The effects of doping layer location on the electronic and optical properties of GaN step quantum well

•The intersubband transitions and optical absorptions are numerically studied.•The optical absorption display different dependent behavior on the doping layer concentration.•The doping in the middle of quantum well is advantageous to obtain higher transitions.

In the present work, the intersubband transition and the optical absorption coefficient between the ground and the first excited states in the Si-δ-doped step AlGaN/GaN quantum well were theoretically studied by solving Schrödinger-Poisson equations self-consistently within the framework of effective mass approximation. The delta-doped layer was inserted in three different locations (middle of the quantum well, middle of the step quantum well and middle of the left barrier). The obtained results show that the energy difference between the ground and the first excited state and the optical absorption depend not only on the doping layer concentration but also on its location. The shape of the confining potential and the wavefunctions were also changed depending on the doped layer location. It was found that doping in the middle quantum well is advantageous to obtain an optical absorption with a higher energy separation; however, doping in the left barrier gives us an optical absorption with a lower energy separation. The obtained results in optical absorption give us a new degree of freedom in optoelectronic devices based on intersubband transitions.