- We have investigated the effects of thermal cycling on the optical properties of In0.2Ga0.8As/GaAs single quantum well films bonded to Si(001) via the epitaxial lift-off technique. The optical and structural quality of the bonded films were monitored using cathodoluminescence (CL) imaging and spectroscopy. The films were stable through the temperature range (500–700 °C) used in normal InxGa1−xAs device processing. However, annealing at temperatures greater than ∼700 °C resulted in layer intermixing accompanied by a blue-shift in the CL peak energy. The shifts in the CL peak energy were modeled by considering In–Ga interdiffusion at the interface and solving the Schrodinger equation using appropriate band profiles for this region.