The composition dependence of room temperature 1.54 mu m Er3+ photoluminescence of erbium-doped silicon:oxygen thin films produced by electron cyclotron resonance plasma enhanced chemical vapor deposition of SiH4, and O-2 with concurrent sputtering of erbium is investigated. The Si:O ratio was varied from 3:1 to 1:2 and the annealing temperature was varied from 500 to 900 degrees C. The most intense Er3+ luminescence is observed from the sample with a Si:O ratio of 1:1.2 after a 900 degrees C anneal and the formation of silicon nanoclusters embedded in the SiO2 matrix. The high active erbium fraction. efficient excitation via carriers, and high luminescence efficiency due to the high quality SiO2 matrix are identified as key factors in producing the intense Er3+ luminescence. (C) 1998 American Institute of Physics.