Calculation of exciton absorption in arbitrary layered semiconductor nanostructures with exact treatment of the Coulomb singularity

An accurate finite-element exciton calculation is presented. The Coulomb singularity is exactly taken into account without any further assumptions because analytical expressions are calculated for the Coulomb matrix elements even for the general three-dimensional case. Due to open boundary conditions, this is an accurate and fast model for calculating the optical properties of arbitrary semiconductor structures. The advantage will be demonstrated by an investigation of bulk, quantum-well, and multiquantum-well absorption.