Researchers question reliability of carbon nanotubes

The researchers fabricated and tested numerous nanotube interconnects between metal electrodes and found that they could sustain extremely high current densities for several hours, but that they slowly degraded under constant current. Of greater concern, they said, was the fact that the metal electrodes failed when currents rose above a certain threshold. In another related study, the researchers identified failures in carbon nanotube networks - materials in which electrons physically hop from tube to tube. Failures in this case occurred between nanotubes, the point of highest resistance. By monitoring the starting resistance and initial stages of material degradation, the researchers could predict whether resistance would degrade gradually - allowing operational limits to be set - or in a sporadic, unpredictable way that would undermine device performance. Despite the reliability concerns, however, NIST postdoctoral researcher, Mark Strus believes carbon nanotube networks could still be very useful in some electronic applications. "Carbon nanotube networks may not be the replacement for copper in logic or memory devices, but they may turn out to be interconnects for flexible electronic displays or photovoltaics," he said.