efforts to improve the battery life of these mobile gadgets

There have been a number of announcements recently reporting on work that improves the li-ion batteries used in mobile phones, or efforts to reduce the amount of energy used by these devices through the use of steep-slope transistors and thereby lengthen the battery life.

It is in this latter area of  seeking to lower power consumption in these devices that  we have our latest breakthrough to extend the battery life of mobile phone from hours to weeks.

Researchers from the University of Illinois’s Beckman Institute for Advanced Science and Technology, led by electrical and computer engineering professor Eric Pop, have reported in Science that they have used carbon nanotubes to control bits and lower power switching in phase change materials (PCM).

Just as a bit of background on PCM, one of the major commercial initiatives with the material in memory applications was the joint venture between Intel and STMicroelectronics with their Swiss-based Numonyx, which Micron Technologies acquired last year. PCM compares quite favorably with NOR-type flash, memory NAND-type flash memory, and RAM or EEpROM. Cost is still high compared to DRAM and read speed is not as good as DRAM, but unlike it DRAM it is non-volatile. You can read more about PCM memory here.

But what the researchers recognized was that one of the drawbacks with PCM memory was that high programming currents have made it difficult to realize low power operation. The researchers overcame this drawback by replacing metal wires with carbon nanotubes.

In a press release prepared by the University of Illinois, graduate student Feng Xiong, the first author of the paper, explains, “The energy consumption is essentially scaled with the volume of the memory bit,” says Xiong. “By using nanoscale contacts, we are able to achieve much smaller power consumption.”

The way the system works is that bits are created by putting a small amount of PCM in the a nanoscale gap located in the middle of a carbon nanotube and then by applying just small currents to the nanotube they can switch the tube on and off.

According to the abstract in Science, the researchers were able to achieve “programming currents as low as 0.5 μA (SET) and 5 μA (RESET), two orders of magnitude lower than state-of-the-art devices.”

What this may translate to for your mobile phone is that a smart phone will consume so little energy that it may not even need a battery but could run on its own thermal or mechanical energy. (Battery manufacturers are not going to like that part).

“I think anyone who is dealing with a lot of chargers and plugging things in every night can relate to wanting a cell phone or laptop whose batteries can last for weeks or months,” Pop is quoted as saying in the University of Illinois press release.

New Technique Allows for Single Atomic Layer Patterning of Graphene

Last month when I suggested an imagined rivalry between graphene and molybdenite for replacing silicon in future transistors, I was pleased with the comments the piece received.

It would seem some are looking more towards the memristor replacing the transistor all together rather than just looking at how to improve transistors, and considering that a paper in IEEE Computer Magazine inspired an article in the New York Times maybe this will be the case.

But getting back to the transistor and graphene, it seems that researchers at Rice University have stumbled upon a way to pattern a single atomic layer of graphene.

The research, which was published last week in the journal Science, provides a technique for controlling the number of layers that are removed when patterning graphene, which previous techniques could not achieve.

“One cannot make a layer thinner than a single atomic layer. That’s it,” explains James Tour, Rice's T.T. and W.F. Chao Chair in Chemistry in the video below. “We have hit the bottom.” 

According to Ayrat Dimiev, a postdoctoral scientist in Tour's lab, the discovery of the patterning technique was a complete accident. “We had no idea that we would be removing a single carbon layer from graphene,” he says in the video. “We were trying to reduce the graphene in a new way using zinc and hydrochloric acid.”

While the patterning technique may not have a bottom on the vertical dimension, the researchers recognize that the ideal would be to achieve the same precision on the horizontal dimension. 

So graphene can be imbued with a band gap and it’s possible to achieve single atomic layer patterning so when can we expect to see someone making an electronic device out of the stuff?

High-throughput Analyzer Provides Size and Concentration Measurements of Nanoparticles

I have detailed in the past how biologists have felt forlorn in the world of imaging on the nanoscale.

Dejected biologists have continued to seek out some tools to aid them in seeing the nanoscale world. This search found some sympathetic researchers at the University of California Santa Barbara.

In an article over at Nanowerk, which delves into the details of the research that was first published in Nature Nanotechnology, the lead researcher on the project explains the motivation for developing what is being described as a “high-throughput label-free nanoparticle analyzer”.

"Our collaborators informed us of the significant need for similar technologies for particle analysis on the nanoscale for studying blood and other potential clinical applications, and we set to work," explains Jean-Luc Fraikin, the first author of the paper. "Only once we became more deeply involved in the project did we begin to appreciate the broader context for this work, given the range of applications for which nanoparticles in this size range are being developed, and the lack of practical sizing technologies that were available."

The device they developed is able to measure both the size of nanoparticles and their concentration in solution at a rate of 100,000 particles per second. This stands in stark contrast to the other methods that have been available for measuring these metrics, namely averaging and electron microscopy. With averaging there was no way of determining the varying sizes of the particles and electron microscopy was time consuming and expensive.

"The low-cost, scalable fabrication method, as well as the simple readout electronics, make this analyzer potentially useful in a wide range of applications," noted Fraikin in the Nanowerk article.

