The effect of confinement on the temperature dependence of the excitonic transition energy in GaAs/AlxGa1−xAs quantum wells

We determined by means of photoluminescence measurements the dependence on temperature of the transition energy of excitons in GaAs/AlxGa1−xAs quantum wells with different alloy concentrations (with different barrier heights). Using a fitting procedure, we determined the parameters which describe the behavior of the excitonic transition energy as a function of temperature according to three different theoretical models. We verified that the temperature dependence of the excitonic transition energy does not only depend on the GaAs material but also depends on the barrier material, i.e. on the alloy composition. The effect of confinement on the temperature dependence of the excitonic transition is discussed.