Deep impurities in semiconductors. I. Evanescent states and complex band structure

Abstract

The evaluations of the eigenstates and eigenvalues associated with deep impurities have been restricted to either very simple models or large computer calculations. The author presents an analytic method by which impurity properties may be calculated. It depends upon the calculation of the evanescent states, i.e. those non-Bloch states with energies in the band-gap, which match on to the impurity core to produce the complete state. It is shown that the band structure and the symmetry of the impurity determines the type of state required quite explicitly.