ABSTRACT
This chapter discusses the fundamental properties of semiconductor materials and reviews different theoretical methods that provide insight into the electronic structure of these systems to understand and predict their properties. It focuses on the consequences of the fact that solid-state materials are crystalline with a periodic lattice. The chapter provides the electronic band structure of semiconductor materials and their specific features are of central importance for determining their electronic and optical properties. It presents a detailed overview of different, widely used methods to describe the electronic band structure of semiconductor materials and focuses on the consequences of the fact that solid-state materials are crystalline with a periodic lattice. Since the inner electronic shells are only slightly affected by the field of all the other atoms, for the description of the bulk band structure it is sufficient to take into account the states of the outer shells.
