GaN/AlN constant total effective radius multi-wells quantum rings: Physical properties under well number variation effects

•Well number= a tuning tool to select maximum probability position to find free carriers in system.•Effect of the inner ring radius R0 increase on the ground state energy is larger than number of wells.•To move the resonant energies, effect of the number of wells in systems with larger R0 values is larger.•When R0 increased, the resonant energy moved to higher energies (blue-shift).•Resonant energy had a red-shift by going from single quantum well to double quantum well system.•Further increasing of the numbers of wells led to a blue-shift in the resonant energy.

In this study, effect of the number of wells and quantum ring thickness on subband electronic structure, ground state wave function, Fermi energy and linear refractive index changes of an AlN/GaN constant total effective radius multi-wells quantum ring have been studied. It is shown that, effect of increasing of the inner quantum ring radius R0 on the ground state energy and other physical properties are larger than increasing of the number of wells. This fact helps the simplification of the experiments, since making quantum ring with larger R0 is easier than making multiple-wells quantum rings. However, effect of the increasing of the R0 values in systems with larger number of wells is also larger. Increase of the R0 also leads to increase of the refractive index changes amplitudes. Resonant energy undergo a red-shift by going from single quantum well system to double quantum well system, and further increasing of the numbers of wells leads to a blue-shift. Finally, we propose number of wells as a tuning tool to select the position of the maximum probability of finding free carriers within the system.