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Nanoribbons Break New Ground in Memory Storage Density

Researchers from Germany, Switzerland and Italy have demonstrated that turning graphene into nanoribbons using V2O5 nanofibers as etching masks not only dramatically improves their memory storage density over silicon-based chips but also surpasses carbon nanotubes and graphene in their transition times.

The research, which was initially published in the Wiley journalSmall, demonstrated that by depositing V2O5 nanofibers on top of graphene and then etching it with argon ion beam they were able to produce graphene nanoribbons that were less than 20 nm wide. This process also produced ribbons with smoother edges than are typically found with lithography techniques, resulting in devices made from them that have better performance characteristics.

The key to the nanoribbon’s memory storage density is that small memory cell. And according to Roman Sordan of the Politecnico di Milano, and one of the researchers on this project, that grapehene nanoribbons shrink these down to 10 nm scale.

“Indeed, the area of our new memory cell is so small that it allows for a very high storage density,” Sordan said in a story published by nanotechweb.org. “We thus expect that graphene nanoribbon memory chips will allow Moore's law to continue for the foreseeable future.”

According to Sordan in the same article, the device produced from these graphene nanoribbons has a transition time three orders of magnitude shorter than those devices made from either carbon nanotubes or graphene.

In addition, Sordan believes the versatility of these memory cells will open differenct application areas. “They can be used as both static random access memories and nonvolatile flash memories cell for ultrahigh storage density applications,” he says in the article.

Now that memory has been addressed the researchers are going to look at how their nanoribbons can be applied to digital logic gates. “We have already made graphene logic gates but think that those made from nanoribbons will be better,” says Sordan.

IBM Goes for World Record in "Noise-Free" Labs

Nearly imperceptible changes for either man or machine in temperature, movement and noise can be catastrophic for executing accurate measurements on the nanoscale.

For this reason, IBM’s new Nanotechnology Center at its Zurich, Switzerland research campus has devoted approximately 10% of the new facility’s $60 million overall cost to constructing six rooms for different microscopy tools. Not only are the labs the most isolated from noise and movement of any other similar labs in the world, but have also gone beyond the capabilities of the most sensitive detection equipment currently available to detect either movement or noise.

This week I had the opportunity to tour IBM’s still unfinished Nanotechnology Center (they expect to have the facility operational by the first half of 2011) and get a look into their new “Noise-free”  labs , in which they are planning to get their first microscopy tool by the first quarter of 2011.

When deciding to go out for a record like the most “noise-free” lab in the world, they sure didn’t make it easy for themselves with the location. While the location does keep the Nanotechnology Center on the same campus of the research facility that IBM opened back in 1956, it is less than 200 meters from a heavy rail track and it would seem by my own estimates to be a good deal closer than that to a four-lane highway.

The benchmark for the IBM scientists who designed and engineered these labs from scratch was the NIST laboratories. Now the IBM researcher who was instrumental in the design, engineering and overseeing of the construction of these facilities, Dr. Emanuel Lörtscher, and who gave the assembled European journalists a presentation on the facilities, said that the NIST facilities they were informally competing against were located in a more remote location, making IBM's achievement all the more remarkable.

In any case, what the IBM team has accomplished is significant. Every conceivable detail was addressed. For instance, rather than simply using steel-reinforced concrete a special plastic was used as the rebar. 

As mentioned, the design and engineering of this facility was done in-house at IBM Zurich, and since one of the stated goals of IBM is to deliver an additional $20 billion in revenue by 2015 and bring its earnings per share to $20 by the same year from its current level of $10 EPS, I thought I would ask as an aside whether they were considering selling this developed design and engineering skill as a service, the response I got was, “We’re considering it.”

Federal Reserve Measures Impact of Nanotechnology on Electronics

The Federal Reserve, that extra-governmental entity that has run US monetary policy for the last century, has presented some fascinating interpretations of our economic circumstances in the recent past. The most glaring examples of this has been the idea put forth from its two most recent Chairman, Ben Bernanke and Alan Greenspan before him, that there was no housing bubble. Oops.

That’s why I found the most recent announcement from one of the twelve regional Federal Reserve Banks, in this case the one in Dallas, that it was going to be hosting a one-day seminar on how nanotechnology is going to impact electronics, somewhat disturbing. "Sizing Up Nanotechnology: The Economic Impact of Nanoelectronics" as its called will assemble experts from around the country to speak on December 3 in Texas and have them address:

  • What radical innovations might remove the circuit size constraints facing today’s semiconductor industry?
  • How will nanoelectronics drive productivity, output and export growth in the U.S.?
  • What conditions are needed for the industry to maximize its potential?

