EFFECTIVE-MASS SUPERLATTICE - DENSITY-OF-STATES STUDIES

Density-of-states (DOS) investigations of a finite effective-mass supe rlattice (EMSL) are reported for the first time. For a perfectly perio dic EMSL, the dependence of DOS distributions on the number of periods is discussed and the development of the energetic mini-band structure is shown. For EMSL perturbed at the internal surface (i.e. the substr ate/EMSL interface) by a potential step, an effective-mass 'jump ' or a modified width of the outermost EMSL layer, features in DOS spectra appear inside energetic mini-gaps and they are found to correspond to the states localized at the internal surface of EMSL.