Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Interfaces
Abstract This chapter deals with the electronic properties of interfaces, i.e. the abrupt transition from one bulk material to the other one. There has been substantial progress in recent years in the growth of well-defined and reproducible interfaces. One is also beginning to obtain reliable experimental values for the band discontinuities, e.g. Schottky barrier heights, heterojunction band offsets, etc. These values now represent severe tests of the predictive value of the different theories. In this regard the first theoretical models concerning the interface between two materials have always attemped to relate the interface discontinuity to the properties of the material-vacuum interface, i.e. essentially the work function for a metal and the electron affinity for a semiconductor. Such treatments neglect interface dipoles and take the vacuum level as reference. For reasons discussed in the following these treatments usually fail. However, other simple models have been devised based on the use of a neutrality level whose common denominator is shown to be that dangling bond states are involved. The dangling bond states allow one to understand why the Schottky barrier height, the heterojunction band offsets and the transition impurity levels are all correlated. This point of view is confirmed by recent quantitative calculations and the degree of accuracy now obtained for the prediction of band discontinuities is of the order of 0.1 eV. Finally we discuss the Si-SiO2 interface where again dangling bonds play an important role but this time as interface defects.
Interfaces
Abstract This chapter deals with the electronic properties of interfaces, i.e. the abrupt transition from one bulk material to the other one. There has been substantial progress in recent years in the growth of well-defined and reproducible interfaces. One is also beginning to obtain reliable experimental values for the band discontinuities, e.g. Schottky barrier heights, heterojunction band offsets, etc. These values now represent severe tests of the predictive value of the different theories. In this regard the first theoretical models concerning the interface between two materials have always attemped to relate the interface discontinuity to the properties of the material-vacuum interface, i.e. essentially the work function for a metal and the electron affinity for a semiconductor. Such treatments neglect interface dipoles and take the vacuum level as reference. For reasons discussed in the following these treatments usually fail. However, other simple models have been devised based on the use of a neutrality level whose common denominator is shown to be that dangling bond states are involved. The dangling bond states allow one to understand why the Schottky barrier height, the heterojunction band offsets and the transition impurity levels are all correlated. This point of view is confirmed by recent quantitative calculations and the degree of accuracy now obtained for the prediction of band discontinuities is of the order of 0.1 eV. Finally we discuss the Si-SiO2 interface where again dangling bonds play an important role but this time as interface defects.
Interfaces
Dr. Lannoo, Michel (Autor:in) / Dr. Friedel, Paul (Autor:in)
01.01.1991
43 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
| TIBKAT | 2020
| British Library Conference Proceedings | 2003
| Springer Verlag | 2004