Optical properties of excitons under an axial-potential perturbation

The optical properties and electronic structure of isoelectronic defect bound excitons in semiconductors have been studied. A simple model is used to describe the electron-attractive and hole-attractive isoelectronic defects. This effective-perturbation Hamiltonian model gives a clear physical picture of the two extreme cases of hole-attractive isoelectronic defect bound excitons, i.e., where the total angular momentum of the bound hole is unchanged (J=3/2) and where the orbital angular momentum of the bound hole has been quenched (J=1/2). This model can also be applied to quantum-well (QW) structures. Optical properties of the lowest heavy--light-hole state related excitons in QW's such as transition probabilities, splitting of exciton states in a magnetic field, and exchange splitting are also discussed within this model. By analyzing the experimental data with magnetic fields up to 18 T for 90-\AA{} GaAs/${\mathrm{Al}}_{0.26}$${\mathrm{Ga}}_{0.74}$As QW's, the g values of electrons and holes are estimated to ${\mathit{g}}_{\mathit{e}}$=-0.26\ifmmode\pm\else\textpm\fi{}0.05 for electrons and ${\mathit{g}}_{\mathit{h}}$=0.58\ifmmode\pm\else\textpm\fi{}0.05 for holes.