The analyzer is a micro-fluidic design with a micro channel that leads the analyte through a sensor consisting of “two voltage-bias electrodes and a single, optically lithographed readout electrode embedded in the microchannel.”

"Together, these components form a fluidic voltage divider that yields wide-bandwidth electrical detection of particles as they pass through the nanoconstriction," Fraikin explains in his Nanowerk interview. "The sensing electrode is embedded in the channel between the fluidic resistor and the nanoconstriction. As a particle enters the nanoconstriction, it alters the ionic current and, because of the voltage division between the fluidic resistor and the nanoconstriction, changes the electrical potential of the fluid in contact with the sensing electrode."

It would seem the time is right for having a cheap and easy-to-use device for measuring the size and concentration of nanoparticles in all sorts of solutions, not just biological ones. If Geoffrey Ozin is correct in his estimation that nanomaterials are at a saturation point where some more measurement of what we have is needed, then this could be tool to help in that regard.

But as the Nanowerk article points out, “While the nanoparticle analyzer discussed here measures two very basic physical properties of nanoparticles – their size and concentration in solution – many other characteristics of nanoparticles, such as surface charge, surface roughness, detailed particle shape and electric or magnetic polarizability are critical to their applications and will require tools for the high-throughput measurement these properties as well.”

Nanotech-enabled Products Face Numerous Obstacles on the Way to Market

It is with great pleasure I can report that I read a really first-rate article on nanotechnology from the mainstream press. It comes from the Irish Times and is based around an interview with Prof Peter Dobson of Oxford University, who had been in Ireland in early February for the Nanoweek conference

I had the pleasure of meeting Prof. Dobson in his role as Academic Director of Oxford University’s Begbroke Science Park when I was helping to give some visiting researchers a tour of UK research facilities. With no other motivation than to share his knowledge and experience, he gave us all some rich insights into how it can be possible to lift mere lab research into really making an impact.

The same too goes for this interview in the Irish Times. What is so intriguing about Dobson’s thoughts on nanotechnology and its commercialization is that he remains one of the few who is both a first-rate scientist with both an academic and industrial background and an accomplished businessman.

For me, the greatest lessons are often learned from failures rather than successes, so it is in his explanation of a recent failure of one of his spinout companies Oxford Biosensors that I found a good one. 

“That is a terribly sad story,” he recalls of Oxford Biosensors in the Irish Times article. Adding it was “too disruptive for any licence deal” and the costs of gaining regulatory approval proved overwhelming. 

“We developed a sensor for substances, in a pinprick of blood, which would be markers of cardiac risk. We were within eight or nine months of having a commercial product on the market, but we ran out of money.”

There are all sorts of ways for a company to fail, especially one that is using an emerging technology, but running out of money seems to be a common complaint. But what can’t be overlooked is that established players in the market, even if their technology is comparatively inferior, are not going to make it easy for anyone to introduce a technology into the market that will make their product obsolete.

As I was quoted in an article on the pages of Spectrum when discussing Nantero’s long-awaited nanotube memory chip: ”It is competing with large companies. Samsung, for instance, has created a $4 billion market for themselves with flash memory. Do you think they are going to idly sit by while some start-up says they are going to make that business obsolete? Not likely; they have their own approach, which they are developing in conjunction with University of Cambridge.”

The important lesson here to me is that even if there is strong market pull for your technology, even if you can bridge any regulatory obstacles, you still have to contend with entrenched market giants who just aren’t going to let you walk off with their business.

Nanostructured Material Promises to Double Li-ion Battery Capacity

Nanosys, the Palo Alto, CA-based nanomaterials company, which has long been touted as the IP King of Nanotech with over 500 patents for nanomaterials, has made an announcement recently about a nanomaterial to improve Li-ion battery capacity.

Yimin Zhu, director, battery & fuel cell, at Nanosys, made the announcement while speaking at the IEEE Bay Area Nanotechnology Council lunch forum last month. While the article is light on specifics, it seems that the company has developed a silicon-based, “architected” material that fills in the voids of the carbon anode material matrix.

According to Nanosys’s claims, the material “remains intact and fully functional after 100% DoD cycle testing.” It also “demonstrated a >2× capacity improvement using 10% additive in a Li+ battery anode.”

I managed to glean from the graphic below that the new material will increase density to 300Wh/kg from 170Wh/kg of a graphite coating, and do so with the addition of cutting costs.

While going through this article and Nanoys' website to get some more information, I noticed one annoying bit about the company's latest marketing copy is the term “architected”. Why create a word like this when there are already quite reasonable real words that would suffice: designed, structured, or fabricated. Just annoying.

Anyway, Nanosys is still in the business of making nanostructured materials (or should that be nanoarchitected materials?) and finding industry partners to apply these materials to some device.

Last year, at the CES show they were demonstrating how a nanomaterial they had developed could make the color of LED lights more vivid. On their website, they have a business unit called “LED backlighting”, but I haven’t heard whether they have started shipping that material to LED device manufacturers in bulk. 

