We have calculated the electronic structure of an In0.2Ga0.8N 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 Angstrom, height of 20.8 Angstrom, and facet inclination angle (phi) of 30degrees, 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 (phi = 90degrees). (C) 2002 Elsevier Science B.V. All rights reserved.