Chapter 3 - Self-Assembled Monolayer on Silicon

Abstract

This chapter discusses self―assembled monolayer on silicon. The chapter explains self―assembling, in which minute elements such as atoms, molecules, and clusters are spontaneously organized into an ordered array of the elements, is a key process of the bottom–up nanotechnology. The promising material processes on the basis of self-assembly are the fabrication of organic thin films with a monomolecular thickness. Self-assembled monolayers (SAMs) are those organic molecules that adsorb on a particular substrate and form a monolayer. Most of the SAM precursors have a long alkyl chain or an aromatic ring so that some types of intermolecular interactions work among the chemisorbed molecules. Once a SAM is formed on a substrate, its surface is entirely covered with organic molecules. The thickness of the SAM is determined with the length of the precursor molecules and an adsorption angle of the molecules. The formation of SAMs depends on unique chemical reactions between a substrate and organic molecules. Hence, specific pairs of a substrate and a precursor are required to fabricate SAMs. Furthermore, micro- and nanopatterning of the SAMs on Si, based on VUV-light irradiation and current-injecting AFM, respectively, has been described in the chapter. The chapter concludes by enlisting some of the electric properties of the SAMs––that is, surface potential, contact resistance, and redox activity.