Nanowires go catalyst-free Nanofabrication

Nanofabrication

June 25, 2008

Randomness inherent in the synthesis of metal nanowires has prevented these structures from being incorporated into high-density electronic and optoelectronic devices. Researchers from the University of Illinois at Urbana-Champaign have now demonstrated how a low-temperature, catalyst-free technique can produce copper nanowires that could be suitable for display applications [Kim et al., Adv. Mater. (2008) 20, 1859].

Changwook Kim and colleagues use chemical vapor deposition with a Cu(ethyl-3-oxobutanoate)[triethyl phosphate]2 precursor to grow Cu nanowires on a variety of surfaces. The diameters and lengths of the nanowires are controlled by altering the substrate material, the temperature, deposition time and precursor feeding rate.

Structural analysis reveals the Cu nanowires have a fivefold twinned structure, terminating in a sharp, pentagonal tip and current-voltage investigations indicate that they are also promising electron emitters.

An array of Cu nanowires was grown on a patterned Si substrate to test the potential of this growth process in a practical application. Electrons emitted from the nanowire tips were used to activate the letters ‘UI’ on a phosphor-coated glass anode. “Packing a large number of emitters into a patterned area may be an attractive option for electron emitters that may help achieve a long-lasting field emission display,” the authors wrote.

The catalyst-free synthetic procedure is compatible with contemporary silicon-processing protocols, adds coauthor Hyungsoo Choi. The low processing temperature makes this method suitable for the use of metal nanowires in plastic electronic displays.

Paula Gould