A technique for fabricating Au/Ti micro- and nanotubes

For the first time, Au/Ti micro- and nanotubes were prepared by rolling initially planar, strained Au/Ti bifilms, freed from the Si substrates by wet selective etching of underlying Al sacrificial layers. Conducting metal tubes with diameters ranging from 20 mu m to 40 nm were made from 10 mu m wide and 10 cm long metal strips lithographically defined on Si substrates. Also, arrays of tubes rigidly attached to the substrate by unrolled parts of the film were obtained. Fully detached tubes could be bent to form sharp angles or loops without mechanical failure, due to their high plasticity. The shape and electric conductivity of the Au/Ti micro- and nanotubes were found to remain unchanged over a more than two-year long storage in ambient air.