The exciton-erbium coupling and the excitation dynamics of Er3+ in erbium-doped silicon-rich silicon oxide are investigated using time-resolved measurements of Er3+ luminescence. The dependence of the Er3+ luminescence on the pump power and duration indicates that the exciton-erbium coupling is dominant over carrier-exciton coupling. The results further support the idea that the luminescent Er3+ ions are not in the Si nanoclusters but in the interface region surrounding the nanoclusters. (C) 2001 American Institute of Physics.