Random approach to determine the broadening of intersubband and interband transitions in (In)GaN/Al(In)N quantum wells

A random approach to determine the broadening of intersubband (IS) and interband (IB) transitions in (In)GaN/Al(In)N quantum wells (QWs) has been proposed in this work. Within this approach, energies and intensities of IS and IB transitions have been calculated for 1000 randomly generated QWs with Gaussian distribution of QW width, barrier width, and indium concentration. From the results of these calculation a histogram of the intensity of optical transitions has been built. In this paper the influence of each parameter (QW width, barrier width, and indium content) on the broadening of IS and IB transitions has been considered independently and then all of the parameters have been taken into account at the same time. The obtained broadenings of IS and IB transitions have been compared with the available experimental data. It has been clearly shown that the large broadening of IS and IB transitions in the (In)GaN/Al(In)N multi-quantum well system results from the statistical distribution of QW sizes and indium concentration.