Analysis of AlGaAs/GaAs/InGaAs n-type step multiple quantum wells for the optimization of normal incident absorption

摘要

The response to normal incident radiation in n-type Γ square quantum wells (QWs) is generally expected to be very small because, in the framework of the effective mass model, the parity selection rule of the envelope wavefunctions essentially forbids intersubband transitions induced by transverse electric polarized radiation. This problem can be overcome by employing an asymmetrical QW. In this paper, the effect of asymmetry, and the result of band mixing with the p-like valence and conduction bands due to the truncation of bulk crystal periodicity, of an n-type AlGaAs/GaAs/InGaAs step multiple QW, are analysed using a new 14-band k·p model with envelope function approximation.