Atomistic calculation of electronic states in III-V nitride quantum dots

Atomistic calculations of the electronic states in In/sub 0.2/Ga/sub 0.8/N/GaN and GaN/AlN quantum dots (QDs) have been carried out using a polarization-potential-dependent sp/sup 3/ tight-binding method. A valence-force-field method is used for the strain distribution, and a finite-difference method for the polarization-induced potential and field. We find that a strong built-in electric field is induced in the QDs due to the polarization. The field causes the quantum-confined Stark effect in the QDs; i.e., red-shifted transition energies and a spatial separation of electron and hole wave functions.