Self-catalytic and selective growth of ZnO nanoneedles by micro-contact printing and CVD.

A self-catalytic method to selectively grow ZnO nanoneedles is demonstrated by simply combining a conventional micro-contact printing (mu-CP) and two-step metal-organic chemical vapor deposition (MOCVD) techniques. Self-assembled monolayers (SAMs) of octadecyltrichlorosilane (OTS) were patterned on Si substrates by mu-CP. The patterned structures of the ZnO nanoneedles were realized on the SAMs-patterned Si substrates by two-step MOCVD at high temperature of 600 degrees C via the initial preparation of a thin ZnO seed layer with retaining the patterned morphology at low temperature of 170 degrees C. This combined method of mu-CP and self-catalytic two-step MOCVD should be applicable to fabricate the patterned alignments of metal oxide nanostructures.