The conduction band in non-crystalline semiconductors

Abstract

Following investigations by P. Thomas and co-workers, the energy of the current path in the conduction band of non-crystalline semiconductors and its relation to the calculated mobility edge is investigated. Delocalization is assumed to occur when L _i < ζ, where ζ is the localization length and L _i the inelastic diffusion length. For a non-degenerate gas we believe that localization is never complete, in contrast to the situation in metals. Both amorphous silicon and impurity bands in crystalline materials are discussed. The relationship of the pre-exponential factor in the conductivity to the predictions of scaling theory is investigated. No evidence is found for any error in the latter.