Electronic structure of polar and semipolar (11 2 ¯ 2)-oriented nitride dot-in-a-well systems electronic structures of polar and semipolar ... S. Schulz and O. Marquardt

We present a detailed theoretical analysis of the electrostatic built-in fields and the electronic structures of polar and semipolar dot-in-a-well systems. Our theory is based on a symmetry-adapted multiband k·p model, parametrized by the incline angle to the wurtzite c axis, that accounts fully for the three-dimensional quantum-dot structure. As an example, we apply the model to the experimentally relevant semipolar plane (112¯2). We show here that the built-in fields in isolated (112¯2) semipolar quantum dots are strongly reduced compared to an equivalent c-plane structure. Our analysis further reveals that in terms of ground-state transition oscillator strength, the semipolar (112¯2) dot-in-a-well systems show a superior behavior compared with their polar counterpart. We also find that increasing the InN content in the quantum dot up to a critical value leads to the unusual behavior that the ground-state electron and hole wave-function overlap increases and therefore the corresponding oscillator strength. This effect can be attributed to changes in the built-in potential profile inside the semipolar (112¯2) quantum dot.