Functionalization of Semiconductor Surfaces

CHAPTER 5

Chemical Binding of Five-Membered and Six-Membered Aromatic Molecules

FRANKLIN (FENG) TAO AND STEVEN L. BERNASEK

5.1 INTRODUCTION

Understanding the mechanism of reaction of five- and six-membered aromatic organics with semiconductor surfaces at the atomic level provides the foundation for further chemical attachment of multilayer organic materials to these semiconductor surfaces. These chemical reactions and related biofunctionalization of semiconductor surfaces is important for the development of sensing technology. This chapter focuses on the reaction mechanism of these representative categories of organic molecules. It is organized by starting from simple five-membered ring molecules, benzene, six-membered aromatic molecules with one heteroatom, and ending at six-membered aromatic molecules with two heteroatoms. For each category of these molecules, their reaction mechanisms on different semiconductor surfaces are reviewed and compared in order to understand the electronic and structural factors that affect the chemical functionalization.

5.2 FIVE-MEMBERED AROMATIC MOLECULES CONTAINING ONE HETEROATOM

Thiophene, furan, and pyrrole are three representative five-membered ring aromatic molecules with one heteroatom, as shown in Fig. 5.1. Their chemical binding on Si(111)-(7×7), Si(100), and Ge(100) have been extensively studied. Each of the three molecules exhibits different reaction mechanisms in the modification and functionalization of semiconductor surfaces due to ...