Controllable metal nanodots array fabricatied by SDS-assisted nanosphere lithography and its application for nanowires growth

Periodic metal nanodots arrays with controllable size and spacing were prepared by nanosphere lithography (NSL). The polystyrene nanospheres (PNs) arranged on Si substrate by spin coating were used as a template for metal sputtering. Sodium dodecyl sulfat (SDS) was added as an activator in PNs solution to improve the interaction between PNs. The effects of the spin coating speed and the concentration of SDS on PNs arrangement were investigated separately. By changing above two spin coating conditions, the centrifugal force (F_cent) and capillary force (F_cap) acting on PNs during spin coating can be adjusted, thereby obtaining uniform PNs monolayer template. The center spacings between nanodots of both Au and Pt nanodot arrays matched well with the PNs (300 nm and 500 nm) templates. And the periodicity and uniformity of nanodots prepared by NLS are better than those directly annealed without templates, this indicated that using PNs templates as mask is a feasible and effective method for fabricating controllable periodic metal nanodots. As an extended application, Au nanodots arrays prepared were first used for the growth of GaN nanowires (NWs) by chemical vapor deposition (CVD) method. The diameter of NWs was consistent with the size of Au catalyst nanodots, whose size can be controlled by adjusting the PNs template. It provides a new technology of catalyst preparation for the controlble growth (diameter, density, and position) of NWs.