According to the article in which Zhu is quoted, “volume revenue shipments are expected in 2011” for the material that promises to boost Li-ion battery capacity. I would like to hear later how it all works out because over the years I have developed some serious doubts about companies that are just selling nanomaterials rather than actual devices and other products.

Hydrogen Fuel Cells for Automobiles Look More Feasible with Nanostructured Storage Material

I have been skeptical of claims that nanotechnology was going to help usher in the hydrogen economy. This skepticism is not without reason.

When it turned out that carbon nanotubes were in fact pretty poor at storing hydrogen and their storage capacity was closer to 1wt% in practicality than the lofty 50wt% storage that some research had claimed, I became somewhat jaded.

But there is a new, shiny knight that is challenging my cynicism. It’s a UK-based company called Cella Energy.

I came to know of them through their recent winning of the Shell Springboard Awards, which earns them £40,000 (approximately US$65,000) and a press release.

Now, while some have waxed poetic about hydrogen fuel cells powering cars of the future, others have whispered that the complete lack of any infrastructure for transporting and delivering hydrogen was a pretty steep obstacle, not to mention the extraordinary cost of isolating hydrogen.

But it is in the former barrier that Cella has offered a solution. It seems they have developed a way of trapping hydrides in a nanoporous polymer, or microbeads, which allows the hydrogen to be stored at low pressure and ambient temperatures.

Just to give you a sense of how difficult it has been to store hydrogen (and imagine this system strapped to your automobile), the pressure needed for storing hydrogen has been typically “700 times atmospheric pressure (700bar or 10,000psi) or super-cooled liquids at -253°C (-423°F).” That could be described as a ticking time bomb traveling with you underneath your car.

With the Cella system since there is no special cooling system required or pressurized storage cylinders the hydrogen storage packaging will look pretty much like a typical fuel tank found on cars today.

Cella has not made any dramatic claims about percentage of hydrogen storage capacity like the carbon nanotubes hullabaloo. At the moment, they say that their materials are performing at “6wt% weight percentage of hydrogen, but Cella is now working with complex hydrides that store hydrogen at up to 20wt%.” According to the company website, this exceeds “the revised 2009 Department of Energy targets to produce hydrogen storage materials that would compete with gasoline.”

This all sounds great, but perhaps what is most intriguing about this technology is that the microbeads can be added to conventional fuels in today’s engines and would lower the emissions of those vehicles “to meet the new EU Euro 6 standards for emissions with minor vehicle modifications.”

Apparently, the nanoporous polymer is cheap to produce and Cella claims to be ready to ramp up production, it has applications for both hydrogen fuels cells cars or if that never gets off the ground it makes a fine fuel additive for reducing emissions. So, what’s not to love?

I’m not really sure, but I am bit troubled by their remarks that £40,000 is going to tip them over the edge and now they can ramp up industrial scale production. I am sure they were just be grateful for the prize money, but if they are sincere I can’t see how that amount does much more than pay their staff a month’s salary.

Could Super Conducting Graphene Quantum Dots Lead to Solid-State Qubits?

Quantum computers are sometimes referred to as the Holy Grail of computing, or maybe the Philosopher’s Stone of computing might be another appropriate medieval reference to a nearly unattainable quest. In any case, while some outfits have claimed they have achieved fairly significant quantum computer prototypes despite being met with skepticism, creating a quantum computer that can calculate something beyond what a kid in elementary school can factor has proven difficult.

One of the fundamental issues researchers have faced in developing quantum computers has been the problem of getting the computers to maintain more than a few quantum bits (or qubits). One of the more promising ways of getting beyond a mere seven qubits has been the use of quantum dots.

Now researchers at the University of Illinois led by Nadya Mason have brought a new wrinkle into this field of research. The research, which was initially published in the journal Nature Physics, was looking at what happens when a normal conducting material like a metal or graphene is sandwiched between two superconducting materials and observing the interface of the materials.

While it has been observed previously that normal metals in these instances take on the characteristics of the superconductor material when current is passed through it (namely, that it too will pass electron pairs through it rather than a single stream of electrons), the Illinois researchers by working with graphene quantum dots were able to better understand the fundamental physics at play: Andreev bound states (ABS).

To date, ABS have proven to difficult to both measure and observe. At is at this point that the researchers developed a novel method to isolate individual ABS by connecting probes to quantum dots made from graphene. As quantum dots do they confined the confined ABS into discrete energy states, which permitted the researchers to not only measure the ABS but to manipulate them.

"Before this, it wasn't really possible to understand the fundamentals of what is transporting the current," Mason said. "Watching an individual bound state allows you to change one parameter and see how one mode changes. You can really get at a systematic understanding. It also allows you to manipulate ABS to use them for different things that just couldn't be done before."

The concurrence of the two nanomaterials, graphene and quantum dots, along with the superconducting material made the breakthrough possible. 

"This is a unique case where we found something that we couldn't have discovered without using all of these different elements – without the graphene, or the superconductor, or the quantum dot, it wouldn't have worked. All of these are really necessary to see this unusual state," Mason said.

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Nanoclast

IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

 
Editor
Dexter Johnson
Madrid, Spain
 
Contributor
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
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