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 si ngularity is exactly taken into account without any further assumptions bec ause analytical expressions are calculated for the Coulomb matrix elements even for the general three-dimensional case. Due to open boundary condition s, this is an accurate and fast model for calculating the optical propertie s of arbitrary semiconductor structures. The advantage will be demonstrated by an investigation of bulk, quantum-well, and multiquantum-well absorptio n.