Enhanced terahertz ISBT in GaAsBi/AlGaAs quantum well: impact of doping modulation

One of the pivotal characteristics of quantum wells (QW) designed for applications in filters or modulators is its absorption coefficient. This study investigates the combined influence of doping and active layer thickness on the absorption coefficient in GaAsBi/AlGaAs quantum wells. The self-consistent coupling between Schrödinger and Poisson equations was employed for this purpose. A comprehensive analysis of conduction band structure, energy levels, potentials, and densities is presented. This analysis discerns the effects of doping on intersubband transitions (ISBTs) in the terahertz (THz) frequency domain. An introduction of a donor impurity into the system greatly influenced the intersubband absorption coefficient, increasing its intensity and causing the optical response to shift toward the lowest frequency. The obtained resonant peak energies, situated within the terahertz spectrum, hint at promising applications for GaAsBi-based devices within this frequency band.