Intersubband transitions in In_xAl_(1-x)N/In_yGa_(1-y)Nquantum well operating at 1.55 μm

In this paper, we theoretically study the effects of doping concentration N_D and an external electric field on the intersubband transitions in In_xAl_(1-x)N/In_yGa_(1-y)N single quantum well by solving the Schrödinger and Poisson equations self-consistently. Obtained results including transition energies, the band structure, and the optical absorption have been discussed. The lowest three intersubband transitions (E₂-E₁), (E₃-E₁), and (E₃-E₂) are calculated as functions of doping concentration N_D. By increasing the doping concentration N_D, the depletion effect can be reduced, and the ionized electrons will compensate the internal electric field which results from the spontaneous polarization. Our results show that an optimum concentration N_D exists for which the transition 0.8 eV (1.55 μm) is carried out. Finally, the dependence of the optical absorption α ₁₃ (ω) on the external electric field and doping concentration is studied. The maximum of the optical absorption can be red-shifted or blue-shifted through varying the doping concentration and the external electric field. The obtained results can be used for designing optical fiber telecommunications operating at 1.55 μm.