Adv. Func. Mater.http://dx.doi.org/10.1002/adfm.201102665 (2012)

Shining green laser light onto nanostructured gold or silver films coated with amorphous carbon can induce a phase transformation that makes the carbon highly conductive, according to researchers from the Georgia Institute of Technology in the USA. The nanostructures exhibit a plasmonic resonance that strongly absorbs 514 nm laser light, causing intense localized heating of the carbon and a resulting phase change into a nanocrystalline or disordered graphitic phase, as confirmed by Raman spectroscopy and atomic force microscopy. Conductive force microscopy suggests that the changed state offers an electrical resistivity that is at least seven orders of magnitude lower than the initial insulating surface or unexposed regions. In contrast, tests with a reference silicon substrate showed no changes in morphology or conductivity, which indicates the importance of the metal nanostructures for the phase change. The researchers suggest that the technique might be useful for fabricating complex patterns of metal–carbon electrical interconnects.