Tsukuba, Japan--Scientists at the National Institute for Materials Science (NIMS) have selectively grown polymer nanowires using only irradiation with a pulsed laser, in a region limited to the area of irradiation. They have also succeeded in doping the nanowires with various species of nanomaterials.
Polymer nanowires are extremely flexible and optically transparent, and could have wide application in nanodevices such as sensors, light-emitting devices, optical switches, and others. However, there have been two problems. One was the need to substantially reduce the size of the nanowire, and the other was that lack of ability to add various dopants to impart new functions. In the present work, the NIMS researchers described a simple method using only a pulsed laser—an approach very different from the conventional fabrication method—and simultaneously solved the two persistent problems.
Nanodevices have attracted attention because new functions can be obtained by utilizing the so-called quantum-size effect. To obtain this effect, it is necessary to reduce the diameter of nanowires down to several 10 nm or less. Molds are used in the conventional nanowire fabrication technique, but fabrication by this method had been limited to comparatively thick wires with diameters of several hundreds of nanometers. Furthermore, with the conventional technique, polymer nanowires were extracted from the mold by etching away the mold with a strong chemical agent, and it was only possible to use polymers that would not be damaged by the chemical.
In the new research, the NIMS team (at the Nano Electronic Materials Unit) irradiated a highly-controlled laser on the material without using a mold, causing a nanowire to form at the position of irradiation as though growing. Various dopants could be added to the starting material.
Practical application of the resulting polymer materials is expected in fields such as wiring for flexible substrates of smart phones, where increasingly active development is anticipated, and in flexible high-magnetic-permeability materials in antennas for portable electronic devices, where miniaturization is required.
Source: http://www.researchsea.com/
