Large-area and uniform amorphous metallic nanowire arrays prepared by die nanoimprinting

Metallic glasses (MGs) possess not only superior mechanical and functional properties but also excellent net-shape forming ability, which could be used for fabricating nanostructures and nanodevices. In order to overcome the drawback of the commonly used free nanoimprinting technique, where the stress decreases along the radial direction of the nanoimprinting surface, a die nanoimprinting technique has been developed, which can effectively enhance the stress uniformity within the supercooled liquid of the glassy alloys. By employing the developed die nanoimprinting technique, large-area Pd40.5Ni40.5P19 amorphous metallic nanowire arrays (MNWAs) with nanowire (NW) diameters of about 55 nm and uniform length around 650 nm have been prepared. It has been found that the structure and the geometry of the NWs are highly sensitive to the nanoimprinting parameters. The nanocrystals, observed on the surface of the front end of the partially crystallized NW, were confirmed to be mainly resulted by the thermal effect. Reducing processing temperature, processing time and enhancing the applied pressure could suppress crystallization and fabricate NWs with full amorphous structures. The present result indicates that die nanoimprinting is an effective approach for fabricating large-area uniform MNWAs or other nanodevices with full amorphous structure through adjusting the processing parameters. (C) 2014 Elsevier B.V. All rights reserved.