Optical Properties of Confined and Unconfined Excitons in Semiconductor Quantum Heterostructures.
In this thesis the electronic and optical properties of confined and unconfined excitons in semiconductor quantum heterostructures are investigated. We use multiband effective mass theory to solve the subband structure in which valence band mixing is properly taking into account. With the aid of supercomputer and recently developed k-space sampling technique we can deal with both discrete exciton states and exciton continuum states properly and hence the photoabsorption coefficient. These techniques are applied to calculate the electroabsorption, resonant Raman scattering in GaAs quantum wells, and absorption of above barrier excitons in both type I and type II heterostructures. We find that the valence band mixing is important in explaining the fine structures in the spectrum for the electroabsorption and PLE for above barrier excitons. In the RRS profile, the exciton continuum states are necessary in order to explain the experimental data.
- Pub Date:
- Physics: Condensed Matter