Electrical properties of end-group functionalised Self-Assembled Monolayers

Abstract

In a previous study we have demonstrated that a single monolayer of alkyl-trichlorosilane molecules, covalently bonded to the native oxide of a silicon substrate, allows the fabrication of MIS (Metal-Insulator-Semiconductor) devices with excellent electrical properties [C.Boulas et Al., Phys. Rev. Lett. 76, 4797(1996)]. Here we demonstrate that we can functionalise the end-groups of the molecules, once grafted to the substrate, without disturbing the excellent insulating properties of the monolayer. The functionalisation of the monolayer is monitored by FTIR and ellipsometry. Conductivity, photoconductivity and capacitance measurements are performed to study the effect of the chemical functionalisation on the electrical properties of the monolayer. Finally, possible sub-0.1 μm device applications are presented.