The effects of low dose (10(14) ions/cm(2)) oxygen implantation on the subband structure of an AlGaAs/GaAs single quantum well is reported here using photoluminescence and photoreflectance spectroscopy. Postimplantation rapid thermal annealing at 900 degrees C up to 180 s induces compositional interdiffusion resulting in enhanced transition energy shifts and a reduction in the photoluminescence count rate. Comparisons of transition energy shifts show that the electron two to heavy-hole two transition energy is more sensitive than the ground state electron to heavy-hole transition for these annealing conditions.