Ordered arrays of epitaxial silicon nanowires produced by nanosphere lithography and chemical vapor deposition

Gold dot arrays on (1 1 1) Si substrates obtained through nanosphere lithography (NSL) combined with sputtering and annealing in Ar at 1000 degrees C are used to catalyze vapor liquid solid (VLS) epitaxial growth of silicon nanowires (Si NWs) using chemical vapor deposition (CVD) with SiH(4) in Ar. The NWs grow primarily epitaxially on the underlying (1 1 1) Si wafer following the four independent < 1 1 1 > directions. The diameter distribution of the wires reflects the diameter distribution of the catalyst gold dot arrays and is therefore predictable. The wire length depends on the size of the gold catalyst for the same CVD parameters. The wire position is foreseeable within the limits of the pattern geometrical quality, but one-to-one growth of NWs to gold dots is not always observed, probably due to (very locally) the remaining presence of silicon oxide. Overall, this inexpensive patterning method for obtaining high-quality crystalline VLS Si NWs by CVD fulfills the requirements of many device applications, where patterning control, quality and reproducibility of the nanostructures are crucial. (C) 2010 Elsevier B.V. All rights reserved