Conduction-band tailing in parabolic band semiconductors

Kane's [Phys. Rev. 131, 79 (1963)] model for the density of states for energies in the band gap is in qualitative agreement with experiment. Halperin and Lax [Phys. Rev. 148, 722 (1966)] have also suggested a model for band tailing, which is applicable to the deep tailing states. In the present study, theoretical models have been proposed for the band tailing in the case of heavily doped semiconductors that are more general than those of Kane and others. In addition, the present study also offers an E-(k) over bar dispersion relation for band tails in the parabolic band based on Kane's semiclassical theory. This study has helped us to obtain a different model for the density of states in the band-tailing conditions and the model is expected to agree better with experiment. (C) 1997 American Institute of Physics.