Figure 1

Schematic illustration of the nanowire array production steps. a Top view of an electrochemically etched regular macropore array. The dashed circles indicate the effect of the chemical over-etching, which eventually yields the (black) nanowires shown in (b) (top view). c The bulk Si has to be insulated from the Li by a Cu diffusion barrier layer to avoid the incorporation of Li into the bulk Si. The Cu layer also serves as electrical contact to the Si nanowires