Localized defect states based on defective multi-quantum wells

Abstract

The aim of this paper is to present a theoretical study of the transmission coefficient for a periodic CdMnTe/CdTe system containing a geometric and material defect layer. The dynamic tuning of this defect layer is investigated using the transfer matrix for the theoretical calculations. It is shown that the thickness and the concentration of the defect layer have a strong impact on the electronic states (called also defect modes) localized in the band gaps. Moreover, the transmission coefficients of these defect states reach maximal values when the defect layer is placed in the middle of the structure; this is due to the constructive interferences caused by the symmetry of the system. Further, the defect states shift to lower energies with the increase of the concentration or the thickness of the defect layer as well as the decrease of the quality factor. These findings are useful to design a nano-energy filtering and sensoring devices.