Investigation of the doping and Stark effects on the band structure and optical absorption of 1.55 μm GaNAsBi/GaAs MQWs

• Doping effect on band structure of 1.55 μm GaNAsBi/GaAs MQWs is studied.
• A red shift of the fundamental transition is shown due to the coupling and Stark effects.
• Absorption coefficient of these MQWs increases with the rise of doping density.
• Electric field dependence of the absorption coefficient is also investigated.
• Well parameters are adjusted to obtain GaNAsBi-based MQWs operating at 1.55 μm.

We present a self-consistent calculation combined with the 16-band anticrossing model in order to investigate the electronic and optical properties of n-doped GaNAsBi/GaAs multiple-QWs operating at 1.55 μm. Optoelectronic features of these quantum structures seem advantageous for the design of photodetector devices. We have found that doping induces a blue shift of the fundamental transition energy for the uncoupled double-QWs with the barrier width Lb = 12 nm. This transition energy shows a red shift when the doped DQWs are coupled (Lb = 2 nm). An applied electric field favors further this shift. The coupling and Stark effects on the spatial distribution of confined electrons density are discussed. The absorption coefficient for the coupled 4 nm GaN.04As.89Bi.07/GaAs DQWs is enhanced compared to the un-doped or uncoupled DQWs. Finally, we have examined the dependence of the absorption magnitude on the doping density and electric field for different values of wells number.

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