Vanadium oxide bronze: A replacement for silicon in microchips?

September 14, 2012, University at Buffalo

Nanowires crafted from vanadium oxide and lead. These wires' unique electrical properties could make them ideal for use in switching components of computers. Image by Peter Marley, with colored added.
(—Few modern materials have achieved the fame of silicon, a key element of computer chips and the namesake for Silicon Valley, home to some of the world's most prominent technology firms.

The next generation of computers, however, may not rely so much on silicon.

University at Buffalo researchers are among scientists working to identify materials that could one day replace silicon to make computing faster. Their latest find: A bronze whose unusual electrical properties could increase the speed at which information is transferred and stored.

In Advanced Functional Materials, the research team reports that they have synthesized nanowires made from vanadium oxide and lead.

The reason that these nanowires are so special is that they perform a rare trick: When exposed to an applied voltage near room temperature, the wires transform from insulators that are resistant to carrying electricity to metals that more readily conduct electricity.

When exposed to an applied voltage near room temperature, these nanowires transform from electrical insulators to electrical conductors. Each wire is about 180 nanometers wide. Image by Peter Marley, with color added.

Each of these two states—insulator and metal—could stand for a 0 or 1 in the that computers use to encode information, or for the "on" and "off" states that the machines use to make calculations.

"The ability to electrically switch these between the on and off state repeatedly and at faster speeds makes them useful for computing," said study co-author Sambandamurthy Ganapathy, a UB associate professors of physics.

"Silicon computing technology is running up against some fundamental road blocks, including switching speeds," added Sarbajit Banerjee, another co-author and a UB associate professor of chemistry. "The voltage-induced phase transition in the material we created provides a way to make that switch at a higher speed."

As with other nanomaterials, the health and environmental impacts of the nanowires would have to be investigated before their widespread use, especially since they contain lead, Banerjee cautioned.

Banerjee and Ganapathy oversaw the study, which appeared online Aug. 17 in the journal . UB chemistry PhD student Peter Marley was lead author. Other contributors include Peihong Zhang, a UB associate professor of physics, and students from Ganapathy's research group.

One intriguing characteristic of the material they synthesized is that it only exhibits valuable in nano-form. That's because nanomaterials often have fewer defects than their bulkier counterparts, Banerjee and Marley explained.

In the case of the lead vanadium oxide nanowires, the wires' distinctive structure is crucial to their ability to switch from an insulator to a metal.

Specifically, in the insulator phase, the position of the lead in the nanowires' crystalline structure induces pools of electrons to gather at designated locations. Upon applying a voltage, these pools join together, allowing electricity to flow freely through them all and transforming the material into a metal.

"When materials are grown in bulk, there's a lot of defects in the crystals, and you don't see these interesting properties," Marley said. "But when you grow them on a nanoscale, you're left with a more pristine material."

Explore further: Windows that block heat only on hot days: New research brings us closer

More information: DOI: 10.1002/adfm.201201513

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1 / 5 (1) Sep 14, 2012
Our present state of Nano-science is very exciting. Who can imagine all the things we might be on the verge of discovering? It reminds me of the early days of chemistry, when we first discovered atoms, and the explosion of new discovery that opened up.

When I was in college chemistry it always bothered me that so much of what we know about it is purely experimental observation. I still wonder if we will ever reach an understanding of materials that allows us to predict the properties like the one above, rather than blindly mixing stuff together and testing it. So many materials we thought we understood well have turned out to have completely new properties in the nano world. Similarly, materials under intense heat and pressure, such as the materials in the Earth's interior, are a complete unknown to us. We can't even simulate that much heat and pressure in our most powerful diamond anvils.

It's very exciting to witness the discoveries.
1 / 5 (1) Sep 14, 2012
Man! And I just tossed about 10lbs of that stuff that I'd had sitting around for years!

But seriously, whoever plans to use this technology had better make sure that those devices made with it are well isolated from static: just think of what one static jolt would do to all of those little 1s & 0s!
1 / 5 (1) Sep 14, 2012
What kind of speed are we talking about here?
Are we talking about being potentially able to make a 100 Ghz CPU for instance?

It'll be measured in peta-flops, the standard for super computers. Cray already makes some awesomely fast super computers.

But what I'm seeing is a laptop that would be able to keep pace with an entry level Cray. Imagine what an awesome gaming machine that would be...
not rated yet Sep 15, 2012
This is dead-in-the-water ... With optical systems at the horizon, it'd be foolish to invest the petabytes of bucks to establish this technology as the 'next step'. Not the chance of a snowball surviving in he..... oh you get the point..

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