LACK OF BAND-OFFSET TRANSITIVITY FOR SEMICONDUCTOR HETEROJUNCTIONS WITH POLAR ORIENTATION - ZNSE-GE(001), GE-GAAS(001), AND ZNSE-GAAS(001)

The fabrication of pseudomorphic Ge layers in the interface region of ZnSe-GaAs heterostructures was recently shown to be an effective metho d of reducing the overall valence-band discontinuity. We investigate h ere the microscopic mechanism behind this effect, drawing on measureme nts and theoretical calculations of the band offsets for individual is olated heterojunctions between the different semiconductor constituent s. We find that the formation of different interface configurations in individual neutral heterojunctions can account for the observed devia tions from the predictions of the transitivity rule and hence for the effect of Ge interlayers.