Ternary semiconductors

Abstract

The group of the ternary compounds, which includes the chalcopyrite and many other less well known ordered and disordered semiconductors, has a number of physical properties, which are not found in the simpler binary semiconductors. For example, the chalcopyrites have not only direct and indirect band gaps but also pseudodirects energy gaps, which are formally direct but act physically like indirect gaps. Electronic and dynamic properties of these complicated compounds can be understood in a few simpler cases, when relationships are established to the very well understood elementary semiconductors. In the transformation diamond-zincblendechalcopyrite, for example, one atom of a sublattice is replaced at each step by two. In this manner the electronic and dynamical properties of chalcopyrite and related structures, like “Ordered Vacancy Compounds” are surveyed. Many, often even simple, properties of ternary semiconductors (eg. the structure) are on the other hand unknown or in dispute, so that a large number of theoretical and experimental problems are still waiting for their solution.