Electronic States and transmission in GaAs/GaAlAs multi-quantum wells with geometrical defects

Abstract

In this paper, we use the Green’s function approach to conduct the theoretical study of the propagation of electron waves in a multi-quantum wells (MQWs) made up of GaAs and GaAlAs layers with a periodic structure. Localized electronic states are produced inside the band gaps due to the presence of defects of various types inside the MQWs. These states are extremely sensitive to the thicknesses and the position of the different inserted defect layers. The transmission rate of these states is always at its highest as the number of defects rises. Similar to this, we found that the transmission rates of these defect layers decrease the further apart they are. Thus, when the defect position is separated by more than two cells, this kind of interaction is stronger; however, when they are brought closer, it is weaker. Due to the energy transfer between the various electronic states created inside the band gaps, the origin of the states induced by the wells defect becomes a state induced by the barrier defect, and vice versa. This causes a change on the behavior of the induced electronic localized states.