Effects of internal piezoelectric field on electronic states of InGaN quantum dots grown on GaN

Abstract

We have calculated the electronic structure of an In 0.2Ga 0.8N pyramidal quantum dot (QD) in a GaN barrier layer using a polarization-potential-dependent sp 3 tight-binding method. A valence-force-field method was used for the strain calculation. For the QD with a bottom diameter of 86.4 Å, height of 20.8 Å, and facet inclination angle ( φ) of 30°, the maximum piezoelectric field is 1.64 MV/cm. The energy gap shows a red shift of 0.10 eV due to the quantum-confined Stark effect. The field causes a spatial separation of the electron and hole wave functions in the QD. The results are compared with those for the prismatic QD ( φ=90°).