Thermal instability of copper nanowires

Copper nanowires have been fabricated by electrochemical deposition into hollows, which are formed by selective etching of swift heavy ion tracks in thin foils. After removal of the matrix. the free copper nanowires are heated to about 500 °C, whre they decay into chains of nanodots. It is proven that the nanowires decay well below the melting temperature of copper is due to the Rayleigh instability. Copper nanowires fabricated in polycarbonate foils are covered by polymer rests after matrix removal. We call them metal wires within Carbon NanoTubes (CNT). In situ annealing in a transmission electron microscope (TEM) reveals an interesting evolution of these nanostructures: Surface minimization leads to a copper droplet formation at one of the openinigs of the CNT. The emtying of the CNT accelerates with the inverse droplet volume. Modeling results in an analytical description as well as in atomistic computer simulations, which are in excellent agreement with the experiment. This well-defined process could be used to measure materials parameters at the nanoscale.