Electronic Structure of Semiconductor Interfaces

This concise volume examines the characteristic electronic parameters of semiconductor interfaces, namely the barrier heights of metal–semiconductor or Schottky contacts and the valence-band discontinuities of semiconductor–semiconductor interfaces or heterostructures. Both are determined by the same concept, namely the wave-function tails of electron states overlapping a semiconductor band gap directly at the interface. These interface-induced gap states (IFIGS) result from the complex band structure of the corresponding semiconductor. The IFIGS are characterized by two parameters, namely by their branch point, at which their charge character changes from predominantly valence-band- to conduction-band-like, and secondly by the proportionality factor or slope parameter of the corresponding electric-dipole term, which varies in proportion to the difference in the electronegativities of the two solids forming the interface. This IFIGS-and-electronegativity concept consistently and quantitatively explains the experimentally observed barrier heights of Schottky contacts as well as the valence-band offsets of heterostructures. Insulators are treated as wide band-gap semiconductors.

Introduction.- Experimental Data Base.- From the Schottky-Mott Rule to Interface-Induced Gap States.- Interface-Induced Gap States.- Comparison of Theoretical and Experimental Data.- Irradiation- or Defect-Induced Gap States.- Conclusions.

Winfried Mönch received a Dr.rer.nat. degree from the Georg-August-University of Göttingen in 1961. He spent three years in the Semiconductor Department of the AEG Research Institute Frankfurt-Main before moving to the RWTH Aachen University. There he was awarded the venia legendi for physics in 1968 and became an Associate Professor two years later. In 1974 he was appointed Professor at the University of Duisburg (since 2003 University of Duisburg-Essen) and retired in 1999. He was the first Walter Schottky Visiting Professor at Stanford University in 1981 and received the E.W. Müller Award 1984 from the University of Wisconsin-Milwaukee. He has authored two monographs on semiconductor surfaces and interfaces, which have been published in the Springer Series in Surface Sciences.