Intra-miniband absorption coefficient in GaAs/AlxGa1−xAs core/shell spherical quantum dot

Abstract

In this work we reported the theoretical calculations of the absorption coefficient in a GaAs/AlxGa1−xAs core/shell spherical quantum dot as a function of the aluminium concentration x in the direct band-gap regime, and core and shell size (inner radius r1, and the external one r2). The effective mass approximation and the hybrid matrix method were used to calculate the electronic structure of the system. The considered optical absorption transition is between the 1s and 1p electronic states. We found that the computed absorption coefficient experiences a red- and blue-shift as the considered parameters change. The intra-miniband formation is generated by means of the overlap of the absorption coefficient considered in a distribution of the GaAs/AlxGa1−xAs core/shell spherical quantum dots with different core and shell sizes. Based on the obtained results, we proposed that the better way to form an intra-miniband is to consider a GaAs/AlxGa1−xAs core/shell spherical quantum dot with different values on the inner radius instead of increase the external radius value.