“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 Advanced Functional Materials. 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 electrical properties 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.”

Image: Nanowires crafted from vanadium oxide and lead. These wires‘ unique electrical properties could make them ideal for use in switching components of computers. © Peter Marley, with colored added

http://www.buffalo.edu/news/13667

Peter M. Marley, Adam A. Stabile, Chun Pui Kwan, Sujay Singh, Peihong Zhang, G. Sambandamurthy, Sarbajit Banerjee: Charge Disproportionation and Voltage-Induced Metal-Insulator Transitions Evidenced in β-PbxV2O5 Nanowires, In: Advanced Functional Materials, Early View, August 17, 2012, DOI:10.1002/adfm.201201513: http://dx.doi.org/10.1002/adfm.201201513