Two nanotechnology researchers say they have achieved a breakthrough that could fit the contents of 250 DVDs on a coin-sized surface and might also have implications for displays and solar cells.
The scientists, Ting Xu of the University of California at Berkeley and Thomas Russell, of the University of Massachusetts Amherst, have discovered a way to make certain kinds of molecules line up in perfect arrays over relatively large areas.
Russell and Xu have discovered a new way to create block copolymers, chemically dissimilar polymer chains that join together by themselves. Polymer chains can join up in a precise pattern equidistant from each other, but research over the past 10 years has found that the patterns break up as scientists try to make the pattern cover a larger area.
Xu and Russell used commercially available, man-made sapphire crystals to guide the polymer chains into precise patterns. Heating the crystals to between 1,300 and 1,500 degrees Celsius (2,372 to 2,732 degrees Fahrenheit) creates a pattern of sawtooth ridges that the two scientists used to guide the assembly of the block copolymers. With this technique, the only limit to the size of an array of block copolymers is the size of the sapphire, Xu says.
Once a sapphire is heated up and the pattern is created, the template could be reused, Xu says.
The two scientists say they achieved a storage density 15 times the density of past solutions, with no defects. With this density, the data stored on 250 DVDs could fit on a surface the size of a US quarter, which is 25.26 millimeters in diameter. It might also be possible to achieve a high-definition picture with 3-nanometer pixels, Xu says. Another possibility is more dense photovoltaic cells that capture the sun's energy more efficiently.
The new technology could create chip features just 3nm across, far outstripping current microprocessor manufacturing techniques, which at their best create features about 45nm across. However, actually applying the technique to CPUs would pose some challenges, such as the need to create random patterns on a CPU, Xu says.
Such a leap ahead in storage density could alter either the amount of content that a person could carry with them or the quality of media delivered on discs, says Nathan Brookwood, principal analyst at Insight64. For example, it might allow movies to turn into holograms, he says.
Ultra-high-definition displays have less practical potential, according to IDC analyst Tom Mainelli. The image and video standards of today, including those used in HDTV, couldn't take advantage of a display with 3nm pixels, he says. And when it comes to monitors, price is king.
"You could see how there would be a value to that level of precision (in an area like medical imaging) ... but are we talking about a $10,000 display?" Mainelli asks.