GAITHERSBURG, Md., Nov. 12, 2003 — Carbon nanotubes are a hundred times stronger than steel, right?
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That factoid has been reported so often that few realize that such superstrength is predicted by calculations, not by any direct measurement of the force it takes to pull an actual nanotube apart. James Von Ehr, chief executive and founder of Zyvex Inc., made this observation about nanoscale measurements last week in a National Institute of Standards and Technology (NIST) workshop on developing standards and road maps for nanoelectronics.
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Organized by the Institute of Electrical and Electronics Engineers (IEEE), the meeting gathered more than 60 scientists, executives and government representatives from around the world. Some of the corporate players on hand included Eastman Kodak Co., Motorola Inc. and Samsung, as well as organizations such as the Office of Naval Research and the American Society of Mechanical Engineers.
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One of the fundamental questions raised: What do voltage, resistance and current mean at the infinitesimal scale of individual molecules and atoms?
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Nanotech researchers described how difficult it is to measure a single device such as an individual nanotube or wire. Scale the problem up to precise, industrial-strength metrology on millions or billions of similar structures in a display or computer memory chip, and you begin to appreciate the scale and shape of the standards conundrum.
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The first day of the conference was devoted to assessing where more accurate and standardized ways of measuring could advance nanoelectronics and materials. The second was the kickoff meeting for IEEE’s Working Group P1650, which is drafting standards for testing the electrical properties of carbon nanotubes.
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The milewide scope of the first day revealed that developing standards for nanoelectronics will be challenging because the field itself is all over the map, figuratively and geographically. Cliff Lau, the new president of IEEE’s Nanotechnology Council, reported that beyond the United States and Japan, research is flourishing in such disparate countries as India, Mexico, Latvia and Turkey. Lau insisted that nanotechnology, as a global phenomenon, needs better mechanisms for international collaboration to make sure everybody is “talking about the same thing.”
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In nanoelectronics alone, research and development is exploding through divergent scientific disciplines and on multiple fronts — molecular switches, spintronics, carbon nanotube transistors, silicon nanowires, and quantum dots, among them. Several participants noted that in many instances chemists and biologists, not electrical engineers, are the ones who have to measure extremely small electrical characteristics of materials.
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The challenge of crafting standards is further complicated by the fact that building blocks, such as carbon nanotubes, are often synthesized by different processes that create structures with widely varying properties, making protocols even more elusive.
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One thing is clear: There are countless characteristics that companies and researchers would like to measure in predictable, repeatable ways at the nanoscale, such as the exact sizes of nanostructures or the quantum effects at work in individual nanoparticles.
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But here’s the rub: The tools to gauge such ultrafine nano attributes don’t yet exist, much less accepted procedures for taking them. Still, there was consensus that measurement methods should be globally agreed upon so that science and industry don’t end up contending with competing standards or scales. One engineer from outside the United States noted ruefully that NASA still doesn’t fully work on the metric system.
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Indeed, how different standards-setting organizations in the United States, Europe and Asia might coordinate their efforts remained a wide-open question. In the United States, for example, NIST encourages and supports standards, but does not set or enforce them. Some participants also questioned whether IEEE was the appropriate body to create standards in the realm of nanomaterials, an area a bit afield of its electrical engineering roots.
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Nevertheless, Jonathan Tucker, from toolmaker Keithley Instruments Inc., said that developing instruments and standardized nanometrics is more than an issue of academic interest. “Customers are asking us how they can make these measurements now,” he said.
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Motorola’s Dan Gamota, chairman of IEEE’s nanotech standards committee, said that essential industry-endorsed standards exist for manufacturing cell phones and other high-volume products his company makes.
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Charles Gause, director of manufacturing for Luna Nanomaterials, said that production standards that allow buyers to verify and sellers to guarantee materials are the lifeblood of high tech.
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Gause spent eight years earlier in his career growing silicon wafers. “The product had to be virtually defect-free or you were out of business,” he recalled. His current company, based in Blacksburg, Va., produces buckyballs with atoms of three metals caged inside for a variety of applications.
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Yet an industrywide standard does not yet exist for characterizing buckminsterfullerenes (aka buckyballs) that would allow customers to know exactly what they were buying.
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As for Von Ehr’s question of just how strong carbon nanotubes really are, after he posed it, one quick-witted workshop attendee shot back: “Well, they better find out before they go and build that space elevator out of them.”