Localization and homogeneous dephasing relaxation of quasi-two-dimensional excitons in quantum-well heterostructures

The mechanisms of dephasing relaxation (homogeneous linewidth) of quasi-two-dimensional excitons in quantum-well heterostructures are clarified for both localized and delocalized excitons. The recently observed energy and temperature dependences of the homogeneous linewidth h are explained quantitatively. Furthermore, a new exponent for the temperature dependence of h of the localized excitons at low temperatures, the energy dependence of h of the delocalized excitons, and the dependence of h on the quantum-well thickness are predicted.