Theoretical calculations of absorption spectra of GaNAsBi-based MQWs operating at 1.55 μm

By applying the band anticrossing model combined with the envelope function formalism, a theoretical study of optoelectronic properties of lattice matched GaNAsBi-based multiple quantum wells (MQWs) operating at 1.55 μm was performed. Indeed, the electronic band structure of 4.5 nm GaN_.04As_.89Bi_.07/GaAs double quantum wells (DQWs) was computed for a barrier width (L_b) varying from 1 to 12 nm. We found that the coupling between GaNAsBi wells which occurs for L_b ≤ 8 nm, modifies the confined energies levels and the fundamental interband transition of the coupled GaNAsBi/GaAs DQWs. This produces a slight shift of the wavelength emission from 1.55 μm. We have also discussed the coupling effect on the in-plane carrier effective mass and the optical absorption spectra of these DQWs. Basing on the enhancement of electron mobility and the slight amelioration of absorption peak magnitude brought by the well coupling, we have chosen the GaN_.04As_.89Bi_.07/GaAs DQWs with L_b = 3.5 nm and L_w modified to 4.3 nm as a candidate for optoelectronic devices operating exactly at 1.55 μm. Finally, we are focused on the investigation of the optical properties of 7(GaAs)_3.56(GaN_.04As_.89Bi_.07)_4.1 superlattices (SLs) operating at 1.55 μm especially the absorption coefficient behavior. - Highlights: • Band anticrossing model and envelope function formalism were used in this study. • Coupling between GaNAsBi wells improves the electron mobility of the studied DQWs. • For 4.5 nm GaN_.04As_.89Bi_.07/GaAs DQWs, the coupling effect occurs for L_b ≤ 7 nm. • Optical absorption spectra of GaN_.04As_.89Bi_.07/GaAs DQWs were calculated. • 7(GaAs)_3.5 6(GaN_.04As_.89Bi_.07)_4.1 SLs can operate at 1.55 μm at room temperature