George Malliaras and his colleagues recently had a bright idea—literally. As director of the Cornell University NanoScale Facility, he is among several researchers working on nanolamps—light-emitting microfibers no larger than a virus. The technology promises a new generation of flexible displays that can be integrated into a variety of products and perhaps even woven into clothing. "Here we have devices made out of fiber," Malliaras said. "You talk about textile, and your mind doesn't necessarily go to electronic devices."
Hot Or Hype?
Whether it's tiny fiber lamps, molecular-level memory circuits, or any of the hundreds of other small-scale innovations currently being investigated, nanotechnology has emerged as one of the most important research developments of the 21st century. Often compared to fundamental technological breakthroughs like the steam engine, the transistor, and the Internet, nanotechnology promises a new generation of innovative, power-saving, and performance-boosting electronic devices. It will also help electronics continue on its march toward ever smaller and denser devices.
"We're going to have to have some fundamental change in the way that we put electronic devices together if we're going to increase their performance in the years ahead," said Andrew Maynard, emerging-nanotechnologies chief science advisor to the Woodrow Wilson International Center for Scholars, a non-partisan think tank created by Congress. "Because we try to cram so much stuff into such small spaces, nanotechnology is the only way we're going to find new solutions."
Vahé Mamikunian, a senior analyst at Lux Research, a market research firm for emerging technology, predicts that nanomaterials will be a $13 billion market by 2014 while sales of nano-enabled products will become a $1.82 trillion market by that same year. "As nanotechnology matures, it will open up a new paradigm of electronics where electronic products will become even more ubiquitous," Mamikunian said.
Lofty sales projections and comparisons to breakthrough technologies of the past led a number of critics to accuse nanotechnology boosters of hyping the field's prospects. Mamikunian acknowledges that while some researchers may be inflating their projects' importance to attract more venture capital or government funding, his research finds that plenty of hard-nosed business cash is flowing into the field. "There has been an almost equal amount of corporate funding," Mamikunian said. "That's not something that is generally vocalized."
According to Mamikunian, big businesses ranging from electronics giants like Intel and Motorola to chemical powerhouses such as BASF and Bayer are intensely interested in nanotechnology. "Companies of these sorts are looking at nanotechnology as a way to further the progress of the industries they are active in," he said. "They're serious about nanotechnology."
Cellular Level
Molecular-level storage is one promising area of nanotechnology. In 1959, physicist Richard Feynman predicted that it should be possible one day to store all of the Encyclopedia Britannica on the tip of a needle.
Although this goal hasn't yet been reached, joint nanotechnology research at the University of California at Los Angeles (UCLA) and the California Institute of Technology (Caltech) may give storage technology a big shove in that direction. These institutions' researchers created a memory circuit the size of a white blood cell that contains the capacity to store the Declaration of Independence. The device's 160-kbit capacity makes it the densest memory circuit ever created.
Lit Up
On the other side of the country at Cornell University, scientists are continuing to investigate nanotechnology's potential as a cheap and efficient electronic light source. Made from a compound based on the metallic element ruthenium, the researchers' nanolamps are smaller than the wavelength of the light they emit.
Using a technique called electrospinning, the researchers spin the fibers from a mixture of the metal complex ruthenium trisbipyridine and the polymer polyethylene oxide. The fibers give off orange light when excited by low voltage through micropatterned electrodes, like a tiny light bulb (Fig. 2). The synthetic fibers are just 200 nm wide. Malliaras compares the production technique to pouring syrup onto a pancake located on a spinning table.
As the "syrup" (a solution containing a metal complex-polymer mixture in solvent) is poured, it forms a spiral pattern on the "pancake," a substrate containing micropatterned gold electrodes. A high voltage between a microfabricated tip and the substrate ejects the solution from the tip and forms a jet that's stretched and thinned. As the solvent evaporates, the fiber hardens and lays down a solid fiber on the substrate.
Malliaras notes that the tiny light-emission devices can be made with simple fabrication methods. Compared with traditional high-resolution lithography methods, electrospinning requires almost no fabrication and is simpler to do. "What this work shows is that you can have form factors, materials, and processing metals that are traditionally not associated with electronic devices, yet can be used to yield electronic devices," he said.
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