Hexagonal nanoholes, in which an array of Au nanoparticles was located, were successfully fabricated on the basis of scanning probe anodization lithography. The lithography has been conducted to draw nanopatterns on a hexadecyl self-assembled monolayer covalently bonded to a Si substrate through Si-C bonds. Using a conductive atomic force microscope (AFM) probe as a point contact electrode, current was locally injected into the monolayer-Si sample. The monolayer was decomposed on the location where current injected. Subsequently, at this point, the substrate Si was anodized resulting in the formation of an oxide nanodot. Next, the oxide nanodot was selectively etched with HF in order to make a nanohole while the surrounding monolayer remaining unetched. As a result, a nanohole was formed at the current injected point. Employing the remained monolayer as an etch mask, the nanohole was further etched with NH4F in order to prepare a well-defined hydrogen-terminated surface in the nanohole. The nanohole became hexagonal due to the anisotropic nature of Si etching with NH4F. The lateral size of the fabricated nanohexagonal holes were in the range of 180 similar to 320 nm. Finally, electroless plating was applied to the sample. Au nanoparticles were selectively nucleated on the surface of the nanohole's bottom and walls. The particles with a diameter less than 10 nm were well-separated each other with a nucleation density of 150,000 mu m(-2). The NH4F etching was successful in order to control the nucleation manner for the fabrication of the Au nanoparticle array.