I think I have an inkling of what these talking points might mean, but I have to confess phrases like “remove the circuit size constraints” have me scratching my head. And I have to ask what “industry” are they referring to when they ask what conditions are needed for it to maximize its potential.

However, I really became confused when they proffered that “Nanoelectronics has the potential to replace the semiconductor.” I guess I just don’t know what they mean by “nanoelectronics”, or for that matter “semiconductor”.

But I am sure the assembled experts will clear this up. I just trust that they can avoid the reading of the economic tea leaves that led them to believe there was no housing bubble.

Is There a Connection between Nanotechnology and the So-Called Hydrogen Economy?

Nanotechnology has been held out as the missing element for making fuel cell use commonplace since the field first started to get news coverage outside of a select group of scientific journals.

I remember back to around 2001 when there was a real expectation that NEC would be offering commercially a fuel cell-powered laptop shortly. After a couple of years of getting “next year” as the status update, the story just faded away and it became clear that it wasn’t going to happen.

It may satisfy some to lay the blame for this failure to commercialize fuel cell-powered laptops at the feet of nanotechnology (in this case it was the use of nanohorns) but it is more likely the case that toting around a laptop through airport security with a half a liter of methanol attached to it wasn’t going to pass muster.

Then there was the hope that carbon nanotubes (CNTs) would be useful in storing hydrogen. There were supposedly some claims that CNTs had greater than 50wt% storage capacity but it is now generally accepted that the figure is closer to 1wt% in practicality.

Okay, nanohorn-based direct from methanol fuel cells just weren’t practical and CNTs just are not that great at hydrogen storage. But there are always catalysts, right? Huge surface area and small volume have always been appealing for improving catalysts, and the same is true for those catalysts used in fuel cells.

But improved catalysts hardly addresses the real problems for fuel cells. Let’s face it the stumbling blocks for fuel cells has been the cost of producing hydrogen and, especially in the case of portable fuel cells (like those used in an automobile), the lack of an infrastructure for supporting a so-called hydrogen economy.

With this as a backdrop, I saw a headline, “Nanotechnology and the Hydrogen Economy” so I had to check it out. I found the video I’ve posted below.

Oddly, there is no mention of how nanotechnology will enable a hydrogen economy, but nanotechnology and hydrogen economy are discussed independently.

We are given a definition of nanotechnology (thanks, we really don’t have enough of those) and we are told how one photon from the sun has just enough energy to split a water molecule into its constituent parts. How we are supposed to harness that energy for this purpose is discussed with a smile and the quip, “The energy is there we just have to figure out a way to use it.”

Yeah, I  guess so. What this has to do with nanotechnology would be of some passing interest. Maybe we can get that in the next video from its producers.  

Ice Lithography on the Nanoscale Moves Up a Notch in Complexity

Researchers at Harvard University are moving beyond patterning simple nanowires with ice lithography to creating more complex nanodevices.

The Harvard researchers, who are part of the Harvard Nanopore Group, including Daniel Branton and Anpan Han, published research back in 2005 that demonstrated that they could successfully execute nanometer-scale patterning with ice.

Now the researchers have reported in the November 1, 2010 online edition of Nano Letters that they can use ice lithography to produce nanodevices made from single-walled carbon nanotubes.

According to interviews for both Branton and Han in a Nanowerk article, the research provides a method for scaling up the applications for CNT-based nanodevices.

One of the ways in which the ice method provides scaling potential is by replacing atomic force microscopes (AFM) with scanning electron microscopes (SEM) in the mapping of the carbon nanotubes.

“Although not generally spelled out in publications, it is well known among the cognoscenti that nanotubes are contaminated or damaged by mapping their location in an electron microscope" Han is quoted as saying in the Nanowerk article. "To avoid contaminating or damaging, CNTs are often mapped by atomic force microscopes (AFM). But AFM is extremely slow. SEM mapping through ice is much faster and could be automated."

Ice lithography also eliminates a problem when using polymer-based resists, the resist residue affectionately known in the semiconductor industry as ‘scum’. While the scum is often less than one or two nanometers thick, that’s enough to obscure partially a carbon nanotube or to bosure completely a single layer for graphene. The process of getting rid of the scum (oxygen plasma) also manages to remove any carbon-based nanocomponents, according to Han. 

The ice lithography technique doesn’t leave any residue, which will likely improve the quality of the resulting nanodevices.

Now that the researchers have moved their research from patterning of simple nanowires to nanodevices, they see the next steps to be in the direction of making 3D nano- and graphene-based devices with this ice lithography technique. But the fundamental research into understanding the mechanisms behind ice lithography remains incomplete.

