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-angstrom GaAs/Al0.26Ga0.74As QW's, the g values of electrons and holes are estimated to g(e) = -0.26 +/- 0.05 for electrons and g(h) = 0.58 +/- 0.05 for holes.