Slicing Nanowires Into Nanocrystal Arrays

Researchers have sliced silver nanowires to make precise linear arrays of crystalline nanoparticles (J. Phys. Chem. Lett. 2013, DOI: 10.1021/jz400716j). Such arrays could form the basis of optical circuitry used in high-speed communications and quantum computers.

Aligned nanocrystals can trap light on their surfaces as particles called plasmons. These plasmons help transmit light from one end of an array of nanoparticles to another, says Alison M. Funston of Monash University in Australia. By guiding light as plasmons through these arrays, researchers think they can focus light signals into nanosized spaces without the light diffracting and losing information.

Unfortunately, it is difficult to precisely place crystalline nanoparticles in an array with controlled spacing and crystal size. Past efforts using lithography produced particles with ill-defined crystal structures and rough surfaces, making them inefficient at transporting light.

The Australian team tried another approach. They first synthesized crystalline silver nanowires and placed them on a glass slide. The scientists then cut the wire into separate nanoparticles using a focused ion beam. Because the nanowires are highly crystalline and have smooth surfaces, so do the resulting particles.

The researchers made arrays of more than 50 nanocrystals. The team now is testing how efficiently the arrays guide light.