Interface States

Abstract

The physically most interesting aspect of semiconductor interfaces is the lineup of the energy bands of the two materials in contact. In a metal-semiconductor contact, the characteristic quantity is the barrier height, which measures the energy distance between the Fermi level and the edge of the respective majority-carrier band of the semiconductor at the interface, while the discontinuities of the valence- and the conduction-band edges are the relevant parameters for semiconductor heterostructures and semiconductor-insulator interfaces. The electronic properties of the different types of semiconductor interfaces may be explained by one conceptually simple approach. This concept is again based on the virtual gap states of the complex band structure of semiconductors as well as insulators. This model assumes intimate contacts which are abrupt and free of any defects and impurities.