“Finally, we need to achieve a deeper understanding of the mechanisms behind ice lithography, about which we still know very little," says Branton.

National Nanotechnology Initiative Opens Its Strategy to Public Input

After the President’s Council of Advisors on Science and Technology (PCAST) presented earlier this year its 10-year review of the National Nanotechnology Initiative (NNI), and then shortly after that the White House sought the public’s input on the future strategy for nanotechnology development, it seems that the NNI itself is going to have a go itself at getting the public’s input on what it should be doing.

As of yesterday, November 1, the NNI is seeking public comment for thirty (30) days on its current draft of a strategic plan, which is accessible at the NNI Strategy Portal.

While I initially dismissed this idea of getting the public’s input on what the US nanotechnology strategy ought to be, I was soon turned around when I heard some of the highly informed, creative and comprehensive ideas that were collected by PCAST. Of course, once these serious ideas were presented, the PCAST chairperson then summarily dismissed them, instead seeking some quick and easy answers. But nonetheless as long as there are serious ideas out there, and some serious people listening, it couldn’t hurt.

I suppose the NNI has been a viable target for critics over the years, primarily for its less than overwhelming attention to the environmental, health and safety (EHS) concerns surrounding nanotechnology. An issue for which the NNI has been trying to address with a 300% increase in EHS funding from 2006 to its latest request for 2011.

But despite this the NNI remains a benchmark for nearly every government-led nanotechnology initiative that has sprouted up since (in 2007 the estimate ran to 35 of countries announcing nanotechnology programs) and rightly so I would argue.

While some governments have laid claim to have first set aside government funding for nanotechnology research, they haven’t really distinguished themselves since with a particularly well-run programs.

Now that it appears the US nanotech strategy will place an increasing emphasis on developing applications from the basic nanotechnology research that has been funded over the past 10 years, and give more attention to the EHS concerns that may arise from these commercial applications, I think the NNI is more or less on the right track and maybe some helpful input from the public could sand the edges. We’ll see.

Steep Slope Transistors Provide Benefit of Longer Battery Life for Mobile Phones

On Wednesday I covered the announcement from Ecole Polytechnique Fédérale de Lausanne (EPFL) and IBM that they along with host of other European research institutes were intending to develop better transistors that would eliminate the wasted current that drips through transistor gates.

The project has been dubbed Steeper based on its intentions to create steep slope transistors that exhibit an abrupt change when switching between on and off states.

I focused primarily on its addressing of the issue of vampire energy consumption and how this project could account for much greater energy conservation.

Oddly, considering my recent preoccupation with improving mobile phone batteries and rechargeable batteries in general, I neglected to point out that one of the side benefits of conserving power in electronic devices is that the batteries will last longer. This was pointed out to me in a flurry of tweets on Twitter claiming “Cellphone Battery Life to Improve 10x Thanks to Nanotechnology”.

In my defense for not pointing this out in my original blog entry, I should note that the technology will not improve battery technology, but just improve the electronic devices that the batteries are charging so that they use less energy and drain less power from the batteries.

EU Project Aims at Stemming the Tide of Wasted Energy for Our Electronic Devices

I have made the point on a couple of occasions that when nanotechnology is applied to energy its major impact right at the moment is in helping to conserve energy rather than helping in generating it.

This I am sure is not appealing to those who cheerlead for solar power or fuel cells, but nanotechnology’s significant contribution to the world’s energy woes at the moment is more about better insulation.

Along these lines, Ecole Polytechnique Fédérale de Lausanne (EPFL) and IBM announced a major research initiative, dubbed Steeper, that aims to improve the energy efficiency of the electronic devices we use every day.

Maybe you’re not getting as excited about this as some new advance in photovoltaics, but you should. To give you the magnitude of the problem, here is some data from a press release sent out for the announcement.

“According to the International Energy Agency (IEA), electronic devices currently account for 15 percent of household electricity consumption, and energy consumed by information and communications technologies as well as consumer electronics will double by 2022 and triple by 2030 to 1,700 Terawatt hours -- this is equal to the entire total residential electricity consumption of the in US and Japan in 2009.”

Finding a way to reduce this energy consumption is a big deal and it seems the scientists in a recently formed consortium of research institutes and universities in Europe will be employing nanotechnology to reach a solution.

The nanotechnology of which we speak will come in the form of semiconducting nanowires that the researchers will be investigating along with tunnel field effect transistors (TFETs) to not only close the gates of transistors more tightly but also see if they can find a method for opening and closing the gate for maximum current flow and fewer turns.

