Nanopatterned assembling of colloidal gold nanoparticles on silicon

A quasi-one-dimensional (quasi-1D) Au nanocolloids array has been fabricated on silicon by combining the techniques of atomic force microscopy (AFM)-based nanooxidation and chemical assembling of colloidal nanoparticles. The silicon substrate, modified with an octadecyltrichlorosilane (OTS) monolayer, was first subjected to a localized chemical oxidation by using conductive AFM to form silicon oxide lines. After further modification of the oxidized region with an aminopropyltriethoxylsilane (APTES) monolayer via selective chemical adsorption, the substrate was exposed to a colloidal suspension of gold for deposition of gold nanoparticles, It is found that the Au nanoparticles can be selectively immobilized onto the AFM tip-defined amino-terminating regions of the silicon surface, forming quasi-1D gold nanoparticle arrays. The patterned structure is highly controllable and reproducible, which, we believe, will contribute to studies of nanodevices and mesoscopic phenomena.