RESEARCHERS MASTER SELF-ASSEMBLY OF NOVEL NANODOTS
31 August 2004 - National Science Foundation

Because the method works with a variety of materials and may drastically reduce imperfections, the new procedure may also bolster research into extremely hard materials and efforts to develop ultra-dense computer memory.

The researchers are working with an industry partner to apply the technique to development of next-generation light-emitting diodes, the small, bright lights seen in traffic signals and luxury automobile brake lights. The experimental LEDs are already more efficient than existing devices, potentially lasting decades and using a fraction of the power of fluorescent bulbs.

Jagdish Narayan and Ashutosh Tiwari, both of North Carolina State University and the National Science Foundation's Center for Advanced Materials and Smart Structures, invented the new materials and manufacturing processes.

They announced their findings in the September, 2004, issue of Nanoscience and Nanotechnology.

Narayan and Tiwari used a pulsed excimer laser to create conditions under which nickel self-assembles into 3-D, ordered arrays within aluminum oxide and titanium nitride matrices. Applying similar techniques to gallium nitride and zinc oxide, the researchers are hoping to further improve the efficiency of their LED devices.

Computer applications are further away, as many additional hurdles need to be cleared before the nanodots become actual chips. However, since every nickel-metal nanodot could theoretically store a single bit of information, the researchers believe that a one-inch chip using that technology could eventually store 10 Terabits of data.

According to the researchers, the chip would theoretically have several hundred times more storage than conventional microchips of the same size. Five Terabits could fit on, coincidentally, a nickel. If nanodot memory chips eventually succeed, the entire contents of the Library of Congress could fit onto a pocket full of "change."

From the researchers:
"The grand challenge is to build, efficiently and reliably, a nanostructure using nanounits. But nature doesn't like to create nano-sized units of uniform size, they are at a higher energy state.", Jagdish "Jay" Narayan, John C. C. Fan Family Distinguished Chair in Materials Science at North Carolina State University and Director, NSF Center for Advanced Materials and Smart Structures

"Controlled processing and self-assembly in three dimensions are required because you cannot create these structures and then assemble them. They are too small. So to be able to use this technology, you must have self-assembly and it must be 3-D", Jagdish "Jay" Narayan

"In the past we could make only one-layer structures and 3-D self-assembly wasn't possible. We couldn't control the medium. Now, with this development we can control the medium and do 3-D self-organization. More importantly we can change the size in different layers and can change the functionality at different depths", Jagdish "Jay" Narayan

"The research provides the basic framework for nanostructured materials for information storage, spin transistors, single-electron transistors and hydrid devices, superhard coatings, and novel biomaterials", Jagdish "Jay" Narayan

"In the 6-10 nm dots created so far, we have the ability to control the spin patterns, the spin is what stores the bit of information. Assuming a 7nm magnetic nanodot will store one bit of information, we can achieve over 10 trillion bits per square inch, which is close to 500 times the existing storage density.", Jagdish "Jay" Narayan

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