To give you a sense of how serious this project is they started it back in June and are just now letting people know what they’re doing. And some of the key individuals in the project are speaking confidently about its prospects.

“Our vision is to share this research to enable manufacturers to build the Holy Grail in electronics, a computer that utilizes negligible energy when it's in sleep mode, which we call the zero-watt PC," Professor Adrian Ionescu of the Nanolab at EPFL is quoted as saying in the above referenced article.

"By applying our collective research in TFETs with semiconducting nanowires we aim to significantly reduce the power consumption of the basic building blocks of integrated circuits affecting the smallest consumer electronics to massive, supercomputers," says Dr. Heike Riel, head of the nanoscale electronics group at IBM's Zurich research facility.

Batteries the Size of a Grain of Salt Enabled by Nanowires

I have made clear my interest in seeing nanotechnology employed so as to improve the current state of batteries.

Let us make no mistake, nanotechnology, primarily in the form of nanofibers, is being used in batteries today. In fact it was estimated as far back 2005 that nearly 60% of batteries used nanofibers.

But what I am after, and I think your average consumer is looking for too, are rechargeable batteries for our portable devices that will last longer than a few hours (laptops) or a day or two (mobile phones and MP3 players), and instead will last weeks or months on a charge, and also significantly increase the number of times we can recharge those batteries without them progressively getting worse at holding that charge.

So I was intrigued by research funded by DARPA that looked as though it was pushing battery technology a bit further.The results of a portion of that research conducted at UCLA were reported last week at the AVS 57th International Symposium & Exhibition, which was held at the Albuquerque Convention Center in New Mexico, (The abstract of the presentation can be found here).

The UCLA researchers were involved in developing an electrolyte that would be used in batteries the size of a grain of salt and would not only be able to power portable electronic devices but also micro- and nano-scale devices.

To do this the name of the game is working in three dimensions rather than two in order to increase the energy densities but shrink the size of the battery. In this case, with the electrolyte element, the UCLA researchers coated “well-ordered micro-pillars or nano-wires -- fabricated to maximize the surface-to-volume ratio, and thus the potential energy density…” 

While the overall DARPA research is still at its early stages, it now has an electrolyte and other components, such as the electrodes, already developed. But nobody at this point has started to join the various components to create an actual battery. So, I’m still waiting.

Does Hype Surrounding Nanotechnology Even Matter?

There is often an odd schizophrenic nature to articles that set out to bemoan the phenomenon of nanotechnology hype. The latest article of this variety over at Industry Week is a typical example. It starts out explaining how the market has been hyped and then proceeds for the majority of the article to list all the new and unexpected ways nanotechnology is impacting commercial products.

We get the usual complaints of how molecular-level manufacturing is still 10 years away (perpetually so it would seem) disappointing those who thought we would building products from the bottom-up by now, the $1 trillion market number by 2015 is hype and is closer to $26 billion, according to one market research firm and environmental and regulatory concerns are poised to tip over the picnic cart.

As bad as it all appears at least we can take comfort in the fact that Industry Week has taken a real (and welcomed) interest in nanotechnology by running near monthly columns from Scott E. Rickert, who pens their “Taking the NanoPulse” column, which I have commented on before.

Plus I feel myself in agreement with much of their perspective on the state of nanotechnology’s commercial development. However, when I take a step back it always has this initial cautionary tone and then seems to exhort us towards its bright and limitless future.

I guess I am just as conflicted as they are. Nanotechnology is no doubt already being integrated into commercial products to such an extent that in the article, BASF spokesman, Rudiger Iden, explains, “Now that nanotechnology has progressed as a cross-technology used in many products across the company, there is no longer a way to place a figure on nano-related investment.” It’s just too pervasive to separate it out it would seem.

But at the same time we get a pretty regular stream of anti-hype articles like this one, or those who reduce the entire nanotechnology enterprise to “vaporware”. So what brings on this odd split personality when we look at nanotechnology’s prospects?

It’s probably just because it’s prospects still lie so much in the future. We look at the future with both dread and longing. On the one hand, fear that it won’t meet our expectations or be something far worse and on the other hand hope that all our worries will be quelled and better days are ahead. 

So, what of the state of nanotechnology? Has it not met our expectations? Well since “nanotechnology” has been foisted upon as an investment opportunity or worse an industry, I suppose it was bound to disappoint us.

But I am becoming more and more content with just the notion that our ability to manipulate and examine materials at the nanoscale is going to have an enormous impact on the world, and already is doing so. And best of all, will likely do it in ways that we can’t even imagine right now.

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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
 
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Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
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