THERMAL STRAIN EFFECTS ON THE EXCITONIC STATES IN GaAs/Al(X)Ga(1-X)As MULTIPLE-QUANTUM WELLS

Temperature-dependent absorption experiments have been performed to investigate the effect of thermal strain in GaAs/AlxGa1-xAs multiple quantum wells clad by thick AlGaAs layers. A temperature-dependent splitting of the heavy-hole and light-hole excitons is observed between 10 and 300 K. This is ascribed to the different thermal expansion coefficient of GaAs and AlxGa1-xAs, causing the constituent GaAs layers to be under weak tensile strain during the optical measurements at different temperatures