Theory of Impurity States in Superlattice Semiconductors

Abstract

This paper presents a review of the theory of impurity states in superlattice semiconductors. First of all, a brief description is given of the effective-mass theory for shallow impurities in bulk semiconductors. A modification of the method is described to deal with hydrogenic donor states in a quantum well. A further modification of the method is described which allows for donor level calculations in a superlattice or a multiple quantum well. For calculating acceptor levels in quantum wells a multiband effective-mass theory is described. Finally, a self-consistent method, within the local-density and effective-mass approximations, is described for calculating electronic subband structure in the n-type layers of a n-i-p-i crystal.KeywordsSuperlatticessuperlattice semiconductorssemiconductorsimpurity statesimpurities in semiconductorstheory of impurity stateseffective mass theorynipi crystalsimpurity states in superlattices