Exciton effects in the index of refraction of multiple quantum wells and superlattices

We present theoretical calculations of the index of refraction of multiple quantum wells and superlattices. The model incorporate both the bound and continuum exciton contributions for the Γ region transitions. In addition, the electronic band structure model has both superlattice and bulk alloy properties. Our results indicate that large light-hole masses, i.e., m _lh∼0.23, produced by band mixing effects, are required to account for the experimental data. Furthermore, it is shown that superlattice effects rapidly decrease for energies greater than the confining potential barriers. Overall, the theoretical results are in very good agreement with the experimental data and show the importance of including exciton effects in the index of refraction.