Nanoscale switching promises tinier chips

Researchers at the University of Pittsburgh say they have invented a method to switch electricity on and off at nanoscale dimensions. The invention could lead to the creation of more compact data storage devices by increasing aerial density between data bits on silicon.

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Researchers at the University of Pittsburgh say they have invented a method to switch electricity on and off at nanoscale dimensions. The invention could lead to the creation of more compact data storage devices by increasing aerial density between data bits on silicon.

The project, headed by Jeremy Levy, a professor in the university's School of Arts and Sciences, sought to create a new process to control the connectivity between insulating materials from an electrical conductor to an insulator and then back again.

Levy said the principle could be refined to allow for the development of very powerful and tightly packed ultra-high density storage devices for logic and memory devices.

The results of the Nanoscale control of an interfacial metal-insulator transition at room temperature project were published last week on the website of Nature Materials. The paper will also be published in the April print edition issue.

Levy said the process of switching electrical properties at nanometric scales required that researchers refine the connection point between two insulators – a crystal of strontium titanate and a 1.2 nanometre-thick layer of lanthanum aluminate.

The researchers used an atomic force, microscopic conducting probe to create wires measuring less than 4 nanometres wide – and in isolated areas almost down to a nanometre – to place between the two materials. Levy noted the process of using the probe closely resembles how an Etch-A-Sketch drawing pad works, which he confesses helped shape his research.

Levy said the discovery is important for developers of storage systems because the number of bits that one can store on a chip depends on how close they are placed side-by-side.

"There are many storage applications this could apply to," said Levy. "In semiconductors, we were able to show that we could show 'transistor-like action' with these wires. We think we have the elements of being able to make transistors, as well as memory elements at a scale that is much smaller than existing silicon is capable of."

To illustrate his research, Levy noted that magnetic storage bits placed 50 nanometres apart corresponds to 1 terabit of storage per square inch. But if bits could be spaced 5 nanometres apart, then available storage capacity could be boosted to 100 terabits per square inch.

The idea for the project came during Levy's visit to the University of Augsburg in Germany in 2006, where he saw researchers enable the boundary separating the strontium titanate from the 1.2 nanometre lanthanum aluminate switch between a conducting and insulating state. But that process could not be instituted toward localised areas, setting the stage for Pitt's research work.

Levy said the physical model of the university's nano-sized discovery requires further testing. He noted other areas of development for the technology could include the creation of a single electron transistor or to work with applications.

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