Terahertz intersubband transitions in GaAsBi/AlGaAs single quantum well heterostructure

Abstract

Abstract GaAsBi/AlGaAs single quantum well conduction band structure, energy levels, and their corresponding wavefunctions have been calculated by solving the Schrodinger equation. The influences of the heterostructure parameters on the intersubband transition (ISBT) frequency within the terahertz (THz) domain have been investigated. The results show that the quantum well width has a great impact on the THz ISBT frequency. In particular, an ISBT with a frequency of 2.611 THz (10.80 meV) has been obtained for specifically optimized parameters. The study of the intersubband optical absorption coefficient (OAC) was centered in the frequency band of 2–14 THz (~8–58 meV), therefore the corresponding results are useful for the optimization of THz detectors. Correspondingly, by changing the thickness of the active layer the number of the OAC peaks has been tuned. The dipole matrix element and the Fermi occupation function have been also studied in detail. Furthermore, the influences coming from the incidence angle on the OAC intensity were numerically investigated. The obtained results could be beneficial for the design and the optimization of devices operating in the THz frequency band.