Built-in field reduction in InGaN/GaN quantum dot molecules

We use a tight-binding model to study the electronic structure of InGaN/GaN quantum dot molecules grown along the c-axis. This analysis is carried out as a function of the barrier thickness between the two non-identical dots. Our results show that the built-in field is effectively reduced in systems of coupled nitride quantum dots, leading to an increased spatial overlap of electron and hole wave functions compared to an isolated dot. This finding is in agreement with experimental data reported in the literature and is directly related to the behavior of the built-in potential outside an isolated dot.