Growth of vertically aligned Si wire arrays over large areas (>1 cm2) with Au and Cu catalysts

Arrays of vertically oriented Si wires with diameters of 1.5 mu m and lengths of up to 75 mu m were grown over areas > 1 cm(2) by photolithographically patterning an oxide buffer layer, followed by vapor-liquid-solid growth with either Au or Cu as the growth catalyst. The pattern fidelity depended critically on the presence of the oxide layer, which prevented migration of the catalyst on the surface during annealing and in the early stages of wire growth. These arrays can be used as the absorber material in novel photovoltaic architectures and potentially in photonic crystals in which large areas are needed.