Optimal Design of GaN-AlGaN Bragg-Confined Structures for Intersubband Absorption in the Near-Infrared Spectral Range

A method is proposed for the design and optimization of structural parameters of GaN-AlGaN Bragg-confined structures with respect to peak intersubband absorption from the ground to the first excited state, 1 → 2 electronic transition, in the near infrared spectral range. An above-the-barrier bound state was used to extend the range of transition energies above the values available in conventional quantum wells. Intrinsic polarization fields and nonparabolicity effects were taken into account. The selection of optimal parameters, maximizing the absorption at wavelengths of 1.55 and 1.3 μm, was performed by using a simulated annealing algorithm, and optimal structures with infinite superlattices as confinement regions were thus designed. These optimal parameters were then used to set realistic, finite structures with a small number of layers, the performance of which was re-evaluated by solving the Schrödinger-Poisson equation self-consistently for a few different levels and profiles of doping.