Heating by exciton and biexciton recombination in GaAs/AlGaAs quantum wells

A comprehensive experimental investigation of exciton and biexciton recombination in GaAs/AlGaAs quantum wells is presented. Exciton and biexciton recombination times are found to be 16 and 55 ps, respectively. A method of determining the dynamics of the exciton temperature is developed. It is shown that both exciton and biexciton recombination processes increase the exciton temperature by an amount as high as $\sim 10$ K. These processes impose a new restriction on the possibility of exciton Bose-Einstein condensation and make impossible its achievement in a system of direct excitons in GaAs quantum wells even for resonantly excited exciton gas.