Adsorption of Multifunctional Organic Molecules at a Surface: First Step in Molecular Layer Deposition

Abstract

Adsorption of organic molecules onto inorganic surfaces can be used as a first step toward creating hybrid interfaces for new applications. Molecules with multiple functionalities have the possibility of binding to the surface through one functional group while leaving unreacted other groups that can change the surface chemistry and its properties. This article focuses on the driving forces that are present during multifunctional molecule adsorption on surfaces of semiconductors such as silicon and germanium. We show that adsorption of multifunctional molecules can be influenced by three different effects: (i) geometric effects due to backbone structure, bond strain, and the distance between reactive sites; (ii) electronic effects within a molecule or between adsorbate molecules; and (iii) competition between heteroatoms. In cases where the adsorption of organic molecules is driven by molecule–molecule or molecule–surface interactions, these effects can be modulated as a function of surface coverage. A primary goal is to understand when these effects are expected to be present and how they can be used to achieve selective adsorption.