Controlled free-form fabrication of nanowires by dielectrophoretic dispension of colloids

The vertical growth of conductive gold nanowires in ambient atmosphere through on-demand dielectrophoretically guided deposition of nanoparticle-laden colloids is demonstrated. Accelerated by dielectrophoresis, rapidly evaporating colloidal droplets leave a capillary nozzle (diameter of 500 nm) and are guided through an inhomogeneous electrostatic field. The nanoparticles in the colloidal droplets combine under the action of van der Waals attraction forces on the substrate to form highly flexible vertical nanowires with easily controllable lengths and diameters, here in the range of 150-800 nm. After bending to bridge an electrode pair and after annealing at 300 degrees C, the sample gold nanowires demonstrate excellent electrical conductivity considering their size.