Controlled Deposition of Gold Nanoparticles on Well-Defined Organic Mono layer Grafted on Silicon Surfaces

The use of nanoparticles for advanced applications critically depends on the control of the interfaces between the substrate, the intermediate/linking layer, and the nanostructures. While much work has been done to attach nanoparticles and to determine their properties, less effort has been devoted to the quality of starting surfaces and little is known about the impact of the attachment process on the pre-existing interfaces. In this study, the properties of interfaces of two model surfaces obtained by covalently grafting alkyl chains directly to oxide-free silicon surfaces, either via Si 0 C or Si C bonds are compared with those currently obtained by attaching organic silane molecules (e.g., (aminopropyl)triethoxysilane) on oxidized silicon surfaces. Using FTIR, Raman spectroscopy, atomic force microscopy, and spectroscopic ellipsometry, we show that nanopatterned Si-O-C surfaces suffer some oxidation upon attaching nanoparticles, although they remain stable in ambient environments. In contrast, surfaces with Si-C bonds remain oxide free and remarkably stable during and after gold nanoparticle attachment. The attachment of AuNP to these oxide-free, stable semiconductor surfaces opens the way to applications sensitive to interface state quality.