Mechanochemical method to prepare aryl diazonium salts monolayer on silicon surfaces

A micromachining system based on diamond tool is built, which can process micro structure in solution. The system is used to scribe the silicon surface in aryldiazonium salt solution (NO₂ C₆H₄N₂BF₄). Arenes can be connected with silicon atom with covalent bonds. Functionalizing and patterning silicon surface are realized simultaneously. This approach will be employed to build nano-scale functional structures. To obtain microstructures with better quality which will act as a good substrate for the following functionalizing and patterning processes, scanning electron microscopy (SEM) is used to characterize the surface morphology with different cutting force. X-ray photoelectron spectroscopy (XPS) as well as atomic force microscopy (AFM) are used to verify the self-assembly monolayers. Effects of the scribed speed and assembly time on the quality of self-assembled monolayer (SAMs) are discussed, which results in suitable testing parameters (20 mN cutting force, 12 h assembly time and 500 nm/s scribing speed) to produce better films. Atomic force microscopy (AFM) is used to characterize the surface frictional performance. The chemical composition of silicon surface changes after self-assembly, and the friction force of SAMs surface becomes greater.