Preparation and Characterization of Self-assembled Monolayers of Trichlorogermanyl Propanoic Acid and Its Derivatives

Self-assembled monolayers(SAMs) of trichlorogermanyl propanoic acid derivatives on hydroxylated silicon substrates are prepared for the first time. Contact angle measurement, ellipsometry and X-ray photoelectron spectrometry (XPS) are used to characterize these SAMs. It is demonstrated that a quasi-2D network is formed on the surface of the substrate after molecules adsorbed on it. The molecular chains have certain tilt angles to the substrate surface. The wettabilities of the SAMs are various, because the molecules adsorbed and liquids used in the experiments are different. It can be concluded that trichlorogermanes have similar self-assembly behavior as trichlorosilanes. Four SAMs are studied together: they are acid, ethyl, butyl and hexyl surfaces whose results are of good consistency.